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Full text of "Golden Book of Chemistry Experiments"

612:195 



THE GOLDE 






M CHEMISTRY 
EXPERIMENTS 



HOW TO SET UP A HOME LABORATORY-OVER 200 SIMPLE EXPERIMENTS 





THE GOLDEN BOOK OF 



How to Set Up a Home Laboratory 
Over 200 Simple Experiments 

BY ROBERT BRENT 
ILLUSTRATED BY HARRY LAZARUS 




GOLDEN PRESS 




NEW YORK 



Copirishl l'y60 b] Golden Preii. Inc. All rirhU reserved. Printed in L.S.A. Pulli;hed In Golden Pre,!, Inc.- Rockefeller Cenler. Ke* York 20. >'. Y. 



Words L seel by Oiieniist 



s 



Acid: a hydrogen-containing compound 
that releases hydrogen ions in solution. 

Alloy: a material made up by combining 
two or more metals. 

Analysis: breaking down a compound 
into two or more substances. 

Anhydrous: free from water. 

Atom: the smallest unit of an element 
that can enter into the making of a 
chemical compound. 

Atomic weight: the weight of an atom 
compared with the weight of an oxygen 
atom set at 16. 

Base: a compound containing the hy- 
droxide group (OH). 

Catalyst: a substance that helps in a 
chemical reaction without itself being 
changed. 

Chemical change: a change of a sub- 
stance into another substance having 
different properties. 

Chemistry: a branch of science dealing 
with the compositions of substances and 
the changes that can be made in them. 

Combustion: burning; a chemical 
change that produces heat and light. 

Compound: a substance consisting of 
two or more different kinds of atoms in 
definite proportions by weight. 

Crystal: a solid in which atoms or mole- 
cules are arranged in a definite pattern. 

Density: the weight of a liquid or a 
solid in grams per cm 3 or milliliter. 

Distillate: a liquid that has been turned 
into vapor and again cooled into a liquid. 

Distillation: the process of producing 
a distillate. 

Ductile: capable of being drawn out into 
a wire. 

Electrolysis: breaking down a substance 
by passing an electric current through il. 

Electrolyte: a substance that, when in 
a solution or when melted, will conduct 
an electric current. 



Element: a substance that contains only 
one kind of atoms. 

Equation: a complete description of a 
chemical reaction by the use of symbols, 
formulas, and signs. 

Evaporation: the changing of a sub- 
stance into vapor: also the process of re- 
moving water by heating. 

Filtrate: a liquid obtained by nitration. 

Filtration: the process of straining a 
liquid from a solid through porous mate- 
rial, usually filter paper. 

Formula: a group of symbols and num- 
bers giving the composition of a com- 
pound. 

Hydrate: a compound containing loosely 
bound water of hydration (water of 
crystallization) that can be driven off 
by healing. 

Hydroxide: a compound that contains 
the hydroxyl (OH) radical. 

Iou: an electrically charged atom or 
group of atoms (radical). 

.Malleable: capable of being hammered 
or rolled into a thin sheet. 

Matter: anything that lakes up space 
and has weight. 

Metal: an element that is a good con- 
ductor of electricity, has luster, and 
whose oxide forms a base with water. 

Metalloid: an element that has proper- 
lies of both metals and nonmetals. 

Mixture: a mingling of substances not 
combined chemically. 

Molecular weight: the sum of the 
atomic weights of the atoms thai make 
up a molecule of a compound. 

Molecule: the smallest unit of a com- 
pound that can exist in the free state. 

Neutralization: the reaction of an acid 
and a base to give a salt and water. 

Nonmetal: an element that is a poor 
conductor of electricity", does not have 
luster, and whose oxide forms an acid 
when combined with water. 



Organic chemistry: the chemistry of 
the carbon compounds. 

Oxidation: the process by which a sub- 
stance combines with oxygen. 

Precipitate: an insoluble solid formed 
in a solution by chemical reaction. 

Radical: a group of atoms that behave 
chemically as a single atom. 

Reaction: a chemical change. 

Reduction: removal of oxygen; the op- 
posite of oxidation. 

Salt: compound (other than water) 
formed by the reaction of an acid and 
a base. 

Saturated solution: a solution that 
contains the maximum amount of solute 
under the conditions. 

Solubility: the number of grams of a 
solute needed lo make a saturated so- 
lution in 100 grams of solvent. 

Solute: the substance dissolved in a 
solvent. 

Solution: a non-settling mixture of a 
solute in a solvent. 

Solvent: a liquid in which a solute is 
dissolved. 

Sublimation: a process by which a sol- 
id is lunied into vapor and again cooled 
into a solid without passing through a 
liquid stage. 

Subscript: a small numeral indicating 
the number of atoms of a certain element 
in the formula of a compound. 

Substance: any specific kind of matter 
whether element, compound, or mixture. 

Symbol: a letter or two letters repre- 
senting one atom of an element. 

Synthesis: the making up of a com- 
pound from simpler compounds or from 
elements; the opposite of analysis. 

Valence: I he number of hydrogen atoms 
which one atom of an element can dis- 
place or with which it can unite. 




©intents 








WHAT CHEMISTRY IS 

Words Used by Chemists 2 

Tiie Importance of Chemistry \ 

Chemists of the Past 6 

YOUR HOME LABORATORY 

Equipment for Chemistry 9 

Setting up Your Home Laboratory 10 

Making Apparatus for Experiments 12 

Scientific Measurements 14 

Correct Laboratory Techniques 16 

TIIE SCIENTIFIC APPROACH 

Mr. Faraday's Candle 18 

You — Scientist! 20 

Elements. Compounds, and Mixtures 22 

WATER AND GASES 

Water — Our Most Important Compound. . . 2-1 

Oxygen — The Breath of Ldte 26 

Hydrogen — Lightest of All 28 

Carbon Dioxtde 30 

Nitrogen and Its Compounds 32 

Chlorine — Friend and Foe 34 

CHEMICAL FORMULAS 

Chemical Shorthand 36 

The Periodic Table of the Elements 38 

ACIDS, BASES, AND SALTS 

The Mystertes of Solutions 40 

Working with Acids 42 

Working with Bases 43 

Salts — Chemicals of Many Uses 46 

NONMETALS 

Iodine — Violet or Brown? 48 

Sulfur and Its Compounds 50 

Silicon — The Element You Step on 54 

Boron — Future Rocket-Power Element?. . 56 



METALS 

Sodium and Potassium 58 

Calcium — for Building 60 

Let's Compare Two Metals 62 

Alumlnum — in Abundance 64 

Manganese — Metal of Many Colors 66 

We Live in an Age of Iron 68 

Copper — Yesterday, Today 70 

Silver — One of the "Noble" Metals 72 

MORE ABOUT FORMULAS 
Valences and Formulas 74 

ORGANIC CHEMISTRY 
Carbon — Element of a Million Compounds. 76 

The Chemistry of Carbon Compounds 78 

The Formulas of Carbon Compounds 80 

A Lot of Hydrocarbons 82 

Carbohydrates — Sweet and Bland 84 

Many- Kinds of Alcohols 88 

Carboxylic Acids 90 

Fats and Oils for Energy* 92 

Soap and Soap Making 94 

Proteins — The Body-Buildlng Foods 96 

Colloidal Dispersions 100 

Natural and Artifkhal Fibers 102 

Plastics — A Modern Giant 104 

CHEMICAL MATHEMATICS 
Working out Chemical Equations 106 

THE FUTURE OF CHEMISTRY 
What's Ahead in Chemistry? 109 

Where to Get Chemicals and Equdpment. . .110 

Common Chemicals and Their Formulas Ill 

Index 112 




EVERY HOME KITCHEN IS A CHEMICAL LABORATORY. .-- 
COOKING AND CLEANING ARE CHEMICAL PROCESSES. 



I lie importance oi Onemistry 



There is hardly a boy or a girl alive who is not 
keenly interested in finding out about things. And 
that's exactly what chemistry is: FINDING OLT 
ABOUT THINGS — finding out what things are 
made of and what changes they undergo. 

What things? Any thing! Every thing! 

Take a look around you. All the things you see — 
and lots of things you can't see — have to do with 
the science of chemistry. 

Let's start with yourself. The air you breathe is 
a mixture of chemical substances and the process of 
breathing is a chemical reaction. The foods you eat 



are all chemical products and the ways in which 
your body turns them into muscles and bones and 
nerves and brain cells are some of the greatest of all 
chemical mysteries. 

The clothes you wear, the books you read, the 
medicine you take, the house in which you live — 
all these are products of chemistry. So is the family 
car — the metal in it, the rubber on which it rolls, 
the gas that moves it. 

Nature itself is a tremendous chemical laboratory. 
Everything in nature is forever passing through 
chemical changes. Here on earth, plants and animals 




CHEMISTRY PROVIDES FUEL FOR 
ALL KINDS OF TRANSPORTATION. 



PURIFICATION OF WATER 



grow, die, and decay: rocks crack and crumble under 
the influence of air and water. In the universe, new 
stars are formed, others fade. The sun that gives us 
heat and light and energy is a flaming furnace of 
chemical processes that will eventually burn itself 
out, billions of years from now. 

Chemistry is one of the most important of all sci- 
ences for human welfare. 

Chemistry means the difference between poverty 
and starvation and the abundant life. The proper 
use of chemistry makes it possible for farmers to feed 
the world's ever-increasing population, for engineers 
to develop new means of transportation and com- 
munication that will bring the peoples of the world 
closer together, for doctors to cure the diseases of 
mankind, for manufacturers to produce the thou- 
sands of items that are necessary for better and 
richer living. 

And this is only the beginning. 

Within recent years, scientists have succeeded in 
penetrating into the innermost secrets of chemical 
substances and have begun to make use of the tre- 
mendous force that lies hidden in them. This atomic 
power opens up amazing possibilities for the future. . 

You will live in a world in which chemistry will 
become ever more important. To understand that 
world it is necessary to understand the truths and 
laws on which modern chemistry is based and to learn 
how chemists of the past unraveled them. 

This book will help you get this insight — not 
alone by your reading it, but also by your conscien- ... 
tiously doing the experiments described and learning ^ 
what each of them has to tell vou. 




OIL IS THE BASIS FOR COUNTLESS CHEMICAL PRODUCTS. 




ATOMIC ENERGY FOR 
THE FUTURE 



m 



■. 



ilfeyt 



PAPER AND PRINTERS' 
INK ARE MADE WITH 
HELP OF CHEMISTRY. 









copper 



SYMBOLS USED BY ALCHEMISTS 



Okeimsts of ike JPasf 

M.ua' thousa^t) years ago, an early ancestor of 
yours pushed a stick into the hot lava flowing from 
an erupting volcano. The stick burst into Fire. He 
held it up as a torch. It gave off light and heat and 
finally turned into ashes. 

This ancient man might be considered the world's 
first chemist. He had actually taken a substance 
called wood and had, by a chemical process called 
combustion or burning, turned it into something else. 

The discovery of the use of fire was the first great 
step leading toward modern chemistry. Fire made it 
possible to turn raw foodstuffs into edible meals, to 
bake shaped clay into pottery, to make glass, to 
drive metals out of their ores. 

For thousands of years people were chiefly inter- 
ested in the results of what they did — they didn't 



care about what happened or why it happened. It 
was only about 2,500 years ago that philosophers 
began to wonder about what things were made of 
and what happened when a thing changed into some- 
thing else. 

Around 400 B. C, in Greece, a thinker by the name 
of Empedocles came up with an idea that seemed to 
make sense. He explained that everything in the 
world was made from just four things which he 
called "elements ": fire, water, air. and earth. Think 
of that burning stick mentioned above. It gave off 
fue — so, obviously, the stick had to contain fire. 
It sizzled — which meant there was water in it. It 
smoked — and smoke would be some kind of air. It 
left ashes — and ashes are earth, as certainly every- 
one should know. 

Everyone — except another Greek, Demorritus, 
born around the time when Empedocles died. He 
had a different notion — that all matter was made 
up of tiny particles which he called atomos — some- 
thing that cannot be cut further. 

But Democritus didn't get very far with his idea. 
The greatest Greek philosopher of the day, Aristotle, 
held out for the four elements. And because of his 
great reputation this false idea governed the thinking 
of scientists for two thousand years — because no 
one dared suggest that he knew better than the great 
Aristotle! 




BRONZE-AGE MAN WAS ONE 
OF THE EARLIEST CHEMISTS. 



DEMOCRITUS INSISTED THAT 
MATTER CONSISTS OF ATOMS. 



PARACELSUS TOLD HIS PU- 
PILS TO USE EXPERIMENTS. 



BOYLE INVESTIGATED GASES 
AND BROKE OLD TRADITIONS. 



In the meantime, scientists of Arabia began work 
in a subject they called alchemy — from Arabic at, 
the, and kimia, pouring together. They mixed things 
and boiled and distilled and extracted in the hope, 
some day, of finding a way of making GOLD! They 
discovered a great number of things not previously 
known, developed many sound laboratory methods, 
and gave the science of chemistry its name — but 
they never created the slightest speck of gold. Nei- 
ther did a great number of European alchemists. 

For hundreds of years chemistry made little head- 
way. Then, in 1525, a Swiss doctor and scientist 
spoke up. He had the imposing name of Theophras- 
tus Bombastus Paracelsus von Hohenheim. He chal- 
lenged his students to tear up their books with the 
old theories that had been developed through reason- 
ing only and to find out for themselves through ex- 
periments whether a scientific theory was right or 
wrong. But only a few people paid attention to him. 
More than a hundred years passed before an Eng- 
lishman, Bobert Boyle, in 1661, succeeded in killing 
off the old idea of the four elements. He did it by 
establishing that there are many elements — sub- 
stances that cannot be formed by other substances 
and cannot be broken into other substances. 

Another hundred years went by. Then, at the time 
of the American Revolution, the day finally dawned 
for modern chemistry. 



A Swede, Karl Scheele, and an Englishman, Joseph 
Priestley, discovered oxygen, and a Frenchman, An- 
toine Lament Lavoisier, explained the true nature 
of burning and made up the first scientific listing of 
all known elements — twenty-eight at the time. 

Within a few years, more elements were found. 
With the help of electricity, an English chemist, 
Humphry Davy, in a single year brought to light 
six new metals — among them sodium, potassium, 
calcium, and magnesium. 

Twenty years later, in 1828, another important 
break-through occurred. A German chemist, Fried- 
rich Wohler, working in his laboratory produced a 
chemical, urea, that had never before been made 
outside the body of a living animal. 

More and more things were happening. New ele- 
ments were discovered, new chemicals created. The 
advances in chemistry greatly influenced industry, 
agriculture and medicine. 

And then, in 1898, the Polish-born Marie Curie 
and her French husband, Pierre, discovered the "mir- 
acle element/' radium. This opened up a whole new 
age in chemistry. 

Within the last fifty years, chemistry has moved 
forward with giant steps. But not a single one of 
these steps would have been possible without the 
dedicated work of the chemists of the past who laid 
the foundation on which modern chemistry rests. 




PRIESTLEY USED HEAT OF 
SUN TO PRODUCE OXYGEN. 



LAVOISIER GAVE THE RIGHT 
EXPLANATION OF BURNING. 



DAVY BROUGHT ELECTRICITY 
INTO CHEMICAL RESEARCH. 



MARIE CURIE AND HER HUS- ■ 
BAND DISCOVERED RADIUM. 



tpiipmenf iof OJieiiiisfrj 



Some of the greatest discoveries in chemistry were 
made by scientists who had no special equipment 
but simply used whatever was at hand. 

In your home lab experiments it will pay you 
to follow the example of these early chemists. Put 
your imagination to work. Lse whatever suitable 
equipment you can find around the house (as sug- 
gested in column to the right) and buy only what is 
absolutely necessary (as shown below). Some items 
may be purchased in a local drugstore or scientific 
supply shop. If not, you can buy them from one of 
the suppliers listed on page 110. 

Later on — if you really get excited about chem- 
istry — you may want to use your pocket money for 
some of the lab equipment shown on page 8. 

LABORATORY WARE FOR HOME LAB 



IMPROVISED EQUIPMENT FOR HOME LAB 

screwtop can 
1 pint 




test tube jg-~ 
brush "c : 




IN A REGULAR LAB, 
EVERYTHING HAS ITS 
PLACE AND IS NEAR 
AT HAND. AIM TO 
KEEP YOUR OWN LAB 
AS WELL ORGANIZED. 



Jetting Up Your JHLoine l^ahorator 



w 



BOX TO HOLD HOME 
LAB CAN BE MADE 
FROM PLYWOOD. KEEP 
BOX LOCKED WHEN 
NOT IN USE AS A PRO- 
TECTION FOR YOUNG- 
ER CHILDREN. 




siphon 
bottle 



It is possible that you may be permitted to work 
at the kitchen table when this is not in use. But it 
is far better if you have a place where you will not 
be disturbed and where you can store your equip- 
ment — a corner in your room, or in the basement 
or the garage. 

These are the things you'll need in your lab: 

Work Table. An old. sturdy table will do. Cover 
it with a plastic top to protect the wood. 

Water Supply. If you have a faucet nearby, 
fine. Otherwise, make a siphon bottle (page 11). 

Waste Disposal. If you can dump your waste 
directly into the kitchen drain (NOT into the sink), 
you are all right. If not, collect it in a plastic pail 
to be thrown out when you're finished. 

Source of Heal. In the regular laboratory, spe- 
cial gas burners are used. In the home lab, you can 
use a burner for denatured alcohol. Have a shallow 
metal pan under the burner for fire safety. 

Storage. If there's no one around to disturb your 
chemicals and equipment, an open shelf is OK. 
Otherwise, use a box that can be locked up. 

Containers. Keep chemicals in glass jars and 
bottles. LABEL THEM ALL CLEABLY. 

Stands. Make your own test tube stand as well 
as stands for holding glassware for heating. 



IF YOU DO NOT 
HAVE RUNNING 
WATER IN YOUR 
LAB, MAKE SIPHON 
FROM A 1 -GALLON 
BOTTLE. START 
SIPHON BY BLOW- 
ING THROUGH 
L-SHAPED GLASS 
TUBE. SPRING 
CLOTHES PIN 
REGULATES 
WATER FLOW. 





YOU CAN MAKE A SIMPLE TEST TUBE 
STAND FROM A SALT BOX. CUT OUT 
SIDE AND USE CUT-OUT SECTION TO 
KEEP TEST TUBES LINED UP STRAIGHT. 



REGULAR LAB STAND FOR 
TEST TUBES CAN BE PRO- 
DUCED FROM STRIPS OF 
Vi-INCH WOOD. FOLLOW 
PATTERNS BELOW TO MAKE 
TWO SIDES AND THREE 
HORIZONTAL PIECES. DRILL 
HOLES. ASSEMBLE WITH 
THIN TACKS. 



cut lipstick 
container at 
dotted line 



use half 
of Thermos 
bottle cork 





\<— 3""» 



make 2 of these — cut 
one along dotted line 



lip- 
stick tube 
through cork 



{& 


& o o o o o 


& 


*®*o O O O O 



♦I 

2% 



I <— 3 Vi " — > | 



MAKE AN ALCOHOL BURNER FROM INK 
BOTTLE, THERMOS BOTTLE CORK, AND LIP- 
STICK CONTAINER. BUY WICK AT A HARD- 
WARE STORE. 




USE A PAIR OF PLIERS FOR MAKING 
THESE STANDS FROM CLOTHES HANGER 
WIRE. ALSO MAKE THE FUNNEL STAND 
ILLUSTRATED ON PAGE 9. 



STRIP OF THIN CARDBOARD MAKES 
AN ADEQUATE TEST TUBE HOLDER. IF 
YOU LIKE, YOU CAN MAKE A HOLDER 
FROM CLOTHES HANGER WIRE AS 
SHOWN HERE. 




11 



7 cm 



l« — 5 cm >l 




T 



I 



No. 5 



FIRST DECIDE ON 
APPARATUS YOU 
WILl NEED. THEN 
FIGURE OUT SIZES 
OF PARTS. THESE 
ARE THE PARTS 
FOR THE SAFETY 
GAS GENERATOR 
ON PAGE 29. 




iViakiiig Apparatus ior Jc/xperiinriieiiiiis 



Most of your chemical experiments you will perform 
in test tubes and jars. But occasionally you will need 
an apparatus — a device consisting of bottles and 
stoppers, glass and rubber tubing. 

A good chemist takes pride in bis apparatus. He 
makes it with great care — not just for looks but. 
more important, for safety. An apparatus that leaks 
flammable gas can be very dangerous. 

Before you start to put an apparatus together, 
make a simple drawing of it so that you will know 
what it will consist of. Then get out the various parts 
you will need to put it together. 

To make an apparatus, you need to know how to 



cut a glass tube, how to bend it. and how to draw 
it to a jet point. See page 13. 

It is wise to use glass tubes of one diameter only, 
with rubber tubing to fit. Glass tubes of an on/side 
diameter of 6 millimeters tit snugly into the holes in 
the usual rubber stoppers. Rubber tubing of an in- 
side diameter of Jjjj* fits over the 6mm glass tubes. 

To determine the right size stoppers to use in the 
bottles of your apparatus, measure the mouths of 
the bottles against the stoppers shown below in 
actual size. Order stoppers by number. Keep a selec- 
tion of different sizes on hand. 

Follow tlif safety precautions on page 16. 



1 5 mm 



10 mm 



1 7 mm 



1 3 mm 



19 mr 



20 mm 



24 mm 



16 mm 



26 mm 



20 mm 



27 mm 




23 mm 



THESE ARE THE ACTUAt SIZES OF RUBBER STOPPERS. BY KNOW WHICH TO ORDER. No. FITS THE 16 mm TEST 

MEASURING THEM AGAINST YOUR tAB WARE YOU WltL TUBE. No. 5 FITS 4-OZ. WIDE-MOUTH. BOTTtE. 



12 



CUTTING GLASS TUBES 




FIRE GLAZING 
CUT EDGES 





ROUND THE ROUGH EDGES OF CUT 
TUBE BY ROTATING IN FLAME. THIS 
IS CALLED "FIRE GLAZING." 




\3^ 
heat for about 1 Vi inches 



away from you 

1 MAKE SINGLE SCRATCH WITH FILE— DO NOT "SAW." 

2 HOLD TUBE WITH BOTH HANDS.THUMBS BELOW MARK. 

3 SNAP TUBE INTO TWO PIECES WITH A QUICK JERK. 

BENDING GLASS TUBES 




1 ! HEAT SECTION OF TUBE EVENLY WHERE YOU WANT 
TO FORM JET POINT, BY ROLLING IT IN THE FLAME. 

2 WHEN SOFT, PULL SLOWLY. CUT APART WHEN HARD. 




II jHEAT THAT PART 
OF TUBE EVENLY 
WHERE YOU WANT TO 
BEND IT, FOR ABOUT 
TWO INCHES, BY ROLL- 
ING AND MOVING 
THE TUBE BACK 
AND FORTH. 

«WHEN GLASS IS 
FT, REMOVE FROM 
FLAME. BEND QUICK- J 
LY. HOLD UNTIL THE 
GLASS HARDENS. 




IF HEATED TOO 
MUCH, THE TUBE 
WILL FLATTEN 
OR "BUCKLE." 



13 



qOO meters 




>cientixic -ML 



enfs 



easTLireiii 1 

I>" science, the metric system is preferred over our usual sys- 
tem. It is much easier to work with when once you have learned 
it — for instead of dividing or multiplying by 12 or 32 or 16 
to go from one unit to the next, you simply move the decimal 
point. Just remember these two things: 

1. That the names of the basic units are meter for lengths, 
liter for volumes, grams for weights — abbreviated to m, 1, 
and g (without a period after them). 

2. That 1000 of a kind are called kilo; 100, hekto: 10, deca; 
1/10 is called deci; 1 100, centi; 1 1000, milli. 



METRIC UNITS OF LENGTH 

1000 meters (m) = 1 kilometer (km) 
1 meter (m) = 1 000 millimeters (mm) 
1 meter (m) = 39.37 inches 
2.540 centimeters (cm) = 1 inch 



1 cubic centimeter = 

1 cm 1 = 1 cc = 

1 milliliter = 

1 ml - 



Making a Model 

of a Cubic 

Centimeter 




BOTTOM tINE OF FIGURE 
TO THE RIGHT IS 1 DECI- 
METER (1 dm) OR 10 CEN- 
TIMETERS (10 cm) OR 100 
MIUIMETERS (100 mm). 

FRONT SURFACE OF FIGURE 
IS 1 SQUARE DECIMETER (1 
dm 1 ) OR 100 SQUARE CEN- 
TIMETERS (100 cm'). 

VOLUME OF WHOLE FIGURE 
IS 1 CUBIC DECIMETER (1 
dm") OR 1000 CUBIC CEN- 
TIMETERS (1000 cm' OR 
1000 cc) OR 1000 MILLI- 
LITERS (1000 ml) OR 1 LITER 
(1 I). 1 I WATER WEIGHS 
1 KILOGRAM (1 kg). 



METRIC UNITS OF VOLUME METRIC UNITS OF WEIGHT 

1 liter (I) =: 1000 cubic centimeters 1000 grams (g) = 1 kilogram (kg) 

(cm 1 or cc) 1 gram (g) = 1000 milligrams (mg) 

1 liter (I) = 1000 milliliters (ml) 1 gram (g) — 0.035 ounces avoirdu- 

1 liter (I) = 1.06 quarts (liquid) Pois 

0.946 liter (I) = 1 quart (liquid) 28.350 grams (g) = 1 ounce avoir- 
dupois 



'.<'.''.'■.<'.'■.''.<'/,<' 



' ' ' // S =^ 



.y / y y y 



z: 



~z_ 



/ 



/ 



/ 



/ 



/ 

A 



' 



/ 



/ 



l 



/ 



f 

/ 



1 cubic decimeter = 1 liter = 1000 cubic centimeters = 1000 milliliters 



;:|lllm|llil,:ul 
1 



TTnTTTTTFTTTTTTTTpTTTTTITT 
3 4 



trrnrrn 



mUI,i||iiilifiil|liiiliili IIiiiiIiiI 

7 8 9 10 



T-rr 



I I I I I 



I 1 1 1 ' 



centimeter 
ruler 

inch 
ruler 



MAKING A HAND BALANCE 




MAKE THE TWO PANS FOR 
THE HAND BALANCE FROM 
TOP AND BOTTOM OF A 
FROZEN-JUICE CAN. OPEN 
CAN AT SIDE. CUT THE 
PANS WITH TIN SNIPS. 



FOR MANY EX- 
PERIMENTS YOU 
NEED TO WEIGH 
CHEMICALS. FOR 
THIS, MAKE A 
HAND BALANCE. 




USE PATTERN BELOW 
TO MAKE BEAM WITH 
TONGUE ATTACHED. 
CUT CAREFULLY WITH 
TIN SNIPS. FOLD BEAM 
LENGTHWISE. PUNCH 
HOLES WITH NAIL. 




rider 




-2.5g 



IVA 



^ICKEQ = 5g 



YOU CAN USE COINS TO 
WEIGH 2.5 g, 5 g, 7.5 g, 10 g, 
ETC. FOR SMALLER WEIGHTS, 
CUT A TIN STRIP TO WEIGH THE 
SAME AS A NICKEL. THEN CUT 
IT IN FOUR 1 g AND TWO .5 g 
WEIGHTS. 



I 



=o=l 



ASSEMBLE BALANCE 
AS SHOWN. IF 
BEAM DOES NOT 
BALANCE HORI- 
ZONTALLY, PUT 
SMALL "RIDER" CUT 
FROM TIN CAN 
OVER ONE ARM OF 
THE BEAM. 




l g 


i g 


i g 


i g 


& 



MAKING A GRADUATE 

A GRADUATE IS USED FOR 
MEASURING LIQUIDS. 

YOUR 6" TEST TUBE HOLDS 
22 ml. YOU CAN USE IT FOR 
ROUGH MEASUREMENTS: 
TUBE NOT QUITE FULL IS 20 
ml, NOT QUITE HALF FULL 10 
ml. FOR SMALLER AMOUNTS, 
COPY THE RULER TO THE 
RIGHT AND ATTACH IT TO 
THE SIDE OF A TEST TUBE 
WITH SCOTCH TAPE FOR 
MEASURING mi's. 



Scotch 
tape 



read at bottom 
of hollow 
(called miniscus) 







pattern for bar and O tongue for hand balance 



o 



o 



o 



o 



M 



o 



pattern for support for hand balance 



tack 




COPY THE PATTERNS ABOVE 
ONTO A PIECE OF PAPER. 
TRANSFER DESIGNS TO PIECE 
OF TIN CAN. CUT OUT AND 
BEND AS SHOWN TO THE LEFT. 



15 




(§) SET OUT ALL THE 

EQUIPMENT AND THE 
CHEMICALS YOU NEED. 



3 FOLLOW 

INSTRUCTIONS 

IN PERFORMING 

THE EXPERIMENT. 



f PLACE USED EQUIPMENT TO THE 
E FOR CLEANING WHEN EXPERI- 
MENT IS COMPLETED. 





4 MAKE 
NOTES OF 
YOUR 
FINDINGS. 



Oorrect Laboratory 1 ecliiiiques 



In your home laboratory, three considerations are 
of the greatest importance: SAFETY, NEATNESS, 
and EXACTNESS. 

SAFETY — All the experiments in this book are 
safe when done in the correct laboratory way as 
shown on these pages. 

Treat chemicals with respect. Never taste any- 
thing unless specifically told to do so. If there are 
younger children in the family, lock up your - chem- 
icals when you are not working with them. 

Protect your clothes with a plastic apron. 

Be careful with fire. W hen you use your alcohol 
burner, have a metal pan under it for safety. 




NEATNESS— Get the habit of lining up equip- 
ment and chemicals you need on one side and placing 
used items on the opposite side — keeping the space 
between them clear for your experiments. 

Put chemicals away and clean glassware as soon 
as you have finished an experiment. 

EXACTNESS — Label all bottles and jars con- 
taining chemicals clearly and correctly. 

Y\ here amounts of chemicals are not given, use 
the smallest amount that will tell you what you want 
to know. 

Observe the chemical reactions carefully and make 
complete notes of them as you go along. 







PLAY SAFE WHEN YOU PUT A GLASS TUBE IN A STOPPER. 
PROTECT YOUR HANDS BY WRAPPING TOWEL AROUND 
THEM. MOISTEN GLASS TUBE AND STOPPER WITH WATER, 
THEN PUSH THE TUBE INTO THE STOPPER WITH A SCREW- 
DRIVER MOTION. 



WHEN YOU MAKE AN APPARATUS FOR A CHEMICAL EX- 
PERIMENT, MAKE SURE THAT ALL CONNECTIONS ARE AIR- 
TIGHT. USE THE RIGHT SIZE STOPPER FOR MOUTH OF 
CONTAINER, GLASS TUBES THAT FIT SNUGLY INTO THE 
STOPPER HOLES, AND TIGHT-FITTING RUBBER TUBING. 



16 



TRAINED CHEMISTS NEVER PUT 
STOPPER OF BOTTLE ON DESK — 
THEY KEEP IT IN ONE HAND. 

1, TAKE STOPPER OFF BOTTLE 
WITH YOUR LEFT HAND. 

2 KEEP STOPPER IN THE LEFT 
HAND WHILE YOU POUR FROM 
THE BOTTLE IN YOUR RIGHT, 
WITH THE LABEL FACING UP. 
THEN REPLACE THE STOPPER. 




USE A GLASS ROD TO 
DIRECT THE STREAM 
WHEN POURING A LIQ- 
UID FROM ONE CON- 
TAINER TO ANOTHER. 



WHEN HEATING A LIQUID IN A TEST 
TUBE, HOLD TUBE WITH A HOLDER. 
KEEP THE TUBE MOVING. DO NOT 
HEAT BOTTOM OF TUBE — CON- 
TENTS MAY "BUMP" AND SQUIRT 
OUT. NEVER POINT MOUTH OF TEST 
TUBE TOWARD YOURSELF OR TO- 
WARD ANYONE ELSE. 



WHEN HEATING A SOLID IN A TEST TUBE, 
PLACE THE TUBE IN A STAND AND MOVE 
THE FLAME OF YOUR BURNER BACK AND 
FORTH TO HEAT THE CONTENTS EVENLY. 




USE A TEST TUBE BRUSH FOR CLEANING TEST 
TUBES. RINSE IN COLD WATER. 



DO NOT BRING TEST 
TUBE UP TO YOUR 
NOSE FOR SMELLING. 
INSTEAD, WAFT THE 
ODORS TOWARD YOU 
WITH YOUR HAND. 



17 









PLACE A BURNING CANDLE IN THE SUN AND CATCH 
THE SHADOW ON A PIECE OF WHITE PAPER. YOU 
WILL DISCOVER THAT IT IS THE BRIGHTEST PART 
OF THE FLAME THAT CASTS THE DARKEST SHADOW. 



CANDLE FLAME IS BURNING VAPOR 




iVir, Faraday's Oandle 

In the winter of 1859, Michael Faraday, a great 
British scientist, gave a number of lectures for young 
people. The talks dealt with one subject only: the 
features or "phenomena" of — a candle! 

"There is not a law." Faraday told his listeners, 
"under which any part of this universe is governed 
which does not come into play and is touched upon 
in these phenomena. There is no better, there is no 
more open door by which you can enter into the 
study of natural philosophy than by considering the 
phenomena of a candle." He then set out to prove 
his point by lighting a candle and demonstrating all 
the processes involved. 

In burning a candle you start with a SOLID sub- 
stance that turns, first, into a LIQUID, then into a 
GAS (or, more correctly, into a gas-like vapor). The 
melted candle grease is held in a level position by 
GRAVITY yet seems to defy gravity by rising in the 
wick by a force called CAPILLARY ACTION. In 
burning, the candle produces ENERGY in the form 
of LIGHT and HEAT. At the same time, it goes 
into CHEMICAL REACTIONS that reveal what 
it is made of. 

As you enter the study of chemistry, you can do 
no better than to repeat for yourself some of the 
experiments that Mr. Faraday demonstrated to his 
young audience. 



MAKE A GAS WORKS 
FROM A CANDLE BY 
HOLDING A GLASS 
TUBE, DRAWN TO A 
POINT, IN THE FLAME 
AND LIGHTING THE 
VAPORS AT THE END 
OF TUBE. 




YOU CAN PROVE IN SEVERAL 
WAYS THAT THE FLAME OF A 
CANDLE CONSISTS OF BURNING 
PARAFFIN VAPORS. 

BLOW OUT THE CANDLE, THEN 
QUICKLY BRING A LIGHTED 
MATCH INTO THE VAPORS. 
CANDLE IS AGAIN IGNITED. 




YOU CAN ACTUALLY LEAD 
THE VAPORS FROM A BURN- 
ING CANDLE THROUGH A 
BENT GLASS TUBE INTO A 
WATER GLASS. IF LEFT 
ALONE, WHITISH VAPORS 
CONDENSE INTO A SOLID. 




18 





CANDLE CONTAINS 
HYDROGEN 



\ 



A CANDLE FORMS WATER WHEN IT BURNS. ONLY 
HYDROGEN BURNING IN OXYGEN FORMS WATER. 

1 ) HOLD A COLD GLASS FOR A FEW MOMENTS OVER 
A"BURNING CANDLE. DEW FORMS ON THE INSIDE. 

2 BY WIPING FINGER INSIDE THE GLASS YOU CAN 
MAKE DEW FLOW TOGETHER INTO WATER DROPS. 




CANDLE CONTAINS CARBON 



PLACE PIECE OF WIRE 
SCREENING OVER 
FLAME. SCREENING 
COOLS THE FLAME 
AND SOOT FORMS. 
THE SOOT IS CARBON. 



WHAT PART OF THE 
FLAME IS HOTTEST? 
TO FIND OUT, PUSH 





' C 



ii 



CRUSH A FEW ICE CUBES 
AND SPRINKLE THEM WITH 
SALT. WRAP IN ALUMINUM 
FOIL. HOLD OVER BURNING 
CANDLE. WATER DROPS WILL 
FORM ON THE OUTSIDE OF 
THE FOIL. 



PIECE OF CARDBOARD SIDEWAYS INTO FLAME. 
OUTSIDE OF FLAME SCORCHES A SOOTY RING. 



r\ 



ANOTHER WAY 
TO SHOW THAT 
CANDLE CON- 
TAINS CARBON 
IS TO PROVE 
THAT CARBON 
DIOXIDE IS 
FORMED WHEN 
CANDLE BURNS. 




WHAT YOU FOUND OUT 

HEAT 

(1,000° C) 

wafer 
vapor 
(H 2 0) 



LIGHT 
(1 candle- 
power) 



PLACE FUNNEL OVER FLAME. HOLD 
JHTED MATCH IN HOT AIR FROM FLAME. 
MATCH GOES OUT IN THIS AIR. 

(2 '■ PLACE TEST TUBE OVER FUNNEL AND 
COLLECT HOT AIR. POUR LIME WATER INTO 
TUBE AND SHAKE. LIME WATER GETS 
CLOUDY FROM CARBON DIOXIDE. 



19 




carbon 

dioxide 

(CO,) 

glowing 

carbon 

particles 

burning 
I carbon 
/ monoxide 
i /*-(CO) 

^ GAS-LIKE 
7 , ~ VAPOR 



capillary 
action 

LIQUID 



SOLID 




^^m 




Y 



on — C 

In 1896. a young Polish chemist, Marie Curie, and 
her French husband, Pierre, decided to find out why 
a certain uranium ore called pitchblende gave off 
rays that were much stronger than the uranium con- 
tent of the ore could explain. 

They secured a whole ton of powdered ore from 
a mine in northern Bohemia and set to work. First 
the powder had to be boiled with strong acids to 
extract the mysterious substance hidden in it. Then 
the solution had to be filtered and boiled down. 



tist ! 



>cien 

What remained had to be purified by various proc- 
esses which the Curies had to invent themselves. 

After two years of back-breaking work they reach- 
ed their goal. One night they went to the shed in 
which they had been working. They opened the door 
and stepped in without putting on the lights. All 
around them, the containers that held the solutions 
of the new substance glowed in the dark! They had 
discovered a new element — radium — a million 
times more active than uranium. 




SOLUTION— STIR WATER INTO THE 
MIXTURE OF SALT AND DIRT. THE WA- 
TER WILL DISSOLVE THE SALT BUT NOT 
THE DIRT. YOU NOW HAVE THE SALT 
IN "WATERY SOLUTION." 



DECANTATION — LET DIRT-MIXED 
SALT SOLUTION STAND UNTIL MOST 
OF THE DIRT HAS SETTLED. THEN POUR 
OFF THE LIQUID. THIS PROCESS IS 
CALLED "DECANTATION." 



open and 
place in funnel 



FILTRATION 1 — THE LIQUID IS PROB- 
ABLY STILL MURKY. TO CLEAR IT, IT 
NEEDS TO BE FILTERED BY LETTING IT 
RUN THROUGH FILTER PAPER (PAPER 
TOWELING WILL DO). 



20 



Why tell again the story of the discovery of 
radium? Because it contains all the features that 
show the nature of the true scientist. 

Curiosity first. The Curies were curious about the 
mystery that lay in that greyish-black powder. They 
became obsessed with a desire to find out — not in 
the hope of gaining money or fame but to establish 
a scientific truth. 

Before starting their work, the Curies gathered all 
the known facts about the material with which they 
were to work. To this knowledge they added their 
own imagination, figuring out the method they had 
to use to arrive at the result they were seeking. 

For the next two years they literally slaved in the 
drafty shed that was their laboratory. 

After they had made their discovery, the Curies 
made their method of extracting radium known to 
the world so that other scientists could check and 
test what they had done. 

As an example of the scientific method the Curies 
used, let us follow in their footsteps — but with a 
much simpler problem: 



1 MIX THOROUGHLY ONE TABLESPOON OF DIRT AND 
ONE TEASPOON OF ORDINARY TABLE SALT. NOW DE- 
CIDE THAT YOU WANT TO EXTRACT THE SALT FROM THIS 
MIXTURE AS EARNESTLY AS THE CURIES DECIDED TO EX- 
TRACT THE MYSTERIOUS SUBSTANCE FROM PITCHBLENDE 
—WITH THE EXCEPTION THAT YOU KNOW WHAT YOU 
ARE AFTER. 

2 GET THE FACTS TOGETHER. DIRT IS "DIRTY," SALT IS 
WHITE. DIRT PARTICLES ARE OF MANY DIFFERENT SHAPES, 
SALT CONSISTS OF TINY CUBES. DIRT DOES NOT DISSOLVE 
IN WATER, SALT DOES. 

3 NEXT FIGURE OUT A SUITABLE WAY OF SEPARATING 
THE TWO SUBSTANCES. ON THE BASIS OF WHAT YOU 
KNOW YOU SHOULD BE ABLE TO SEPARATE THEM WITH 
A PAIR OF TINY TWEEZERS — BUT IT WOULD PROBABLY 
TAKE YOU A YEAR TO DO IT. OR YOU COULD DISSOLVE 
THE SALT IN WATER AND SEPARATE THE SOLUTION FROM 
THE INSOLUBLE DIRT. 

4 YOU DECIDE ON THE SECOND WAY, USING THE 
STEPS SHOWN ON THE BOTTOM OF THESE PAGES. IN 
DOING THIS, YOU DO WHAT THE CURIES DID IN EX- 
TRACTING RADIUM AND LEARN, IN THE PROCESS, THE 
IMPORTANT LABORATORY TECHNIQUES OF SOLUTION, 
DECANTATION, FILTRATION, EVAPORATION, AND CRYS- 
TALLIZATION. 

5 FINALLY, YOU CHECK THE RESULT. THE WHITE SUB- 
STANCE LEFT AFTER EVAPORATION SHOULD BE SALT- 
BUT IS IT? IT LOOKS LIKE SALT. IT TASTES LIKE SALT. BY 
CHEMICAL TESTS YOU CAN PROVE THAT IT IS SALT. 



By using the same procedure in all other experi- 
ments in this book you are learning the methods 
that real scientists follow in their work — you are 
becoming a scientist yourself. 




FILTRATION 2 — FOLD FILTER PAPER 
AS SHOWN ON OPPOSITE PAGE AND 
FIT IT IN FUNNEL. POUR LIQUID ONTO 
FILTER PAPER. CLEARED LIQUID IS 
CALLED "FILTRATE." 



EVAPORATION— THE FILTRATE CON- 
TAINS THE SALT. THE SALT CAN NOW 
BE FREED BY REMOVING THE WATER 
BY BOILING IT AWAY. THIS IS KNOWN 
AS "EVAPORATION." 



CRYSTALLIZATION— AS WATER IS 
REMOVED, THERE IS TOO LITTLE OF 
IT LEFT FOR THE SALT TO STAY IN 
SOLUTION. THE SALT MAKES ITS AP- 
PEARANCE AS TINY CRYSTALS. 



21 



WATER AS A GAS 




WATER AS 
. A LIQUID 






JQ/IemeB-ts, Oompounds, and. -Mixfures 



In all your experiments in chemistry, you will be 
dealing with "matter." 

Matter is anything that takes up room and has 
weight (or "mass"). An iron bar is matter — it takes 
up room and is heavy, as you very well know. Water 
is matter — * it takes up room when you fill a pail 
with it, and a full pail weighs plenty. The air around 
you is matter — it takes up lots of room : it may not 
seem very heavy, yet the earth's atmosphere presses 
down on every square inch of your body with a 
weight of almost fifteen pounds. 

Matter has three distinct forms. Iron, for in- 
stance, is a SOLID. Water is a LIQUID. Air has 
the form of a GAS. 

If you should take iron and divide it again and 

TWO ELEMENTS AND A MIXTURE 




again until you couldn't divide it any further, every 
tiny particle would still be iron. A thing that consists 
of one kind of matter only is called an ELEMENT. 

Take water, on the other hand. You will learn to 
break water up into two kinds of matter — each of 
them an element. A thing in which two or more ele- 
ments are combined chemically is called a COM- 
POUND. In a compound the proportions of the dif- 
ferent elements that make it up are always exactly 
the same. 

Air also consists of different kinds of matter, but 
they are not combined chemically — they are simply 
mixed together. When you make a MIXTURE, you 
can mix the ingredients together in any proportions 
that suit you. 

MAKING A COMPOUND 



MIX TOGETHER 2 g OF FtOWERS OF SUtFUR 

AND 3.5 g OF IRON FILINGS. PLACE MIXTURE 

IN A DAMAGED TEST TUBE. HEAT. SHORTLY 

A CHEMICAL REACTION TAKES PLACE. 

THE MIXTURE GLOWS AND BLACK 

IRON SULFIDE FORMS. THIS 

CANNOT BE SEPARATED 

INTO SULFUR AND IRON 

AS IN PREVIOUS 

TESTS. 



sulfur- 
iron -S 

mixture 




v£2' sulfur 
"tL. is left 



POWDERED SULFUR AND IRON CAN BE MIXED 
TOGETHER IN ANY PROPORTIONS AND 
AGAIN SEPARATED. 

\\) DRAG A MAGNET THROUGH THE SULFUR-IRON MIXTURE. 
THE MAGNET WILL PICK UP THE IRON PARTICLES. 

(2) POUR HYDROCHLORIC ACID ON SOME OF THE MIXTURE 
IN A TEST TUBE. IRON DISSOLVES, SULFUR DOES NOT. 

22 




ELEMENTS ARE SUBSTANCES THAT CONSIST OF ONE METALS, METALLOIDS (METAL-LIKE), NONMETALS. SEV- 
KIND OF MATTER ONLY. THEY CAN BE DIVIDED INTO ERAL OF THE NONMETALS ARE GASES. 



METALS 




copper 



METALLOIDS 



antimony ^/J^t 



boron 



silicon 



NONMETALS 




iodine 



COMPOUNDS — INORGANIC. ALL COMPOUNDS COMPOUNDS (WITH A FEW EXCEPTIONS) ARE THOSE 
CONSIST OF TWO OR MORE ELEMENTS. INORGANIC THAT DO NOT CONTAIN THE ELEMENT CARBON. 



ACIDS 




BASES 




SALTS 




OTHERS 




CARBON COMPOUNDS ORGANIC. ORIGINALLY, ANIMALS) WERE CALLED "ORGANIC." TODAY ORGAN- 
COMPOUNDS MADE BY LIVING THINGS (PLANTS AND IC CHEMISTRY COVERS THE CARBON COMPOUNDS. 



HYDROCARBONS, ALCOHOLS, ORGANIC ACIDS, ETC. 

6=t 




vitamins 



"KROSEflE 



MIXTURES CAN CONSIST OF ELEMENTS OR COM- LOIDS) CONTAIN TINY PARTICLES. STILL OTHERS (SO- 
POUNDS. SOME MIXTURES ARE COARSE. SOME (COL- LUTIONS) ARE OF SAME STRUCTURE THROUGHOUT. 



GRAINY MIXTURES 




COLLOIDS 



SOLUTIONS 




23 




WATER CYCLE 



Evaporation from ocean 




'•^ Rain 

Evaporation 
from vegetation 
fr, j* 4 Evaporation 



-.JS /^Tft\V If/' 




H,0™ 



WATER 

olecular 
weight 1 8. 
Has density of 1 . 
Colorless, taste- 
less and odorless 
liquid. Boils at 
sea level at 100° 
Centigrade (21 2° 
Fahrenheit). 
Freezes at 0° C 
(32° Fohrenheit). 



vv at er — Our M.osf Important Oompoitmd 



Yes. water is the most important of all chemical 
compounds. Without it. there would be no life — all 
human beings and all animals would thirst to death, 
and all plant life would wilt and die. 

Fortunately, water is also the most common com- 
pound in the world. Almost three quarters of the 
earth's surface is covered by water. This water is 
forever traveling. It is turned into invisible vapor 
by evaporation from oceans and lakes and growing 

WATER AS A SOLVENT 

THE MOST IMPORTANT FUNCTION OF WATER IN 
CHEMICAL EXPERIMENTS IS AS A SOLVENT — 
THAT IS, A LIQUID IN WHICH CHEMICALS MAY 
BE DISSOLVED. FIND OUT BY AN EASY EXPERI- 
MENT WHETHER HEATING THE WATER HELPS IN 
DISSOLVING A CHEMICAL. 



1 DROP 1 TABLE- 
SPOON WASHING 
SODA IN Vi GLASS 
OF COLD WATER. 
STIR. PART OF THE 
SODA DISSOLVES 
SLOWLY. 

• 2 REPEAT WITH 
HOT WATER. SODA 
DISSOLVES QUICKLY. 
HOT WATER IS USU- 
ALLY FASTER THAN 
COLD FOR PREPAR- 
ING A SOLUTION. 



things. When cooled, the vapor forms clouds of tiny 
water drops. Further cooling makes the drops fall 
to earth as rain or snow that fill up rivers and lakes 
and oceans and continue the water cycle. 

Chemists use nature's method to produce chem- 
ically pure water. They turn ordinary tap water in- 
to steam by boiling, then turn the steam back into 
water by cooling. This process is called distillation 
and the water is called distilled water. 



WATER AS A CATALYST 

WATER HELPS BRING ABOUT MANY 
CHEMICAL REACTIONS WITHOUT IT- 
SELF ENTERING INTO THEM. A SUB- 
STANCE THAT ACTS THIS WAY IS 
CALLED A CATALYST. 




cold water 



hot water 





1 PLACE 1 TEASPOON DRY BAKING 
POWDER IN SMALL JAR. ATTACH WIRE TO 
CANDLE. LIGHT CANDLE AND LOWER IT 
INTO JAR. CANDLE GOES ON BURNING. 

! NOW POUR WARAA WATER ON THE 
BAKING POWDER. A CHEMICAL REACTION 
MAKES THE POWDER FOAM. THE GAS RE- 
LEASED IS CARBON DIOXIDE. IT MAKES 
CANDLE FLAME FLICKER AND GO OUT. 



24 



ELECTROLYSIS OF WATER 

ELECTRICITY CAN BE USED TO BREAK WATER APART 
INTO THE TWO ELEMENTS OF WHICH IT CONSISTS 
—THE GASES HYDROGEN AND OXYGEN. 
YOU CAN GET THE REQUIRED ELECTRICITY FROM THREE 
OR FOUR ORDINARY FLASHLIGHT BATTERIES. YOU WILL 
ALSO NEED TV/O PIECES OF INSULATED COPPER WIRE 
AND TWO "ELECTRODES" MADE FROM CARBON RODS. 

Making Electrodes 

1 SCORE THE MIDDLE OF THE 
CARBON ROD FROM AN OLD 
FLASHLIGHT BATTERY, USING 
A FILE. BREAK THE ROD INTO 
TV/O PIECES. 




MATERIALS FOR EXPERIMENTS 

AN ORDINARY FLASHLIGHT BATTERY WILL GIVE 
YOU MATERIALS YOU NEED FOR EXPERIMENTS 
ON THIS AND SEVERAL FOLLOWING PAGES. 




2 



carbon rod 

2 BARE THE WIRE FOR 2" 
AT EACH END OF TWO 18" 
LENGTHS OF INSULATED V/IRE. 
TIE ONE BARED WIRE AROUND 
END OF EACH OF CARBON 
ROD HALVES. 



insula 



3 BIND ELECTRI- 
CIAN'S TAPE FIRMLY 
AROUND CARBON 
RODS SO THAT NO 
WIRE IS EXPOSED. 



r~\ 





electrician's tape 



fag's electrici 



Setting up Electrolysis 

WATER IS A POOR CONDUC- 
TOR OF ELECTRICITY— SO YOU 
DISSOLVE 1 TABLESPOON OF 
WASHING SODA IN 1 PINT OF 
WATER AND FILL A WATER 
GLASS AND TWO TEST TUBES 
WITH THIS SOLUTION. THEN 
SET UP THE APPARATUS AS 
SHOWN AT RIGHT. 




1 OPEN UP BATTERY CASE CAREFULLY WITH A 
CAN OPENER AND CLEAN THE ZINC CASING. 

2 SCRAPE CARBON ROD CLEAN WITH DULL KNIFE. 

3 DRY OUT THE MOIST BLACK POV/DER, V/HICH 
IS MOSTLY MANGANESE DIOXIDE. STORE IN JAR. 
THROW REMAINING PARTS OF THE BATTERY AWAY. 



Performing the Electrolysis 

1 SLIP THE TOP OF A CARBON ELECTRODE UP 
INTO EACH OF THE TWO TEST TUBES. 

2 BIND THREE— OR, BETTER, FOUR— FLASHLIGHT 
BATTERIES TOGETHER WITH ADHESIVE TAPE, TOP 
OF ONE TOUCHING BOTTOM OF THE NEXT. 

3 WITH ADHESIVE TAPE FASTEN THE BARED END 
OF THE WIRE LEADING FROM ONE CARBON ROD 
ELECTRODE TO THE TOP OF THE FIRST BATTERY. 

4 TAPE THE BARED END OF THE WIRE FROM THE 
OTHER ELECTRODE TO BOTTOM OF LAST BATTERY. 

AS SOON AS CONNECTION IS MADE, AIR BUBBLES 
BEGIN TO COLLECT IN THE TWO TEST TUBES— 
ABOUT TWICE AS FAST IN ONE AS IN THE OTHER. 



(i '■ WITH YOUR THUMB, CLOSE THE MOUTH OF THE TEST 
TUBE FIRST FILLED WITH GAS. LIFT THE TUBE OUT OF THE 
V/ATER, MOUTH DOWN. 

2 BRING LIGHTED MATCH TO THE MOUTH OF THE TUBE. 
CONTENTS BURN WITH A SOFT "POP!" THIS IS THE TEST 
FOR HYDROGEN. 



TEST FOR 
OXYGEN 



1 WHEN SECOND TUBE IS FULL 
OF GAS, CLOSE ITS MOUTH WITH 
YOUR THUMB. LIFT THE TUBE OUT 
OF THE WATER WITH MOUTH UP. 

2 LIGHT A BROOMSTRAW. 
BLOW OUT THE FLAME. BRING 
THE GLOWING END DOWN IN 
THE TEST TUBE. GLOWING EM- 
BER BURSTS INTO BRIGHT FLAME. 
THIS IS TEST FOR OXYGEN. 



25 



OXYGEN 



AIR — 21 % OXYGEN 




I 



OXYGEN 

Element 8 . 

Atomic wt. 16. 
Colorless, odorless 
gas, supporting 
combustion (burn- 
ing). 1.1 weight of 
air. Slightly soluble 
in water — 3 vol- 
umes in 100 vol- 
umes at 20 c C. Ox- 
ygen is the most 
common element on 
earth. 



YOU — 70% OXYGEN 



L-Tl, 



"xygen — jl lie 

If you could hold your breath for a few 
minutes so that no air could get into your 
lungs, you would die. 

For thousands of years, people have 
known that no human being can live 
without air. But it was not until Karl 
Scheele, a Swedish chemist, in 1772, and 
Joseph Priestley, an Englishman, in 1774, 
discovered and described oxygen that 
people knew that it is the oxygen in the 
air that is important to life. 

Both of these scientists discovered that 
things burn more fiercely in pure oxygen 
than they do in the mixture of oxygen 
and other gases called *'air." 

In the lab. oxygen is produced by chiv- 
ing it out of certain oxygen-containing 
compounds. A good one to use in the 
home lab is hydrogen peroxide. You can 
get it at a drug store in a 3 % solution. 
Hydrogen peroxide is related to water. 

V* ater, as you know, consists of 2 parts 
of hydrogen to 1 part of oxygen. You 
could write it: Hydrogen 2— Oxygen 1. 
That's pretty much what chemists do — 
except that they abbreviate the names to 
initials, use small numbers, and don't 
bother about the number 1. The formula 
becomes H,0. 



fix of Life 



rea 

Hydrogen peroxide contains 2 parts of 
hydrogen to every 2 parts of oxygen. How 
would you write it in chemical language? 

H 2 5 ? You're perfectly right! 

H,0 2 becomes water (H 5 0) and gives 
off oxygen (0) when you throw a catalyst 
into it. For a catalyst, you can use the 
manganese dioxide from an old flashlight 
battery (page 25). 



IT'S A LONG STEP FROM THE DIS- 
COVERY OF OXYGEN IN 1772 TO 
ITS PRESENT-DAY USE IN INDUS- 
TRY AND HOSPITALS, AIRPLANES 
AND SPACE SHIPS, AND FOR SEND- 
ING SATELLITES INTO ORBIT. 



^m 








26 



THE ATMOSPHERE CONTAINS OXYGEN 

1 FASTEN A SMALL CANDLE TO MIDDLE OF 
PIE PLATE WITH CANDLE DRIPPINGS. FILL PIE 
PLATE WITH WATER. LIGHT CANDLE. PLACE 
AN EMPTY JAR OVER CANDLE. 





MAKING A SMALL AMOUNT 
OF OXYGEN 

FILL JAR '/„ FULL OF 3% HYDROGEN PER- 
OXIDE. ADD PINCH OF MANGANESE DI- 
OXIDE FROM FLASHLIGHT BATTERY (SEE 
PAGE 25). TEST FOR OXYGEN WITH 
GLOWING BROOMSTRAW EMBER GLOWS 
BRIGHTER AND MAY BURST INTO FLAME. 



MAKING OXYGEN 
THE HOME LAB 




'1 TO COLLECT OXYGEN, YOU NEED A "PNEUMATIC TROUGH." 
THIS IS A DEEP, WATER-FILLED TRAY WITH METAL "BRIDGE." 

2 FIT BOTTLE WITH STOPPER WITH L-SHAPED GLASS TUBE AND 
RUBBER TUBE LONG ENOUGH TO REACH HOLE OF BRIDGE. 

3 FILL BOTTLE >/ 4 FULL OF 3% HYDROGEN PEROXIDE. ADD 
'/g TEASPOON OF MANGANESE DIOXIDE. PUT THE STOPPER IN. 

4 FILL JAR WITH WATER AND PLACE IT UPSIDE DOWN ON THE 
BRIDGE IN SUCH A WAY THAT THE OXYGEN BUBBLES INTO IT 
AND FILLS IT BY FORCING OUT AND REPLACING THE WATER 

5 WHEN JAR IS FULL OF OXYGEN, SLIDE A GLASS PLATE UN- 
DER OPENING [OR PUT STOPPER IN IT). TURN JAR RIGHT SIDE 
UP— QUICKLY, TO PREVENT THE OXYGEN FROM ESCAPING. 

MANY MATERIALS BURN IN OXYGEN 

1 ATTACH TUFT OF STEEL WOOL TO WIRE. HEAT 
TO RED HEAT OVER ALCOHOL BURNER. LOWER INTO 
JAR OF OXYGEN. IRON BURSTS INTO FLAME. 

2 PLACE SMALL PIECE OF SULFUR IN CROOK OF 
BENT STRIP OF TIN CUT FROM CAN. IGNITE SULFUR 
WITH MATCH. LOWER INTO JAR OF OXYGEN. SUL- 
FUR BURNS WITH A BRILLIANT, BLUE LIGHT. 




oxygen is slightly 
heavier than air 
— so keep mouth 
of jar up 




"BRIDGE" FOR "PNEUMAT- 
IC TROUGH" MADE FROM 
2y 2 " STRIP OF TIN CAN. 



27 









fc-H "I :-v . 








HENRY CAVENDISH, WHO DIS- 
COVERED HYDROGEN IN 1766, 
HAD NO IDEA OF THE ASTON- 
ISHING FORCE OF HYDROGEN 
WHEN RELEASED IN A BOMB. 



ydrogen — Lightest oi 



Hydrogen is the lightest element in existence — Yn 
the weight of air. For this reason one of its early 
uses was for filling balloons. The first man-carrying 
gas balloon was sent up by the Frenchman, Jacques 
Charles, in 1783. The danger of using an explosive 
gas for this purpose was demonstrated in 1937 in 
the Hindenburg disaster, when the hydrogen-filled 
Zeppelin dirigible exploded on arriving at Lakehurst. 
New Jersey, after a trip across the Atlantic Ocean. 
Thirty-six people lost their lives. 

Hydrogen is one of the most important of all the 
elements. It is found in all living things — your own 
body is approximately 10 per cent hydrogen. Water, 
as you know, is part hydrogen. So is the food you 
eat, the milk you drink, the clothes you wear, and 
such common, everyday things as gasoline and fuel 
oil and cooking gas. 

In the home lab, you can make hydrogen by add- 
ing strips of zinc from a flashlight battery to hydro- 
chloric acid which consists of hydrogen (H) and 
another gas called chlorine (CI). The zinc forms a 
compound (ZnCl,) with the chlorine and sets the 
hydrogen free (II 8 ). 




HYDROGEN FORMS WATER WHEN IT BURNS 

1 FILL TEST TUBE % FULL OF HYDRO- CHLORIC ACID. ADD A COUPLE 
OF ZINC STRIPS. BUBBLES OF HYDROGEN FORM IMMEDIATELY. 

2 CLOSE TEST TUBE WITH RUBBER STOPPER WITH GLASS TUBE 
DRAWN TO JET POINT. COVER APPARATUS WITH A TOWEL. 

3 PLACE EMPTY TEST TUBE OVER GLASS TUBE. AFTER 1 MINUTE, 
TEST THIS TUBE FOR HYDROGEN WITH LIGHTED MATCH. IF TUBE 
"BARKS," PUT IT BACK. AFTER ANOTHER MINUTE, TRY AGAIN. WHEN 
SOFT "POP" TELLS YOU GAS IS PURE, LIGHT JET. 

4 HOLD A COLD GLASS OVER HYDROGEN FLAME. DEW COVERING 
THE INSIDE OF THE GLASS SHOWS THAT WATER IS FORMING. 



HYDROGEN IS LIGHTEST 
GAS KNOWN 

1 ' FILL A POP BOTTLE Vi FULL OF HALF- 
AND-HALF MIXTURE OF HYDROCHLORIC 
ACID AND WATER. DROP IN HALF A DOZEN 
ZINC STRIPS. LET NO FLAME COME NEAR! 

2 ; FIT BALLOON ON MOUTH OF BOTTLE. 

3 WHEN BALLOON IS INFLATED, TIE 
OPENING WITH STRING AND REMOVE 
FROM BOTTLE. IF PERMITTED, BALLOON 
WILL RISE TO CEILING INDOORS. OUT- 
DOORS, IT WILL SOAR UP IN THE SKY. 




28 



MAKING HYDROGEN 

1 MAKE THE SAFETY GAS GENER- 
ATOR DESCRIBED ON PAGE 1 2. 




H HYDROGEN 
Element 1 . 
At. wt. 1.008 
Colorless, odorless 
and combustible 
gas. Highly explo- 
sive in mixtures 
with air. 1/14 
weight of air. 
Slightly soluble in 
water — 1 .8 vol- 
umes in 100 vol- 
umes at 20° C. 



6 CLOSE TUBE OF BOTTLE A WITH CLOTHESPIN. 

7 AS SOON AS HYDROGEN STARTS TO BUBBLE UP THROUGH WATER 
IN PNEUMATIC TROUGH, COLLECT SOME IN WATER-FILLED TEST TUBE. 
WHEN FULL OF GAS, TEST IT AS DESCRIBED AT BOTTOM OF PAGE. WHEN 
HYDROGEN IS PURE, BUBBLE IT INTO UPSIDE-DOWN, WATER-FILLED JARS. 

8 WHEN YOU HAVE MADE THE EXPERIMENTS YOU WANT, CHANGE 
SPRING CLOTHESPIN FROM RUBBER TUBE OF BOTTLE A TO RUBBER TUBE 
OF BOTTLE B. HYDROGEN FORCES ACID FROM BOTTLE B BACK INTO A. 
WHEN ACID NO LONGER TOUCHES ZINC, REACTION STOPS. 



PLAYING SAFE WITH HYDROGEN 

IN MIXTURES WITH AIR, HYDROGEN IS HIGHLY 
EXPLOSIVE. FOLLOW SAFETY RULES BELOW. 

• MAKE ONLY SMALL AMOUNTS OF HYDRO- 
GEN IN THE HOME LAB. A 4-OZ. GENERATOR 
BOTTLE WILL GIVE YOU ALL THE HYDROGEN 
YOU NEED. MAKE ALL CONNECTIONS AIRTIGHT. 

• TEST HYDROGEN FOR PURITY BY COLLECTING 
A TEST TUBE FULL OF IT AND BRINGING A LIGHT- 
ED MATCH TO MOUTH OF TUBE, AS SHOWN 
ON PAGE 25. HYDROGEN MIXED WITH AIR EX- 
PLODES WITH A SHARP "BARK." PURE HYDRO- 
GEN BURNS WITH A QUIET "POP." 

• KEEP FLAME AWAY FROM YOUR MAIN GEN- 
ERATOR BOTTLE. 

• IGNITE HYDROGEN ONLY FROM TEST TUBE 
GENERATOR DESCRIBED ON OPPOSITE PAGE, 
AND THEN ONLY AFTER YOU HAVE TESTED IT 
FOR PURITY. 




WHEN YOU KNOW FROM TESTING SAM- 
PLES OF GAS COLLECTED IN TEST TUBES 
THAT HYDROGEN IS PURE, FILL SMALL JAR 
WITH IT. LIFT JAR OUT OF WATER, MOUTH 
DOWN. BRING LIGHTED CANDLE UP INTO 
JAR. HYDROGEN BURNS AT MOUTH OF 
JAR. CANDLE GOES OUT. 



29 



ODcj 



INHALE 
OXYGEN 



« EXHAIE 

V CARBON 

' V. DIOXIDE 

r - 




GIVE 

OFF 

OXYGEN 



TAKE IN 
CARBON 
DIOXIDE 






LIQUID CARBON DIOX- 
IDE IS USED IN FIRE EX- 
TINGUISHERS. 




Oar ton Dioxide 

1 ou hate already learned in experimenting with a 
burning candle that when something containing car- 
bon burns in the air, a gas, carbon dioxide (CO,), 
is formed. This is one of the most important gases 
for human life. The reason is that green plants, in 
sunlight, are able to take the carbon out of the car- 
bon dioxide in the air and, by combining it with 
oxygen and hydrogen from water and with various 
minerals in the soil, produce all the vegetable matter 
that humans and animals eat. 

\ou cannot see the C0 2 in the air — but you can 
see it when it has been cooled and compressed into 
a solid block of "dry ice." When dissolved in water 
(H 2 0), carbon dioxide (C0 2 ) forms a weak acid 
(H 2 COj). Yon know the taste of this acid from soda 
water — the bubbles are CO* being set free. 

Carbonic acid combines with many metals to 
make "carbonates." You can drive the C0 2 out of 
most carbonates with the help of a weak acid — even 
with vinegar, which is diluted acetic acid. 

MAKING A FIRE EXTINGUISHER MODEL 




1 PUSH A SHORT GLASS TUBE 
WITH A JET TIP INTO A RUBBER 
STOPPER. WRAP BICARBONATE OF 
SODA IN A SHEET OF TOILET TISSUE. 
ATTACH SODA PACKAGE TO TUBE 
WITH A RUBBER BAND. 



2 FILL BOTTLE HALF FULL OF MIXTURE OF 1 PART VINE- 
GAR AND 1 PART WATER. PUT IN THE STOPPER. 



CHEMICAL FIRE EXTINGUISHERS 
CONTAIN SOLUTION OF BAKING 
SODA AND A BOTTLE OF SUL- 
FURIC ACID. WHEN TURNED UP- 
SIDE DOWN, THE CHEMICALS MIX 
AND FORM CARBON DIOXIDE 
WHICH FORCES OUT THE WATER. 





HOLD STOPPER FIRM- 
LY IN PLACE WITH TWO 
FINGERS. TURN BOTTLE 
UPSIDE DOWN. THE CO, 
FORMED BY MIXING 
VINEGAR AND SODA 
DRIVES WATER OUT IN 
POWERFUL JET. 



30 



CO, 



CARBON 
DIOXIDE 

Compound • 

Molecular wt. 44. 
Colorless, odorless 
gas. Does not burn. 
Does not support 
combustion (burning 
1.529 weight of oir. 
Fairly soluble in wa- 
ter — 88 volumes in 
100 volumes at 20° C. 



FEATURES OF CARBON DIOXIDE 

CO, IS HEAVIER THAN AIR AND 
DOES NOT SUPPORT BURNING. 
YOU CAN PROVE BOTH POINTS: 



MAKING 

LIME 

WATER 





( 1 ' PLACE 1 TEASPOON OF BAKING SODA IN A PITCHER. POUR 
A SMALL AMOUNT OF WHITE VINEGAR OVER THE SODA. 

f| HANG A LIGHTED CANDLE IN A JAR BY A WIRE. POUR THE 
ARBON DIOXIDE FORMED IN THE PITCHER INTO THE JAR THE 
WAY YOU WOULD POUR WATER. WHEN THE CARBON DIOXIDE 
REACHES THE TOP OF THE CANDLE, THE FLAME GOES OUT. 



MAKING C0 2 



<\> STIR 1 TEASPOON OF 
HYDRATED LIME INTO 
1 PINT OF WATER. 

(£) LET STAND UNTIL LIME SINKS TO THE 
BOTTOM. FILTER LIQUID INTO A BOTTLE. 
CLOSE BOTTLE TIGHTLY. 



BURNING PRODUCES CARBON DIOXIDE 

HANG BURNING CANDLE IN JAR CONTAINING A 
FEW ml LIME WATER. COVER TOP WITH A GLASS 
PLATE. WHEN CANDLE HAS GONE OUT, SHAKE 
LIME WATER UP WITH THE AIR. MILKINESS PROVES 
THAT C0 2 HAS BEEN PRODUCED. 




IN LABORATORY, CARBON DIOXIDE IS USUALLY MADE 
FROM MARBLE CHIPS AND DILUTED HYDROCHLORIC 
ACID (1 PART ACID TO 1 PART WATER). PLACE CHIPS 
ON TOP OF PEBBLES IN YOUR GAS GENERATOR, THEN 
PROCEED AS FOR MAKING HYDROGEN (PAGE 29). 



BREATHING PRODUCES CO, 

BREATHE THROUGH GLASS TUBE INTO 
LIME WATER IN TEST TUBE. LIME WATER 
GETS MILKY. THIS SHOWS THAT BREATH- 
ING IS A BURNING PROCESS. 



31 




NITROGEN 

Element 7. 

At. wt. 14.008. 
Colorless, odorless 
gas. Does not burn. 
Does not support 
combustion (burn- 
ing). .967 weight 
of air. Slightly sol- 
uble in water — 1.5 
volumes in 100 
vols, at 20°C. 



^^ r i?S^^^^^§'-Nittrogeii audits Oonipoiuids 




NITROGEN FROM THE ATMOSPHERE 

1% RARE GASES:" 



78% NITROGEN 



21 % OXYGEN 



•ARGON 

NEON 
KRYPTON 
XENON 
HELIUM 
AISO: COi, 



HiO 



REPEAT CANDLE-BURNING EXPERIMENT ON PAGE 27. 
UNUSED GAS IS ALMOST ALL NITROGEN — WITH SMALL 
PERCENTAGE OF RARE GASES AND CARBON DIOXIDE. 



NITROGEN DIOXIDE 

IN A WEIL-VENTILATED 
ROOM. HEAT EQUAL 
AMOUNTS OF SALTPETER 
AND SODIUM BISULFATE 
IN DRY TEST TUBE. IN A 
MOMENT, A BROWN GAS 
FORMS. IT IS NITROGEN 
DIOXIDE. DO NOT INHALE 
—GAS IS VERY IRRITATING. 




When you burn anything in Lhe air, only about one- 
fifth of the ah goes into chemical combination with 
what you are burning. The rest (except for a small 
fraction) does not enter into the process. It is a gas 
called nitrogen (N) — the most abundant free ele- 
ment on earth. 

Nitrogen is what you might call a "lazy" element. 
It does not help in burning nor does it burn if you 
try to ignite it. It is only at high temperatures and 
under great pressures that a chemist can make ni- 
trogen combine with another element, hydrogen, to 
form ammonia gas (XII,), from which other nitrogen 
compounds can be made. 

\ et. in nature, tiny bacteria on the roots of cer- 
tain plants can take nitrogen from the ah and make 
it combine with oxygen and minerals in the soil into 
"'nitrates." And that is of tremendous importance to 
all of us — for all plants need nitrates if they are to 
thrive. If plants do not get nitrates naturally, the 
farmer must add them to his soil in the form of some 
kind of fertilizer. 

\ ou will not have much satisfaction out of work- 
ing with nitrogen itself, but you will find it inter- 
esting to deal with some of its compounds — espe- 
cially with ammonia gas (XH 3 ). You will also want 
to have a look at one of the half dozen combinations 
nitrogen makes with oxygen, the brown gas called 
nitrogen dioxide (NO,). 



32 



AMMONIA 

IjVj [ffln Compound. 
Molecular 
weight 17. Color- 
less gas with 
strong, penetrating 
odor. .596 weight 
of air. Highly sol- 
uble in water — 
70,000 vols, in 100 
vols, ot 20°C. 




PRODUCING AMMONIA 

SIMPLEST WAY OF PRODUCING 
AMMONIA IS TO GET IT FROM ITS 
SOLUTION AS HOUSEHOLD AM- 
MONIA. 

FILL PINT CAN ONE QUARTER FULL OF 
HOUSEHOLD AMMONIA. FIT STOPPER 
WITH 6" GLASS TUBE IN OPENING. 
PLACE TEST TUBE OVER GLASS TUBE. 
HEAT CAN OVER LOW FLAME. TEST 
TUBE IS FULL OF AMMONIA V/HEN 
MOIST, RED LITMUS PAPER HELD AT 
ITS MOUTH TURNS BLUE. 



SOLUBILITY OF 
AMMONIA 

REMOVE A FILLED 
TEST TUBE FROM 
GAS GENERATOR 
CAN, MOUTH 
DOWN. CLOSE 
MOUTH OF TUBE 
WITH THUMB. OPEN 
TUBE UNDER WA- 
TER. AMMONIA DIS- 
SOLVES EASILY, 
WATER RUSHES IN 
AND FILLS TUBE. 




p 

1 





MAKING AMMONIA FROM 
SAL AMMONIAC 



/MOIST, RED 
LITMUS PAPER 
TURNS BLUE 
IN AMMONIA. 



I ON A PIECE OF PAPER, MIX 1 PART OF SAL AMMO- 
NfAC WITH 2 PARTS OF HYDRATED LIME. ADD A FEW 
DROPS OF WATER. DROP MIXTURE INTO A TEST TUBE. 
PROVIDE TUBE WITH STOPPER AND L-SHAPED GLASS 
TUBE. THEN HEAT OVER LOW FLAME. 

2 : COLLECT AMMONIA IN DRY TEST TUBE. TEST IT WITH 
LITMUS PAPER AND FOR SOLUBILITY. 




THE AMMONIA FOUNTAIN 

AMMONIA'S EXTRAORDINARY SOLUBILITY CAN BE 
SHOWN IN A SPECTACULAR DEMONSTRATION. 

1 i MAKE UP APPARATUS AS SHOWN IN ILLUSTRATION. 
FILL IT WITH WATER. ADD 5 DROPS OF PHENOLPHTHAL- 
EIN SOLUTION. 

('£) FILL DRY, EMPTY BOTTLE WITH AMMONIA FROM 
GENERATOR CAN. KEEPING BOTTLE UPSIDE DOWN, 
PLACE IT FIRMLY ON TOP STOPPER OF APPARATUS. 

3 BLOW INTO L-SHAPED GLASS TUBE TO DRIVE A FEW 
DROPS OF WATER UP INTO THE UPPER BOTTLE. 

4 SUDDENLY, WATER SPURTS FROM LOWER BOTTLE 
UP INTO UPPER BOTTLE IN A FOUNTAIN THAT TURNS 
PINK AS AMMONIA REACTS ON PHENOLPHTHAIEIN. 



THE WHITE SMOKE 
MYSTERY 

i) MOISTEN INSIDE OF 
JAR WITH SMALL AMOUNT 
OF HYDROCHLORIC ACID. 
POUR EXCESS ACID BACK 
INTO ITS BOTTLE. COVER 
JAR WITH SQUARE OF 
CARDBOARD. 



FILL ANOTHER JAR WITH AMMONIA. PLACE 
UPSIDE DOWN ON CARDBOARD. 

(3 1 HOLD ON TO AMMONIA-FILLED JAR AND 
PULL CARDBOARD AWAY. IMMEDIATELY, BOTH 
JARS FILL WITH '■SMOKE" OF TINY AMMONIUM 
CHLORIDE CRYSTALS. 




33 




CHLORINE 

Element 17. 

Atomic wt. 
35.457. Green- 
ish-yellow, suffo- 
cating gas. Com- 
bines actively 
with many ele- 
ments. 2.5 weight 
of air. Fairly sol- 
-77'' ""-- uble in water — 
226 vols, in 100 
-• : - volumes at 20°C. 



Ckl 



orine 



-F 



Tieiid an 



Foe 



Chlorine is a gas of great importance. We wouldn't 
be certain of safe drinking water in our cities if it 
weren't for chlorine — a small amount of it in the 
water kills the dangerous germs that may lurk in it. 
Chlorine is also used extensively in bleaching.- 

Chlorine is a friendly gas when it is used correctly. 
But it is dangerous when used improperly because 
it affects the lungs. As a "poison gas" it caused many 
casualties in World War I. 



You can produce chlorine as a greenish-yellow gas 
by chiving it out of one of its compounds — hydro- 
chloric acid (IIC1), which consists of hydrogen (H) 
and chlorine (CI), or a common laundry bleach 
("Clorox" or others), which is a solution of sodium 
hypochlorite (NaCIO). 

Have a bottle of diluted household ammonia (90% 
water, 10% household ammonia) on hand. Sniff this 
if you get too strong a whiff of chlorine. 



NOTE: Perform these experiments out-of-doors or be- 
fore an open window. Be careful not to breathe fumes. 



MAKING TEST PAPER 
FOR CHLORINE 




MIX .5 g (Vi TEASPOON) STARCH WITH 30 ml 
WATER. BRING TO BOIL DISSOLVE IN MIXTURE 
A SMALL AMOUNT OF POTASSIUM IODIDE (AS 
MUCH AS TWO GRAINS OF RICE). DIP STRIPS 
OF FILTER PAPER IN MIXTURE; THEN DRY THEM. 



CHLORINE FROM 
HYDROCHLORIC ACID 




£Put .5 g [Va TEASPOON) MANGANESE DIOXIDE INTO 
TEST TUBE. ADD 3 ml (% TEST TUBE) UNDILUTED HYDRO- 
CHLORIC ACID. HEAT GENTLY. CHLORINE FORMS. WAFT 
A LITTLE CAREFULLY TOWARD YOU FOR A SNIFF. 

•.a J' TEST GAS BY HOLDING MOISTENED STARCH-IODIDE 
PAPER AT MOUTH OF TUBE. PAPER TURNS BLUE. 



34 



MAKING CHLORINE IN THE HOME LAB 

1 MAKE APPARATUS SHOWN AT 
RIGHT. POUR 1 INCH OF LIQUID 
BLEACH (CLOROX) INTO BOTTLE A. 
BOTTLE B IS EMPTY. BOTTLE C HAS 
WATER IN WHICH % TEASPOON LYE 
IS DISSOLVED. 

2 TAKE STOPPER OUT 
OF BOTTLE A. DROP IN 
i/ 2 TEASPOON SODIUM 
BISULFATE (SANI-FLUSH). 
REPLACE THE STOPPER. 

3 CHLORINE GAS 
FORMS AND FILLS B. 

4 LYE WATER IN BOT- 
TLE C ABSORBS EXCESS 
OF CHLORINE GAS. 



^ 





WHEN REACTION SLOWS 
ADD MORE SODIUM BISULFATE 



EXPERIMENTS 



WITH CHLORINE 



CHLORINE REACTS 
VIGOROUSLY WITH 
MOST OTHER ELE- 
MENTS. IT IS PAR- 
TICULARLY ACTIVE 
WITH HYDROGEN 
AND MANY HYDRO- 
GEN COMPOUNDS. 



LOWER A BURNING CANDLE INTO 
A BOTTLE OF CHLORINE GAS. A 
DENSE SMOKE OF CARBON IS 
FORMED. THE CHLORINE COMBINES 
WITH THE HYDROGEN OF THE CAN- 
DLE AND SETS THE CARBON IN IT 
FREE AS SOOT. 

CHLORINE WILL COMBINE 
DIRECTLY WITH SEVERAL 
METALS. IRON ACTUALLY r'r- 
BURNS IN CHLORINE GAS! ^ 



FASTEN A SMALL WAD OF 
STEEL WOOL TO A PIECE OF 
WIRE. HEAT IT WITH A MATCH 
AND LOWER IT INTO CHLO- 
RINE-FILLED BOTTLE. A HEAVY 
BROWN SMOKE OF IRON 
CHLORIDE POURS OUT. 





NOTE: EACH TIME YOU RP 
MOVE THE GAS-COllECT- 
ING BOTTLE B FOR EXPERI- 
MENT, CONNECT BOTTLES 
A AND C TO PREVENT 
CHLORINE FROM GETTING 
OUT IN THE ROOM. 



TO SHOW THE SOLUBILITY OF CHLORINE, 
POUR A SMALL AMOUNT OF WATER INTO 
A CHLORINE-FILLED BOTTLE. CLOSE THE 
BOTTLE MOUTH WITH YOUR PALM. 
SHAKE. THE CHLORINE DISSOLVES AND 
THE BOTTLE STICKS TO YOUR PALM FROM 
THE SUCTION CREATED. 




CHLORINE HAS 
GREAT USE IN 
BLEACHING COT- 
TON AND LINEN 
AND WOOD 
PULP. YET IT IS 
NOT THE CHLO- 
RINE THAT PER- 
FORMS THE 
BLEACHING. 




-^/^-J* 




moist 



©FILL A BOTTLE WITH CHLORINE GAS. HANG 
IN IT (FROM A CORK OR FROM A PIECE OF CARD- 
BOARD) A STRIP OF DRY, BRIGHTLY COLORED COT- 
TON CLOTH. NOTHING HAPPENS. COLOR OF 
CLOTH IS NOT AFFECTED. 

(5) MOISTEN THE CLOTH AND AGAIN HANG IT 
IN THE CHLORINE. SOON THE COLORS FADE — 
ONLY TRULY "FAST" COLORS REMAIN. CHLORINE, 
IN CONTACT WITH WATER, COMBINES WITH THE 
HYDROGEN AND LIBERATES OXYGEN. THE LIB- 
ERATED OXYGEN DOES THE BLEACHING. 



35 



^ mSH^ goldy^\ tin 

ilve >^i/# 7\ 




mercury 




THE ALCHEMISTS USED FANCIFUL FIGURES TO 
REPRESENT THE CHEMICALS WITH WHICH THEY 
WORKED. 




magnesium 



sulfur hydrogen 




oxygen ammonia 



cmd _ 

carbon dioxide — 

JOHN DALTON SUGGESTED 
MARKED CIRCLES TO INDICATE 
DIFFERENT ELEMENTS. 




: "'5&* S3 tcarb °»> 




c 

carbo 






JONS JAKOB BER- 
ZELIUS DEVELOPED 
THE SYSTEM USED 
TODAY, IN WHICH 
THE NAMES OF 
ELEMENTS ARE 
ABBREVIATED. 



Ohemical DliortliaiicL 

So fab you have experimented with oxygen and 
hydrogen, carbon dioxide and nitrogen, and chlorine ; 
you have also separated water into the two ele- 
ments of which it consists, and have combined the 
two elements iron and sulfur into a chemical com- 
pound. In taking notes of your experiments you are 
certain to have learned that it is much quicker to 
write "H" than ■'hydrogen," and easier to write 
'"C0 S " than '"carbon dioxide." Before long, it will 
seem the simplest and most logical thing in the world 
to use these abbreviations of the names of the dif- 
ferent elements rather than the full names. 

Yet it took chemists hundreds of years before they 
settled on this uniform method of writing out their 
chemical formulas. 

In the early days of chemistry no one bothered to 
do much writing about it. But it became necessary 
for the alchemists to write down their experiments 
— how else could they retrace their steps in case they 
actually hit upon the gold they" were seeking? They 
invented a whole line of complicated symbols that 
only they could understand. 

As chemists delved deeper and deeper into the 
mysteries of matter it became more and more im- 
portant for them to write out their experiments in 
such a way- that all other chemists would know what 
they were trying to explain. 

The first to invent a usable system was John Dal- 
ton, an English scientist. The invention was almost 
forced upon him. 

In his study of chemistry he had become convinced 
that all chemical reactions could be explained in 
terms of the tiniest possible part of one element re- 
acting with the tiniest possible part of another. These 
particles he called '"atoms." The smallest possible 
part of the compound that resulted he called a "com- 
pound atom" — today we call it a "molecule." 

To explain his "atomic theory" Dalton made use 
of circles, each with a marking to indicate a specific 
element. These circles served to explain Dalton's 
theory- but they- were too difficult to work with to 
show complicated. chemical reactions. 

A Swedish chemist, Jons Jakob Berzelius, worked 
out a simpler system — the same system scientists 
use today. 

For his symbols he took the first letter of the Latin 
name of each element — C for "carbo," S for "sul- 
fur." Where two names started with the same letter, 
he added a small letter to one of the symbols to 



36 



distinguish the two elements from each other — he 
used Ca for "calcium." for instance, to distinguish 
it from carbon (C). 

But Berzelius went an important step further. 

By then the French chemist, Joseph Louis Proust, 
had discovered that whenever elements form com- 
pounds these are always of a very definite compo- 
sition — the '"Law of Definite Composition. 7 ' Water 
molecules, for example, always contain the same 
number of hydrogen and oxygen atoms. And Dalton 
had found that when two elements combine in dif- 
ferent ways they do this in simple proportions — the 
"Law of Multiple Proportions." One atom of carbon 
and one atom of oxygen make carbon monoxide; one 
atom of carbon and two atoms of oxygen make car- 
bon dioxide. 

To describe these things in a simple way Berzelius 
made each of his symbols stand not only for a specific 
element but also for its relative weight as compared 
to the weight of other elements — its "atomic weight." 
To show the composition of a compound he simply 
put together the symbols for the elements into a 
"formula"— CO. IIC1, FeS, and so on."CO" then not 
only meant that one atom of carbon and one atom 
of oxygen combine to make one molecule of carbon 
monoxide, but also that 12 weight units of carbon 
(12 being the atomic weight of carbon) combine with 
16 weight units of oxygen (16 being the atomic weight 
of oxygen) to form 28 weight units of the compound 
carbon monoxide. 

WTien a compound contained several atoms of the 
same element Berzelius indicated this by placing a 
number in front of the symbol. It was later found 
necessary to change this to a smaller number, called 
a "subscript," placed at the lower right of the sym- 
bol — H 2 0, CO,. 

In recent years it has been necessary" to change 
Dalton's idea of an atom as being the smallest in- 
divisible part of an element. Nowadays we have 
machines, such as the cyclotron, that can bombard, 
or "smash" atoms into still smaller parts — neutrons, 
and electrically charged protons and electrons. Ac- 
cording to today's atomic theory protons and neu- 
trons form the nucleus of the atom and electrons 
whirl around the nucleus with such tremendous 
speed that they seem to form a "shell" around it. 

But even with our new idea of an atom, Dalton's 
main theory is still useful for explaining chemical re- 
actions, and Berzelius' method is still the simplest 
"shorthand" method any scientist has ever devised 
for writing them down. 




AN ATOM MIGHT LOOK LIKE A BALL SUCH AS THIS IF 
YOU ENLARGED IT A BILLION TIMES. THE '•SHELL" IS 
NOT SOLID — IT CONSISTS OF ELECTRONS MOVING SO 
FAST THAT THEY SEEM TO FORM A SOLID SHELL 




IF YOU COULD SLOW DOWN AN ENLARGED CARBON 
ATOM YOU MIGHT SEE TWO OF ITS ELECTRONS TRAVEL- 
ING AROUND THE NUCLEUS IN AN "INNER SHELL" AND 
FOUR MORE WHIRLING AROUND IN AN "OUTER SHELL." 




IF YOU COULD HALT AN ENLARGED CARBON ATOM 
COMPLETELY, IT WOULD LOOK A LOT LIKE OUR SOLAR 
SYSTEM, WITH A "SUN" (PROTONS AND NEUTRONS) IN 
THE CENTER AND "PLANETS" (ELECTRONS) AROUND IT. 



37 




f tiie Jc/lemeiits 



H 1 

Hydrogen 
1.008 



I A 



hydrogen 



II 



oxygen 



He 



Helium 
4.003 



Ne II 

Neon 
20.183 



A 18 

Argon 
39.944 



Kr 36 

Krypton 
83.8 



Xe 54 

Xenon 
131.3 



Li 



Lithium 

6.940 



Na 11 

Sodium 
22.991 



K 19 

Potassium 
39.1 



Rb 37 

Rubidium 
85.48 



Cs 55 

Cesium 
132.91 



Be 4 

Beryllium 
9.013 




e o 

From the earliest times people have tried to explain 
what "matter" was made of. Most early philos- 
ophers agreed that "matter" was made up of what 
they called "elements." But their idea of an "ele- 
ment" was quite different from what we mean by 
that word today. 

The early Greek philosophers thought the entire 
universe was composed of only four basic substances : 
fire, earth, water, and air. This explanation made 
sense at the time and was not seriously challenged 
for many centuries. 

The old Romans actually knew nine of the sub- 
stances we call elements today. They called them, 
of course, by their Latin names (the same we use 
today in chemical symbols): carbo (carbon — C), 
sulfur (S), aurum (gold — Au), argentum (silver — 

FOR MORE THAN A THOUSAND YEARS PHILOSOPHERS 
INSISTED THAT ALL SUBSTANCES WERE MADE UP OF FOUR 
ELEMENTS: FIRE THAT WAS DRY AND HOT, EARTH THAT WAS 
HOT AND MOIST, WATER THAT WAS MOIST AND COLD, 
AIR THAT WAS COLD AND DRY. WE KNOW BETTER NOW! 



Mg 12 

Magnesium 
24.32 



Ca 20 

Calcium 
40.08 



Sr 38 

Strontium 
87.63 



Ba 56 

Barium 
137.36 



THE MODERN PICTURE OF AN ATOM HAS A NU- 
CLEUS IN THE CENTER, CONSISTING OF PRO- 
TONS (p) AND NEUTRONS (n), WITH ELECTRONS 
IN RINGS AROUND IT. 



THE PERIODIC TABLE OF THE ELEMENTS 



III A 



IV A 



V A 



VI A 



VII A 



Sc 21 

Scandium 
44.96 



Y 39 

Yttrium 
88.92 



57-71 

Lanthanons 



Ti 22 

Titanium 
47.9 



Zr 40 

Zirconium 
91.22 



Hf 72 

Hafnium 
178.50 



V 23 

Vanadium 
50.95 



Nb 41 

Niobium 
92.91 



Ta 73 

Tantalum 
180.95 



Cr 24 

Chromium 
52.01 



Mo 42 

Molybdenum 
95.95 



W 74 

Tungsten 
183.86 



Mn 25 

Manganese 
54.94 



Tc 43 

Technetium 
99 



Re 75 

Rhenium 
186.22 



Fe 26 

Iron 
55.85 



Ro 44 

Ruthenium 
101.1 



Os 



76 



Osmium 
190.2 



Rn 86 

Radon 
222 



Fr 87 

Francium 
223 



Ra 88 

Radium 
226.05 



89-103 

Aclinons 



INERT 
GASES 



ALKALI 
METALS 



ALKALINE 

EARTH 

METALS 



ROWS RUNNING FROM LEFT TO 
RIGHT ARE CALLED PERIODS. COL- 
UMNS RUNNING FROM TOP TO 
BOTTOM ARE CALLED GROUPS. THE 
ELEMENTS WITHIN A GROUP HAVE 
MANY TRAITS IN COMMON. 



La 57 

lanthanum 
138.92 



Ce 58 

Cerium 
140.13 



Pr 59 

Praseodymium 

140.92 



Nd 60 

Neodymium 
144.27 



Pm 61 

Promethium 
145 



Sm 62 

Samarium 
150.35 



Ac 89 

Actinium 
227 



Th 90 

Thorium 
232.05 



Pa 91 

Protactinium 
231 



U 92 

Uranium 
238.07 



Np 93 

Neptunium 
237 



Pu 94 

Plutonium 
242 



38 



Ag), ferrum (iron — Fe), cuprum (copper — Cu), 
slannum (tin — Sn), plumbum (lead — Pb), hydrar- 
gyrum (mercury — Hg). 

By 1800, thirty-four elements had been discovered. 
Within the next ten years, thirteen more had been 
added and had been given made-up Latin names — 
among them natrium (sodium — Na), kalium (potas- 
sium — K), and aluminium (aluminum — Al). By 
the beginning of the twentieth century, eighty-four 
elements were known. 

Today the number has reached 102 — the last ten 
man-made, produced by splitting the atoms of other 
elements. Within a short time, Element 103 will 
probably be discovered. 

In this table you will find listed the 102 elements 
that are known today. Each element is described by 
its chemical symbol, its atomic number, its full name, 
and its atomic weight. 



magnesium 





MANY SCIENTISTS HAD 
NOTICED THAT IF YOU LINE 
UP THE ELEMENTS ACCORD- 
ING TO ATOMIC WEIGHTS, 
CERTAIN CHEMICAL TRAITS 
OCCUR PERIODICALLY. THE 
RUSSIAN SCIENTIST, DMI- 
TRI MENDELEEFF, ON THIS 
BASIS DISCOVERED THE PE- 
RIODIC LAW AND DEVEL- 
OPED THE PERIODIC TABLE. 



dSSWMBttW 




40" 



riOUTA t4\J* CCCP 

_^_^_ IOS7r m 




A YOUNG ENGLISH SCIEN- 
TIST, HENRY MOSELEY, PER- 
FECTED THE PERIODIC TA- 
BLE. HE DISCOVERED THE 
LAW OF ATOMIC NUMBERS 
AND ARRANGED THE ELE- 
MENTS ACCORDING TO 
THE ELECTRIC CHARGE 
FOUND IN THE NUCLEUS. 



chlorine 



THE NUMBER OF PROTONS IN AN ATOM IS ITS 
ATOMIC NUMBER. AN ATOM ALWAYS HAS THE 
SAME NUMBER OF PROTONS AND ELECTRONS. 
HYDROGEN IS THE SIMPLEST OF ALL ATOMS. 



VIII 



I B 



II B 



III B 



IV B 



V B 



VI B 



VII B 



Boron 
10.82 



Al 13 

Aluminum 
26.98 



C 6 

Carbon 
12.011 



Si 14 

Silicon 
28.09 



N 7 

Nitrogen 

14.008 



P 15 

Phosphorus 
30.975 



O 8 

Oxygen 
16 



16 



Sulfur 
32.066 



F 9 

Fluorine 
19 



CI 17 

Chlorine 
35.457 



Co 27 

Cobalt 
58.94 



Rh 45 

Rhodium 
102.91 



lr 77 

Iridium 
192.2 



Ni 28 

Nickel 
58.71 



Pel 46 

Palladium 

106.4 



Pt 78 

Platinum 
195.09 



Cu 29 

Copper 
63.54 



Ag 47 

Silver 
107.88 



Au 79 

Gold 
197 



Zn 30 

Zinc 
65.38 



Go 

Gallium 
69.72 



31 



Ge 32 

Germanium 
72.6 



As 33 

Arsenic 
74.91 



Se 34 

Selenium 
78.96 



Br 35 

Bromine 
79.916 



Cd 48 

Cadmium 

112.41 



In 49 

Indium 
114.82 



Sn 50 

Tin 
118.7 



Sb 51 

Antimony 
121.76 



Te 52 

Tellurium 
127.61 



I 53 

Iodine 
126.91 



Hg 80 

Mercury 
200.61 



Tl 81 

Thallium 
204.39 



Pb 82 

Lead 
207.21 



Bi 83 

Bismuth 
209 



Po 84 

Polonium 
210 



At 85 

Astatine 
210 



HEAVY 
METALS 



METAL- 
LOIDS 



NON- 
METALS 



RARE 

EARTH 

METALS 



UNSTABLE 
ELEMENTS 



Eu 63 

Europium 
152 



Am 95 

Americium 
243 



Gd 64 

Gadolinium 
157.26 



Tb 65 

Terbium 
158.93 



Cm 96 

Curium 
247 



Bk 97 

Berkelium 
249 



Dy 66 

Dysprosium 
162.51 



Ho 67 

Holmium 
164.94 



Cf 98 

Californium 
249 



E 99 

Einsteinium 
254 



Er 68 

Erbium 
167.27 



Tm 69 

Thulium 
168.94 



Yb 70 

Ytterbium 
173.04 



Lu 71 

Lutetium 
174.99 



Fm 100 

Fermium 
255 



Mv 101 

Mendelevium 
256 



No 102 

Nobelium 
251 



? 103 



39 




I lie JViysteries of 



ions 



SVANTE ARRHENIUS DEVELOPED THEORY TO EX- 
PLAIN HOW SOLUTIONS CONDUCT ELECTRICITY. 




IN HIS EARLY EXPERIMENTS, SVANTE 
ARRHENIUS USED A SIMPLE SET-UP. 
YOU CAN EASILY REPEAT SOME OF HIS 
EXPERIMENTS IN YOUR OWN LAB, 
USING FLASHLIGHT BATTERIES. 




From the earliest days, scientists experimenting 
with chemistry have worked with solutions. The 
liquid they used for making a solution (usually 
water) they called the "solvent." The chemical dis- 
solved was the "'solute." 

When chemists began to use electricity as one of 
their tools, they discovered that different solutions 
behaved in different ways. The solution in water of 
a great number of chemicals — sugar among them 
— did not let electricity pass through. They were 
"non-conductors." Some chemicals, on the other 
hand, conducted electricity very easily. They were 
good conductors — "electrolytes." 

In 1874 a Swedish scientist named Svante Arrhe- 
nius developed a theory to help explain the mysteri- 
ous behavior of solutions. He was only 25 years 
old at the time. 

His idea was that when a chemical that conducts 
electricity is dissolved in water, each molecule is 
broken up — "dissociated" — into electrically char- 
ged atoms or groups of atoms. These atoms or groups 
of atoms Arrhenius called "ions" from a Greek word 
that means "to wander." His new theory came 
to be called "Arrhenius' theory of ionization." 

When table salt (sodium chloride, NaCl), for in- 
stance, is dissolved in water, it ionizes into positively 
charged sodium ions (Na T ) and negatively charged 
chlorine ions (Cl — ). These ions "wander" about in 
all directions until an electric current is applied to the 
solution. When that happens, the negative ions rush 
to the positive pole, the positive ions to the negative 
pole. It is the ions that conduct the current through 
the solution. 

The reason that non-conductors do not conduct 
electricity is that they do not dissociate into ions. 

Arrhenius' theory of ionization helped explain a 
great number of things that have puzzled chemists. 
His theory has been modified somewhat, over the 
years but in most respects holds true today. 

CONDUCTIVITY OF SOLUTIONS 

SET UP THE SAME APPARATUS 
AS ON PAGE 25. ADD FLASH- 
LIGHT BULB TO END OF ONE 
WIRE. TRY DIFFERENT SOLU- 
TIONS IN GLASS. SOME CON- 
DUCT ELECTRICITY AND BULB 
LIGHTS UP. OTHERS DO NOT 
AND THE BULB DOES NOT 
LIGHT UP. 



40 



SATURATED SOLUTIONS 

A SATURATED SOLUTION IS ONE 
IN WHICH NO MORE OF THE 
CHEMICAL WILL GO IN SOLU- 
TION AT THAT PARTICULAR TEM- 
PERATURE. 

1 POUR 20 ml WATER OF ROOM 
TEMPERATURE INTO A CUSTARD 
CUP. ADD 6 g SALTPETER (POTAS- 
SIUM NITRATE). STIR. ALL THE SALT- 
PETER DISSOLVES. 

2 ADD 3 g MORE SALTPETER. 
STIR. SOME OF THE ADDED SALT- 
PETER DOES NOT DISSOLVE. CLEAR 
LIQUID IS SATURATED AT ROOM 
TEMPERATURE. (AT 20°C, 6.3 g 
KNO, MAKES SATURATED SOLU- 
TION IN 20 ml WATER.) 

3 PLACE CUSTARD CUP OVER ALCOHOL BURNER. ADD 10 g MORE SALT- 
PETER. SOON ALL SALTPETER IS DISSOLVED. AT HIGHER TEMPERATURES 
IT TAKES MORE SOLUTE TO MAKE A SATURATED SOLUTION. (AT BOILING, 
20 ml HjO DISSOLVES 49 g SALTPETER.) 

4 TAKE SOLUTION OFF FIRE. AS IT COOLS, MUCH OF THE SALTPETER 
COMES OUT AS CRYSTALS BY SLOW CRYSTALLIZATION. LIQUID IS AGAIN 
A SOLUTION SATURATED AT ROOM TEMPERATURE. 





Na*S*O s -5H a O 



BEHAVIOR OF SOLUTIONS 





SOLUTION HAS LOWER 
FREEZING POINT THAN 
THE SOLVENT USED. 

IN TRAY WITH INDIVIDUAL 
ICE CUBE CUPS, POUR WATER 
INTO EACH CUP. IN ONE, DIS- 
SOLVE 1 PINCH OF SALT, IN 
NEXT 2 PINCHES, AND SO ON. 
LEAVE ONE WITHOUT SALT. 
PLACE IN FREEZING COMPART- 
MENT. CUPS LEAST SALTED 
FREEZE FIRST. 
SOLUTION HAS HIGHER BOILING 
POINT THAN THE SOLVENT USED. 
WITH CANDY THERMOMETER, 
DETERMINE AT WHAT POINT 
WATER BOILS. ADD 1 PINCH 
OF SALT. WHAT IS BOILING 
POINT NOW? ADD MORE 
SALT. READ AGAIN. 



CRYSTALLIZATION 

YOU CAN FOLLOW 
CRYSTALLIZATION OF 
MgSO«. IN TEST TUBE, 
HEAT MIXTURE OF 
5 ml WATER AND 1 
TEASPOON EPSOM 
SALT UNTIL SALT DIS- 
SOLVES. POUR HOT 
SOLUTION OVER 
PANE OF GLASS 
CLEANED WITH DE- 
TERGENT. CRYSTALS 
MAKE NEEDLE-LIKE 
NETWORK. 




MANY CHEMICALS 
FORM CRYSTALS OF 
DISTINCT SHAPES. 

FeS0 4 -7H J 




MAKING SOLUTIONS 

MAKE 50 ml GRADUATE FIRST: MEASURE 50 ml WATER 
INTO A NARROW JAR, USING 10 ml TEST TUBE GRADU- 
ATE SHOWN ON PAGE 1 5. MAKE A MARK AT 50 ml LEVEL. 

10% (10 PER CENT) SOLUTION: MEASURE 40 ml WA- 
TER INTO A CUSTARD CUP. ADD 5 g OF THE CHEMICAL. 
STIR. (TO MAKE IT DISSOLVE QUICKER, YOU MAY WANT 
TO HEAT THE WATER SLIGHTLY.) POUR SOLUTION INTO 
50 ml GRADUATE. ADD WATER TO THE 50 ml MARK. 

2% SOLUTION: MEASURE 40 ml WATER INTO CUSTARD 
CUP. ADD 1 g OF THE CHEMICAL. STIR TO DISSOLVE. 
POUR INTO 50 ml GRADUATE. ADD WATER TO 50 ml. 



41 



HOW DO YOU KNOW AN ACID? 



ACIDS TASTE SOUR. 





ADD 5 ml HYDRO- 
CHLORIC ACID TO 15 
ml V/ATER. DROP 5 
DROPS OF MIXTURE IN 
GLASS OF WATER. DIP 
FINGER IN THIS HIGH- 
LY DILUTED ACID. 
TASTE DROP ON FIN- 
GER TIP. 



2. ACIDS ACT WITH 
INDICATORS. 




PLACE DROP OF DILUTED HYDRO- 
CHLORIC ACID ON STRIP OF BLUE 
LITMUS PAPER. THE COLOR CHANGES 
TO RED. 



(ty ACIDS ACT WITH 
METALS. 





PLACE A STRIP OF ZINC IN 
A TEST TUBE. POUR A FEW 
ml HYDROCHLORIC ACID 
ON IT. ZINC DISSOLVES, 
SETTING THE HYDROGEN 
OF ACID FREE. 



4. ACIDS NEUTRALIZE 
BASES. 




COLOR 2 ml LYE SOLUTION 

With a drop of phenol- 
phthalein solution. 

POUR INTO 5 ml HYDROCHLORIC 
ACID. THE PINK COLOR DISAPPEARS. 



orKiiij 

ACIDS have many traits in common. They taste 
sour. They change the color of certain plant sub- 
stances — which are called '"indicators." They con- 
tain hydrogen (II) that can be replaced by a metal. 
They neutralize bases. 

But what is an acid? Earlier, the "acidic" traits 
were used to define an acid. But with the modern 
understanding of the atom, a different definition is 
used. You will remember that the nucleus of an atom 
contains positively charged protons. Acids in solu- 
tion liberate protons as ions (H + ). And so we say 
that an acid is a substance that will give up — or 
"donate" — protons to another substance. Acids are 
"proton donors." The foremost acids used in industry 
are sulfuric acid (H 5 S0 4 ), nitric acid (HNO s ), and 
hydrochloric acid (HC1). 

The first two — sulfuric acid and nitric acid — 
should NEVER be used in the home lab. They are 
much too DANGEROUS. They destroy the skin and 
might blind you if you got them in the eyes. (Wher- 
ever a chemical experiment would ordinarily call for 
sulfuric acid, this book uses sodium acid sulfate — 
NaHSOj, sodium bisulfate. "Sani-Flush": wherever 
(CONTINUED ON PAGE 44) 



HOME-MADE INDICATORS 





CUT UP OR GRATE A 
RED CABBAGE LEAF. 
DROP IN HOT WATER. 
STEEP FOR i/ 2 HOUR. 
POUR OFF LIQUID. USE 
AS INDICATOR. 



elderberries 



cherries 




violet 



bl 



ueberries^V 



MANY FLOWERS AND FRUITS CONTAIN COLORING 
MATTER WHICH YOU CAN EXTRACT WITH HOT V/ATER 
AND USE AS AN INDICATOR FOR ACIDS AND BASES. 



42 



z. 



nig Witli 



ases 



BASES taste brackish. They change the color of 
"indicators." They contain a combination of oxygen 
and hydrogen atoms called "hydroxyl" (OH). They 
neutralize acids. 

But what is a base? When a base is dissolved in 
water it liberates negatively charged hydroxyl ions 
(0H — ). When a base is neutralized, these ions take 
on — or "accept" — positively charged protons from 
another substance. A base is a substance that will 
accept and combine with protons from another sub- 
stance. Bases are "proton acceptors." The most im- 
portant bases are sodium hydroxide ("lye," NaOH). 
ammonium hydroxide ("ammonia." XII s OH). and 
calcium hydroxide ("slaked lime," Ca(OH) 2 ). 

The first of these — sodium hydroxide — is used 
in many households to clean sluggish drains and to 
keep sinks from stopping up ("Drano"). USE IT 
WITH GBEAT CARE in your experiments. Do 
not touch lye flakes with your fingers and do not 
gel the solution on your skin — it dissolves the natu- 
ral oil. It is particularly dangerous to get lye in 
your eyes. If you get lye on you. dilute it quickly 
with LOTS OF WATER. 

(CONTINUED ON PAGE 45) 



s 



LABORATORY INDICATORS 




LITMUS PAPER IS MOST 
COMMONLY USED INDICA- 
TOR. AN ACID TURNS BLUE 
LITMUS RED. BASES TURN 
RED LITMUS BLUE. 





pHYDRION PAPER 
IS MORE EXACT 
INDICATOR FOR 
ACIDS AND BASES. 



WHITE PHENOLPHTHALEIN 
TURNS PINK WITH BASES. 
GET SMALL AMOUNT FROM 
DRUG STORE. DISSOLVE A 
PINCH (0.05 g) IN 50 ml 
DENATURED ALCOHOL. 




HOW DO YOU KNOW A BASE? 



I. BASES TASTE BRACKISH. 





DISSOLVE 5 g (1 TEA- 
SPOON) LYE IN 50 ml 
WATER. DROP 5 
DROPS OF SOLUTION 
IN GLASS OF WATER. 
DIP FINGER IN THIS 
HIGHLY DILUTED 
BASE. TASTE DROP 
ON FINGER TIP. 



2.! BASES ACT WITH 
INDICATORS. 




PLACE DROP OF LYE SOLUTION ON 
RED LITMUS PAPER. THE COLOR IN- 
STANTLY CHANGES TO BLUE. 



3. BASES ACT WITH 
FAT. 



ADD TINY LUMP OF FAT 
TO 5 ml LYE SOLUTION. 
HEAT GENTLY. FAT DIS- 
SOLVES TO FORM SOAP. 




4. BASES NEUTRALIZE 
ACIDS. 





1 . TO 2 ml DILUTED HCI ADD 
A SINGLE DROP OF PHENOL- 
PHTHALEIN SOLUTION. 

2 POUR INTO 5 ml LYE SOLUTION. 
THE MIXTURE TURNS A BRILLIANT PINK. 



43 



HOUSEHOLD ITEMS CONTAINING ACIDS 




ACID FROM 

NON-METALLIC 

OXIDE 




IGNITE A SULFUR CANDLE (OR A 
TINY HEAP OF FLOWERS OF SUL- 
FUR) ON A PIECE OF TIN. HOLD 
MOISTENED BLUE LITMUS PAPER 
OVER FLAME. SULFUROUS ACID 
FORMED TURNS IT RED. 



ACID FROM A SALT 



Acids — Oonfanmeci 

nitric acid would be called for, this book produces 
it in a mixture of a nitrate, KN0 3 , and sodium bi- 
sulfate.) 

Hydrochloric acid is used in many households un- 
der the name of "muriatic acid." Whenever you use 
hydrochloric acid in an experiment-. USE IT WITH 
GREAT CARE. If any of it gets on you, dilute it 
quickly with LOTS OF WATER. Or neutralize it 
with bicarbonate of soda (but not if in the eyes). 





pH SYSTEM IS A WAY OF DESCRIBING THE RELATIVE 
ACIDITY OR ALKALINITY OF A SOLUTION. PURE WATER 



SET UP APPARATUS AS SHOWN. 
INTO TEST TUBE A DROP MIXTURE 
OF y, TEASPOON TABLE SALT AND 
'/ 2 TEASPOON SODIUM BISULFATE. 
HEAT. HYDROGEN CHLORIDE PRO- 
DUCED TURNS MOISTENED BLUE LIT- 
MUS RED. ADD 2 ml WATER TO TEST 
TUBE B. SHAKE. RESULT IS WEAK 
HYDROCHLORIC ACID. 

IS NEUTRAL WITH pH7. THE LOWER THE NUMBER BE- 
LOW 7, THE MORE ACID THE SOLUTION. THE HIGHER 



HYDROCHLORIC ACID LEMONS 
SULFURIC ACID 



UhT] l h j 



LI 



SAUERKRAUT 



TOMATOES 



ACETIC ACID 



^ 



I 



SALIVA 



STOMACH CONTENTS 



BORIC ACID 



IpH J J I pH 6\ 



MILK 



LITMUS 



RED CABBAGE 



PHENOLPHTHALEIN 



j pHYDRION 



44 




HOUSEHOLD ITEMS CONTAINING BASES 




LYE 




BASE FROM 
METALLIC OXIDE 



PLACE A LUMP OF LIME (QUICKLIME, 
CALCIUM OXIDE) IN A CUSTARD CUP. 
ADD AS MUCH LUKEWARM WATER AS 
IT WILL ABSORB. LIME HEATS UP, GIVES 
OFF STEAM, CRUMBLES INTO POWDER 
OF SLAKED LIME (CALCIUM HYDROXIDE). 



scouring 

powder 



ases — v^oniiniuie 



You can also neutralize it with vinegar (but not if 
in the eyes). 

Ammonia is a common household cleaning liquid. 
Ammonia should also be handled with care and 
should be washed off quickly if you get it on you. 
Also watch your nose when you work with ammonia. 
It has a very strong smell. 

Calcium hydroxide is a white powder. You will 
use it in a great number of experiments. 



BASE FROM A SALT 



IN A CUSTARD CUP, DISSOLVE 1 
TEASPOON SAL SODA (WASHING 
SODA, SODIUM CARBONATE) IN 
50 ml WATER. HEAT SLIGHTLY. ADD 
SLAKED LIME MIXED WITH WATER. 
STIR. CHEMICAL REACTION PRO- 
DUCES SODIUM HYDROXIDE AND 
CALCIUM CARBONATE. FILTER. 
CLEAR LIQUID CONTAINS THE SO- 
DIUM HYDROXIDE (LYE). THE CAL- 
CIUM CARBONATE IS HELD BACK 
BY THE FILTER. 



THE NUMBER ABOVE 7, THE MORE ALKALINE THE SO- CHANGES COLOR, YOU CAN DETERMINE THE ACIDITY 

LUTION. WHEN YOU KNOW AT WHAT pH AN INDICATOR OR ALKALINITY OF THE SOLUTION YOU ARE TESTING. 




r- WATER 



$ 



-URINE 



-SEA WATER 



r 



BORAX 



BICARBONATE OF SODA 



MILK OF MAGNESIA 
AMMONIA 



LYE 



LIME WATER 



LITMUS 



RED CABBAGE 



PHENOLPHTHALEIN 



pHYDRION 



45 



>al£s — CJiemicals of .Many Us 



NEUTRALIZATION IS USED 
EXTENSIVELY IN CHEMICAL 
ANALYSIS IN A TECHNIQUE 
CALLED TITRATION. 





TO DETERMINE THE UNKNOWN STRENGTH 
OF A BASE, THE CHEMIST DROPS INTO IT 
FROM A LONG TUBE — A BURETTE — AS MUCH 
ACID OF KNOWN STRENGTH AS IS NECES- 
SARY TO NEUTRALIZE IT. BY CHECKING ACID 
USED HE FIGURES STRENGTH OF BASE. 

1 FOR A TRY AT TITRATION, MIX A 
FEW ml OF HOUSEHOLD AMMONIA 
WITH 40 ml WATER. ADD A DROP OF 
PHENOLPHTHALEIN. THIS WILL COLOR 
THE MIXTURE A DEEP PINK. 

2 POUR 10 ml DILUTED HYDROCHLORIC 
ACID INTO MEASURING TUBE. POUR SOME 
OF THIS ACID INTO THE AMMONIA UNTIL 
COLOR HAS ALMOST VANISHED. 

3 PICK UP A FEW ml 
OF THE MEASURED 
-- ACID IN AN EYE DROP- 
PER (PIPETTE). DROP 
ACID SLOWLY INTO 
THE AMMONIA MIX- 
TURE UNTIL COLOR IS 
COMPLETELY GONE. 
RETURN ACID NOT 
USED TO MEASURING 
TUBE. YOU NOW 
KNOW HOW MANY 
ml ACID YOU HAD TO 
USE TO NEUTRALIZE 
THE AMMONIA. 



ses 

What happens when you neutralize an acid with a 
base or a base with an acid? The hydrogen atoms 
(H + ions) of the acid combine with the hydroxy! 
groups (0H — ions) of the base to form water, and 
the metal atoms of the base combine with what re- 
mains of the acid to form a salt. Or simply: 
BASE plus ACID turns into 
WATER plus SALT 

This, for example, is what happens when you neu- 
tralize sodium hydroxide with hydrochloric acid: 

NaOH + IIC1 — HOH + NaCI 
The result is water and sodium chloride — ordinary 
table salt which has given its name to other sub- 
stances of a similar nature. 

Of all the salts used in industry, table salt (NaCI) 
and washing soda (Na 2 C0 3 ) are of greatest impor- 
tance. Numerous other chemicals are produced from 
them. Our way of life would be completely disrupted 
if our country's industry did not have enough of 
these two salts. 

Many other salts are necessary for our well-being. 
You'll probably find at least half a dozen different 
salts used daily in your home — in cooking and 
baking, in gardening, for cleaning. 

In your chemical experiments you'll be working 
with two classes of salts: normal sails (such as NaCI, 
Na»CO„ KI) which contain no free hydrogen or 
hydroxy! ions, and acid salts (such as NaHSO < 
NaHCOi) which contain replaceable hydrogen. 

Some of these salts dissolve easily in water — all 
the nitrates (salts of nitric acid) and most of the 
chlorides (salts of hydrochloric acid). Many salts, 
on the other hand, are insoluble — most of the car- 
bonates (salts of carbonic acid) and most sulfides 
(salts of hydrosulfuric acid). 



HOW 


THE NAMES OF SALTS ARE MADE UP 








FORMULA AND 


FORMULA AND 


THE ACID 






NAME OF ACID 


NAME OF SALT 


SULFURIC ACID 




H a S0 4 


HYDROGEN SULFATE 


Na,S0 4 SODIUM SULFATE 


NITRIC ACID 




HNO, 


HYDROGEN NITRATE 


NoNO, SODIUM NITRATE 


CARBONIC ACID 




H.CO, 


HYDROGEN CARBONATE No.CO, SODIUM CARBONATE 


ACETIC ACID 




HC,H,0 


, HYDROGEN ACETATE 


NaC,H,0, SODIUM ACETATE 


HYDROCHLORIC 


*CID HCI 


HYDROGEN CHLORIDE 


NoCI SODIUM CHLORIDE 


HYDROSULFURIC 


ACID H,S 


HYDROGEN SULFIDE 


No,S SODIUM SULFIDE 


SULFUROUS ACID 




H,SO, 


HYDROGEN SULFITE 


Na,SO, SODIUM SULFITE 


NITROUS ACID 




HNO, 


HYDROGEN NITRITE 


NaNO, SODIUM NITRITE 


CHLOROUS ACID 




HCIO, 


HYDROGEN CHLORITE 


NaCIO, SODIUM CHLORITE 






REMEMBER: -IC ACIDS FORM -ATE SALTS; 


HYDRO- 


-IC 


ACIDS FORM -IDE SALTS; -OUS 


ACIDS FORM -ITE SALTS 



46 



HOUSEHOLD ITEMS CONTAINING SALTS 




DIFFERENT WAYS OF PRODUCING SALTS 



SALT FROM 
METAL AND 
ACID 




SALT FROM METAL 
OXIDE AND ACID 



DROP ZINC STRIPS 
INTO A TEST TUBE. 
POUR IN A COUPLE 
OF ml HYDROCHLORIC 
ACID. THE ZINC DIS- 
PLACES THE HYDRO- 
GEN OF THE ACID TO 
FORM A SALT (ZnCI,) 
WITH THE CHLORINE. 




PLACE 1 TEASPOON CALCIUM 
OXIDE (QUICKLIME) IN A 
GLASS. ADD HYDROCHLORIC 
ACID WHILE STIRRING. THE 
QUICKLIME DISSOLVES IN THE 
ACID, FORMING CALCIUM 
CHLORIDE AND WATER. 




TWO SALTS FROM 
TWO OTHER SALTS 



SALT FROM ANOTHER 
SALT AND ACID 




DROP PIECES OF CHALK, MARBLE, OR OYS- 
TER SHELLS (ALL OF THEM CALCIUM CAR- 
BONATES) IN A FEW ml HYDROCHLORIC 
ACID. RESULT IS CALCIUM CHLORIDE AND 
CARBONIC ACID (WHICH BREAKS UP INTO 
CARBON DIOXIDE AND WATER). 



There are many ways of producing a salt in ad- 
dition to neutralization. 

When you made iron sulfide directly from the two 
elements iron and sulfur, you produced a salt: 
Fe -4- S — FeS 
When you caused zinc metal to react with hydro- 
chloric acid, you made a salt: 

Zn + 2H® — ZuStj + H, 
W hen you made sodium hydroxide, you used a 




DISSOLVE 5 g EP- 
SOM SALTS (MAGNESI- 
UM SULFATE) IN 20 ml. 
WATER. BRING TO BOIL. 

(ST DISSOLVE 5 g SODA 
IN 20 ml WARM WATER. 
POUR INTO HOT EPSOM 
SALT SOLUTION. 

(3) FILTER THE MILKY 
MIXTURE. THE FILTRATE 
CONTAINS SODIUM SUL- 
FATE. MAGNESIUM CAR- 
BONATE IS RETAINED BY 
FILTER. 



base and a salt to form a new base and a new salt: 
Ca(OH). + Najfli— ' 2NaOH + CaCO, 
A salt and an aeid often form another salt and 
another acid: 

CaC0 3 + 2HG1 — 
CaGli + H 2 C0 3 (H 2 -f- C0 2 ) 
Two soluble salts may also form two other salts — 
one of them insoluble: 



N aj CO s + -M 



MgCOi 4- Na 3 SO, 



47 



Iodine — V lolei 



or 



row n 



? 



Iodine is an interesting element to experiment with. 
It is easily driven out of its compounds as beautiful, 
violet fumes that turn into grayish-black, metallic- 
looking crystals on cooling. These crystals can be 
further purified by turning them into vapor again, 
and again cooling them into crystal form. This proc- 
ess is called "sublimation." 

You are probably familiar with the 2% alcoholic 
solution of iodine known as "tincture of iodine." It 
is found in almost every home medicine cabinet and 
is used as a disinfectant for wounds. Iodine has many 
other uses — in photography and in the preparation 
of various medicines and dyes. 

Iodine has the bad habit of staining practically 




A 



I0D/KJE 



II O D I N E 
Element 53. 
At. wl. 126.91. 
Gray-black crys- 
tals of a peculiar 
odor. Sublimes with 
violet color. Com- 
bines directly with 
metals and non- 
meta Is. It has a 
density of 4.9. 



everything with which it comes in contact with a 
brown stain that won't come off in washing. That's 
why it is advisable to have sodium thiosulfate — 
photographer's fixing salt, "lvypo" — around when 
you work with iodine. Hypo in solution forms a 
colorless compound with iodine. 



MAKING IODINE 

tIN A PYREX CUSTARD CUP 
TOGETHER 2 g POTASSIUM 
IODIDE, 2 g MANGANESE DIOX- 
IDE, 4 g SODIUM BISULFATE. HEAT 
MIXTURE GENTLY. SOON VIOLET 
FUMES EMERGE. 



Be careful not to breathe fumes. 




(2 ) DROP HALF A DOZEN ICE CUBES 
INTO A JAR. ADD A LITTLE WATER. 
PLACE JAR AS A LID ON TOP OF 
CUSTARD CUP. THE VIOLET FUMES 
SETTLE ON BOTTOM OF JAR AS 
GRAYISH-BLACK, SHINY IODINE 
CRYSTALS. 




SCRAPE IODINE CRYSTALS OFF BOTTOM OF JAR. 
KEEP THEM IN SMALL, TIGHTLY CLOSED BOTTLE. 



SOLUBILITY OF IODINE 




^J 



TO TEST SOLUBILITY OF 
IODINE, DROP A FEW CRYS- 
TALS IN EACH OF FOUR TEST 
TUBES. ADD SOLVENT AND 
SHAKE TUBE. 



f 




















" 


■■ J 




» t 








1 












t^J 




K—J 




s 




h. A 




fc. ^ 









.? 



hardly any 

iodine 

dissolves 

when put in 

plain water. 



iodine 
dissolves in 
water if you 
add potas- 
sium iodide. 



iodine 
makes violet 
solution in 
carbon tet- 
rachloride. 



iodine 

dissolves 

with brown 

color in 

alcohol. 



48 



IODINE FREED BY CHLORINE 







SET UP APPARATUS AS DESCRIBED ON PAGE 35 WITH THIS 
EXCEPTION: IN BOTTLE B, MAKE SOLUTION OF '/ 2 g PO- 
TASSIUM IODIDE IN 40 ml WATER. AS CHLORINE BUBBLES 
THROUGH THIS SOLUTION IT TURNS BROWN FROM THE 
FREED IODINE. WITH MORE CHLORINE IT CLEARS AGAIN 
WHEN COLORLESS IODIC ACID FORMS. 



IODINE BY OXIDATION 





DISSOLVE A FEW CRYSTALS OF 
POTASSIUM IODIDE AND A FEW 
GRAINS OF SODIUM BISULFATE 
IN 5 ml WATER. ADD HYDROGEN 
PEROXIDE. SHAKE. THE FREE 
IODINE COLORS LIQUID BROWN. 





^^ 



THE CHLORINE IN 
LIQUID BLEACH ALSO 
FREES IODINE. ADD 
A COUPLE OF DROPS 
TO SOLUTION OF A 
FEW POTASSIUM 
IODIDE CRYSTALS IN 
10 ml WATER. 



MAKING 
HYDROGEN IODIDE 





MIX A FEW CRYSTALS (AS 
MUCH AS A PEA) OF PO- 
TASSIUM IODIDE WITH V A 
TEASPOON SODIUM BISUL- 
FATE. PLACE STRIPS OF 
WETTED LITMUS PAPER AT 
THE MOUTH OF TUBE. HEAT 
GENTLY. IODINE IS RE- 
LEASED. ALSO HYDROGEN 
IODIDE— AN ACID THAT 
TURNS BLUE LITMUS RED. 



STARCH TEST 
IODINE 





REMOVING 
IODINE STAIN 



PAINT PAPER WITH IODINE. DISSOLVE A FEW CRYSTALS OF SODIUM 
THIOSULFATE ("HYPO") IN WATER. PAINT WITH THIS SOLUTION OVER 
THE BROWN COLOR. YOU WILL GET WHITE LETTERS AS HYPO FORMS 
COLORLESS COMPOUND WITH IODINE. 



SHAKE UP A PINCH OF STARCH WITH 
COLD WATER IN A TEST TUBE. ADD TO 
HOT WATER. BRING TO A BOIL. COOL. 
POUR DROP OF MIXTURE INTO 10 ml 
WATER. ADD DROP OF IODINE SOLU- 
TION. BRIGHT BLUE COLOR RESULTS. 




49 




MOST OF OUR SUL- 
FUR IS PRODUCED 
BY DRIVING IT OUT 
OF THE GROUND 
IN MELTED FORM BY 
A PROCESS INVENT- 
ED BY HERMAN 
FRASCH. 



SSULFUR 
Element 16. 
Atomic Wt.: 
32.066. Density: 
2.07. Yellow crys- 
tals. Insoluble in 
water. Melts at 
119°C. Boils at 
444°C. Burns in 
air with blue flame. 



olrar and its Oonapounds 

In tiie old days, sulfur was called "brimstone" 
("burning stone" — from an old word, brennen, to 
burn). When it burned with a blue flame and a suf- 
focating smell, people were certain that the devil 
himself was around. 

Until fairly recently, most sulfur came from the 
volcanic Italian island of Sicily. But today, America 
produces most of the world's sulfur. About a hun- 
dred years ago, big deposits were found in Louisiana, 
several hundred feet underground. The problem of 
getting it up was solved in 1894 in a very clever way 
by a young German emigrant, Herman Frasch. He 
piped superheated water underground to melt the 
sulfur, then forced the melted sulfur to the top with 
compressed air. 

Sulfur itself is used for many purposes. By a proc- 
ess called "vulcanization" it turns sticky, gummy 
raw rubber into elastic rubber usable for automobile 
tires and other rubber products. Sulfur also goes 
into such things as matches and gunpowder and 
medical preparations. 

But by far the greatest use of sulfur is in the prep- 
aration of sulfuric acid (H ; S0 4 ). This acid enters 
into the (CONTINUED ON PAGE 52) 



stick sulfur 




sulfur candl 



flowers of sulfur 



SULFUR CAN USUALLY BE BOUGHT IN THREE DIFFERENT 
FORMS: AS STICK SULFUR, SULFUR CANDLES, AND AS A 
POWDER (FLOWERS OF SULFUR). UNDER MICROSCOPE, 
SULFUR POWDER PROVES TO BE RHOMBIC CRYSTALS. 



50 



MELTING SULFUR 




MAKING MONOCLINIC 
CRYSTALS OF SULFUR 



WHEN YOU MELT SULFUR, IT 
GOES THROUGH FOUR STAGES: 

1 . IT FIRST MELTS INTO A WATERY, 
STRAW-COLORED LIQUID. 

2. IT NEXT BECOMES SLOW-FLOW- 
ING, CARAMEL-BROWN. 

3. IT TURNS ALMOST SOLID. 

4. IT BECOMES LIQUID AGAIN AND 
BOILS WITH YELLOW VAPOR. 





HEAT y 2 TEST TUBE FULL OF 
FLOWERS OF SULFUR TILL IT IS 
MELTED WITH LIGHT COLOR. 

POUR MELTED SULFUR INTO A DRY FILTER. AS SOON 

AS CRUST FORMS ON TOP, OPEN UP FILTER PAPER. 

YOU WILL SEE THAT SULFUR HAS FORMED TINY 

NEEDLE-LIKE CRYSTALS. 



1 MAKE A MOLD FROM A NICKEL BY ATTACHING 
A WALL OF SCOTCH TAPE AROUND THE EDGE OF IT. 

2 FILL TEST TUBE '/ 3 FULL OF FLOWERS OF SUL- 
FUR. MELT GENTLY HIGH ABOVE FLAME. POUR INTO 
MOLD. WHEN COOLED YOU HAVE A PERFECT CAST. 



PLASTIC SULFUR 

I MELT l/ 2 TEST 
TUBE POWDERED 
SULFUR. CONTINUE 
HEATING. SOON IT 
NO LONGER FLOWS. 
YOU CAN TURN TUBE 
UPSIDE DOWN WITH- 
OUT ANYTHING 
COMING OUT. 



2 HEAT THE THICK- 
ENED SULFUR FURTHER 
UNTIL IT FLOWS FREE- 
LY AGAIN. THEN POUR 
THE DARK FLUID INTO 
COLD WATER. IT TURNS 
INTO A PLASTIC MASS. 
IN A FEW DAYS THIS 
AGAIN BECOMES YEL- 
LOW SULFUR. 





PRECIPITATED 
SULFUR 

DISSOLVE A FEW CRYS- 
TALS OF HYPO (SODIUM 
THIOSULFATE) IN '/ 2 
TEST TUBE WATER. ADD 
1 DROP OF HYDRO- 
CHLORIC ACID. SOON 
LIQUID TURNS MILKY OF 
EXCEEDINGLY FINE PAR- 
TICLES OF SULFUR. 



51 



SULFUR 
DIOXIDE 
FOR 
BLEACHING 




Be careful not to breathe fumes. 



MAKING 

SULFUROUS 

ACID 




LIGHT SULFUR IN BOTTLE CAP. LOW- 
ER BURNING SULFUR INTO JAR. 
WHEN JAR IS FULL OF FUMES, RE- 
MOVE SULFUR. ADD A FEW ml WA- 
TER. SHAKE. AS S0 2 DISSOLVES IN 
WATER IT FORMS A WEAK ACID— 
SULFUROUS ACID, H,SO,, TEST FOR 
ACID WITH BLUE LITMUS PAPER. 



SULFUR 
DIOXIDE 
FROM 
A SALT 




DISSOLVE Vi TEA- 
SPOON HYPO (SO- 
DIUM THIOSUl- 
FATE) IN 40 ml WA- 
TER. ADD A FEW ml 
HYDROCHLORIC 
ACID. SULFUR DI- 
OXIDE AND PRECIP- 
ITATE OF SULFUR 
RESULT. 



SULFUR 
, DIOXIDE 
!• Compound. 
Molecular wt. 64. 
Colorless gas with 
a choking odor. 
Does not burn nor 
support combus- 
tion. 2.2 weight of 
air. Highly soluble 
in water — 3,937 
vols, in 100 vols, 
at 20° C. 



1 ATTACH WIRE TO SMALL BOTTLE CAP. FILL THE BOTTLE CAP 
HALF FULL OF SULFUR POWDER. LIGHT THE SULFUR. 

2 LOWER BURNING SULFUR INTO A JAR. JAR FILLS WITH FUMES 
OF SULFUR DIOXIDE. AFTER A FEW MOMENTS, COVER THE JAR 
WITH GLASS PLATE TO EXTINGUISH SULFUR. 

ijSJllFT GLASS PLATE. DROP INTO JAR APPLE PEELINGS AND MOIS- 
TENED, BRIGHT-COLORED FLOWER. COVER AGAIN WITH GLASS 
PLATE. IN A SHORT WHILE, COLORS HAVE BLEACHED. 



production — directly or indirectly — of practically 
overy manufactured article we use today. It is used 
in refining gasoline, in making steel and paper, fibers 
and films, plastics and explosives, and thousands of 
other chemicals. 

Sulfur Dioxide — The first step in making sulfuric 
acid from sulfur is to burn the sulfur. 

When burning in the air, each atom of sulfur takes 
on two atoms of oxygen to make one molecule of 
sulfur dioxide gas (S0 3 ). 

By a special, complicated process, sulfur dioxide 
can be forced to take on another oxygen atom and 
form sulfur trioxide (SOj). With water, this makes 
sulfuric acid: 

H,0+ S0 3 — H 2 S0 4 
Hydrogen Sulfide — Many sulfur compounds have 
unpleasant, penetrating smeUs. Some of these com- 
pounds have very complex molecules — just imagine 
a skunk producing a chemical with this formula: 
CH 5 CH 2 CH : CILSH! The smell of rotten eggs, on 
the other hand, comes from the simple compound 
hydrogen sulfide (H 2 S). 

Hydrogen sulfide is used in chemical analysis to 
determine what metals ate found in a certain sub- 
stance. It combines with metals into salts (sulfides) 
that can be distinguished from each other by their 
colors and by the way they react with acids and 
other chemicals. 



52 



NOTE: Perform these experiments out-of-doors or be- 
fore an open window. Be careful not to breathe fumes. 



H,S 



HYDRO- 
GEN SUL- 
FIDE Com- 
pound. Molecular 
wt. 34. Colorless 
gas with odor of 
rollen eggs. Burns 
with a blue flame 
to form SOj. 1.17 
weight of air. Fair- 
ly soluble in water 
—258 vols, in 100 
vols, at 20° C. 



HYDROGEN SULFIDE 

IS AN IMPORTANT LAB- 
TOOL FOR CHEMICAL 
ANALYSIS. 



HYDROGEN SULFIDE 
HAS SMELL OF 
ROTTEN EGGS 





1 DROP INTO A DRY TEST TUBE '/,, 
TEASPOON POWDERED SULFUR AND A 
LUMP OF CANDLE WAX AS LARGE AS 
A PEA. SET UP APPARATUS AS SHOWN. 



MAKE SOLUTION IN TEST TUBE OF 
CHEMICAL YOU WANT TO ANALYZE. 
LEAD GLASS TUBE INTO THE SOLUTION. 



1 HEAT TEST TUBE WITH SULFUR MIX- 
TURE. HYDROGEN SULFIDE BUBBLES 
INTO TEST SOLUTION. IF THIS CON- 
TAINS SALT OF ONE OF THE HEAVY 
METALS, A PRECIPITATE WILL FORM. 

V 



HYDROGEN SULFIDE FROM FeS 

MAKE IRON SULFIDE AS DESCRIBED 
ON PAGE 22. BREAK THE TEST TUBE 
(IN A PAPER BAG). CRUSH THE FeS 
WITH A HAMMER. DROP SMALL PIECES 
IN ANOTHER TEST TUBE. BY ADDING 
HYDROCHLORIC ACID YOU MAKE H,S. 



EXPERIMENTS 
WITH H,S 



2 AFTER A FEW MOMENTS, 
IGNITE H,S AT JET TIP. IT 
BURNS WITH SO, SMELL. 




■ 



1 PUT STOPPER WITH GLASS TUBE 
WITH JET POINT IN TEST TUBE IN 
WHICH YOU MAKE H,S. MOISTEN A 
SILVER COIN. HOLD IT IN H 2 S STREAM- 
ING OUT OF JET. IT TURNS BLACK 
FROM SILVER SULFIDE. 




THE COLOR OF THE SULFIDE FORMED WHEN YOU LEAD H.S 
INTO A SOLUTION CONTAINING A SALT OF A HEAVY METAL 
WILL HELP TELL YOU WHAT METAL IS FOUND IN THE SALT. 



3 HOLD COLD GLASS PLATE IN 
H 2 S FLAME. BECAUSE OF INCOM- 
PLETE COMBUSTION, SULFUR IS 
SET FREE. YOU CAN ACTUALLY 
"DRAW" WITH THE H,S FLAME. 



Na,S 



FeS 




CdS 



CuS 



SbjS, 



ZnS 



O 







MnS 



53 




MAKING CEMENT 



ROLLING GLASS 




SILICON 

Element 14. 

Atomic wf.: 
28.09. Density: 
2.4. Dark-gray me- 
tallic-looking crys- 
tals or brownish 
powder. Burns in 
oxygen. Forms 
about 27% of the 
earth's crust. 



Jilicon — I lie JcJenrieajil 1©m Si ejp On 



Silicon (from the Latin silex, flint) is the second 
most abundant element on earth — after oxygen. 
Whether you are walking on sand or clay, rock or 
cement, almost half of what you're stepping on is 
silicon. 

Silicon is found in nature in combination with 
oxygen (mostly the dioxide, SiO s ) and in different 
silicates (salts of various silicic acids). 

With few exceptions, silicon compounds are in- 
soluble in water. And that is a good thing for all of 
us. The glass of our windows and the glasses from 
which we drink are silicates. So are the glazes on 
our cups and the enamel on our bathtubs. Most 



glass and many glazes are made by fusing together 
sand (Si0 2 ), limestone, and soda. 

The silicates of sodium and potassium dissolve in 
water. A concentrated solution of sodium silicate 
(Na,Si0 3 ) is sold in hardware stores under the name 
of waterglass. It is used as a glue, for fireproofing 
wood and for preserving eggs. 

Within recent years, chemists have developed a 
whole line of new silicon compounds called silicones. 
Some of them are oil-like. Some look like putty 
("Silly Putty"). Still others are rubber-like. Paper 
and cloth can be made water-repellent by being 
treated with suitable silicones. 




SAND — 40% SILICON 



MINERALS AND PRECIOUS STONES 

MANY ARE SILICON OXIDES OR SILICATES. 



.^TX 




flint 



garnet 





rock crystal 






amethyst 



emerald 



agate 



54 



MAKING SILICIC ACID 




; 



IN ONE GLASS, DILUTE 20 ml WATERGLASS WITH 20 ml WATER. 

IN ANOTHER, MIX 10 ml HYDROCHLORIC ACID AND 10 ml WATER. 

3 POUR THE TWO MIXTURES AT ONE TIME INTO A THIRD GLASS. 

4 ) STAND SPOON UPRIGHT IN THE MIXTURE WHICH, ALMOST IMMEDI- 
ATELY, TURNS INTO A JELLY ("GEL") SO STIFF THAT SPOON STANDS BY 
ITSELF AND YOU CAN TURN THE GLASS UPSIDE DOWN. 



MAKING 

SILICON 

DIOXIDE 




PLACE SOME OF THE GEL 
JAR LID. HEAT. THE SILICIC 
GIVES UP WATER (H,0) 
INTO A GRAYISH-WHITE 
SILICON DIOXIDE (SiO,). 



ON A METAL 

ACID (HjSiO,) 

AND TURNS 

POWDER OF 



WEAKNESS OF 
SILICIC ACID 




MAKING 
WATER- 
GLASS 



SILICIC ACID IS SO WEAK THAT CARBONIC 
ACID (H a CO,) DRIVES IT OUT OF WATER- 
GLASS. MAKE THE CO, BY POURING HY- 
DROCHLORIC ACID OVER MARBLE CHIPS. 



MAKING SILICATES 

1 DILUTE 5 ml WATERGLASS 
(Na 2 SiO,) WITH 5 ml WATER. 

2 DISSOLVE SMALL CRYSTAL OF 
COPPER SULFATE IN WATER. 










IN A TEST TUBE, MIX 1 g OF THE SILICON 
DIOXIDE YOU MADE, 2 g LYE (NaOH), AND 5 ml 
WATER. HEAT CAREFULLY, MOVING TUBE. 

2 AFTER FILTERING, YOU WILL HAVE A CLEAR 
SOLUTION OF SODIUM SILICATE (Na,SiO,). 



^^ 



3 ADD A FEW DROPS TO THE 
WATERGLASS TO GET PRECIPI- 
TATE OF COPPER SILICATE. 



GROWING" A SILICON "JUNGLE" 

IN A PINT JAR, PLACE Vi-INCH LAYER 
OF SAND. POUR ON TOP OF THIS A 
MIXTURE OF EQUAL PARTS OF WATER- 
GLASS AND WATER. PLACE IT IN A SPOT 
WHERE IT WILL NOT BE DISTURBED. 
DROP IN CRYSTALS OF VARIOUS SALTS 
YOU MAY HAVE: IRON SULFATE, COP- 
PER SULFATE, ALUM, EPSOM SALT. THE 
CRYSTALS SEND UP "SHOOTS." IN A 
FEW HOURS, YOUR SILICATE "JUNGLE" 
IS FULLY "GROWN." 




DO 




BB O R O N 
Element 5 
Atomic wt.: 
10.82. Density: 
2.54. Yellowish- 
brown crystals or 
greenish-brown 
powder. Burns 
when heated in 
oxygen with 
green flame. 



'(GWILIL 



-Fui 



lire 



oc 



ket~P 



ower 



emen 



t? 



Less than a hundred years ago, a mineral called 
borax, containing the element boron, was carted out 
of Death ^ alley in California by twenty-mule teams 
— about the slowest transportation you can think of. 
Someday, boron may be put in zip-fuels for space 
missiles — the fastest form of transportation imagi- 
nable. Boron has the ability (as does carbon) to 

BORAX BEAD TEST IN CHEMICAL ANALYSIS 




combine with hydrogen in a number of ways. When 
these boranes or boron hydrides burn, they develop a 
tremendous amount of power. 

Boron can be isolated as a hard, brownish-black 
powder. Its carbon compound, boron carbide (B,C), 
is almost as hard as diamond. 

But you are probably more familiar with boron 



MAKE BLOWPIPE BY DRAW- 
ING GLASS TUBING INTO 
JET POINT. 




===% 



IN THE TIP OF 
THE FLAME, THE 
STRONG HEAT 
OXIDIZES METAL 
IN THE TEST SAM- 
PLE. OXIDE COt- 
ORS BEAD. 



CERTAIN METAL OXIDES, FUSED INTO A "BEAD" 
OF MELTED BORAX, PRODUCE DISTINCT COLORS 
BY WHICH THE METALS CAN BE RECOGNIZED. 

TO MAKE TEST, HEAT WIRE LOOP. DIP HOT LOOP IN 
BORAX. HEAT TO FORM BEAD. TOUCH BEAD TO CHEM- 
ICAL TO BE TESTED. OXIDIZE THE CHEMICAL IN VERY 
HOT FLAME GENERATED WITH HELP OF A BLOWPIPE. 
STUDY THE COLOR OF BEAD, HOT AND COOLED. 





hot 


cold 


hot 


cold 


IRON 


O 


O 


MANGANESE O 


O 


COPPER 


o 


o 


COBALT O 


O 


NICKEL 


o 


o 


CHROMIUM O 


O 



through two of its compounds which are found in 
almost even.- household: boric acid (H 3 B0 3 ), used as 
a mild antiseptic, and borax (sodium tetraborate, 
Xa.B.CK'lOII.O), used for cleaning purposes and as 
a water softener. 

Borax has a great number of uses outside the home. 
It is used for soldering, for producing certain kinds 
of soap, and for making other boron compounds. 



The glass industry uses large quantities of borax 
for making boron-aluminum-silicate glass. Yon know 
this kind of glass by its trade name, Pyrex. Kitchen 
utensils and laboratory ware made of Pyrex glass 
have the great advantage over ordinary glass that 
they can be placed directly on the fire and do not 
break so easily when they are subjected to sudden 
heating or cooling. 



MAKING BORIC ACID 

f\ IN A CUSTARD CUP, ADD 
g BORAX TO 15 ml WATER. 
BRING TO BOIL. STIR 
BORAX IS DISSOLVED. 




TESTS FOR 
BORIC ACID 





DROP A FEW CRYSTALS OF BORIC 
ACID IN A CUSTARD CUP. ADD A 
COUPLE ml DENATURED ALCOHOL. 
IGNITE. STIR WITH GLASS ROD. 
BORIC ACID GIVES GREEN EDGES 
TO THE FLAMES. 



YELLOW TURMERIC INDICATOR PA- 
PER TURNS BROWN WITH BORIC 
ACID. YELLOW COLORING MATTER 
IN TABLE MUSTARD IS TURMERIC. 
TO MAKE TEST PAPER, DIP STRIPS 
OF PAPER TOWELING IN MUSTARD. 
WASH MUSTARD OFF. DRY STRIPS. 




{2) ADD 4 ml HY- 
DROCHLORIC ACID 
TO HOT BORAX SO- 
LUTION. STIR. RE- 
MOVE FROM FIRE. 
BORIC ACID CRYS- 
TALLIZES OUT AS 
SOLUTION COOLS. 



3 POUR CONTENTS OF CUS- 
TARD CUP INTO A FILTER. WHEN 
FILTRATE HAS RUN OFF, WASH 
BORIC ACID REMAINING IN FIL- 
TER WITH A SMALL AMOUNT OF 
COLD WATER TO REMOVE NaCI 
ALSO FORMED IN THE PROCESS. 

[ SPREAD OUT FILTER TO LET 
BORIC ACID CRYSTALS DRY. USE 
FOR EXPERIMENTS ONLY. 




MAKING 
BORIC OXIDE 





HEAT BORIC ACID IN AN OLD 
TEASPOON. IT GIVES OFF WA- 
TER AND TURNS INTO SYRUPY 
MASS OF MELTED BORIC OX- 
IDE (B,0,) WHICH YOU CAN 
DRAW INTO THREADS WITH 
GLASS ROD. 



oi 




Wm~ 



"SALARY" COMES FROM SALARIUM 
— THE WAGES PAID IN SALT TO 
ROMAN SOLDIERS. 



closed 
end of 
tube 




CRYSTALLIZING 
SALT BY 
EVAPORATION 



1 DISSOLVE 19 g TABLE 
SALT (NaCI) IN 50 ml HOT 
WATER. BOIL SOLUTION, 
STIRRING WITH GLASS TUBE 
WITH TOP END SEALED (TO 
REDUCE "BUMPING"), UNTIL 
HALF THE WATER HAS BEEN 
EVAPORATED. SALT FORMS 
FINE CRYSTALS. 



TZ-a ^-TT~ 




Jooliiiiii an 



IPota 



ssinm 



■J NATRIUM 




l\ld Element "• 




Atomic wt.: 




22.991. Density: 




0.97. (English: So- 




dium) Silver-white 




metal, can be cut 




with knife. Oxidizes 




in air. Reacts with 




water. Burns with 




yellow flame. 





The salts of sodium and potassium have been used 
for thousands of years in making soap and glass and 
for a great number of other purposes. 

Sodium chloride CXaCl) is the most common sodi- 
um salt — it is the chemical that makes ocean water 
"salty." Plants growing in the ocean take up so 
much of the sodium that people along the seacoasts 
of the world used to burn dried seaweed to secure 
"soda ash" (sodium carbonate, Na,COj). Inland 
plants, on the other hand, pick up potassium from 
the soil. Inland people boiled out wood ashes in large 
pots to get '"potash" (potassium carbonate, K 2 COj). 

In 1807, the British scientist, Humphry Davy, 
succeeded in isolating the metals found in these salts. 
They proved to be wax-soft and silvery. He called 
them sodium (from soda ash) and potassium (from 
potash). These are still their English names. But in 
chemical formulas they are referred to as natrium 
(Na) and kalium (K) — from abbreviations of the 
Arabic names of the ashes: nairun and al qili (alkali). 



MAKING ACID SALT FROM NORMAL SALT 



2 POUR CLEAR LIQUID INTO LARGE PIE PLATE. PLACE 
IN SUNNY WINDOW FOR WATER TO EVAPORATE SLOW- 
LY. THE CRYSTALS FORMED WILL BE MUCH LARGER. 

MAKING NORMAL SALT 
FROM ACID SALT 



SODIUM SULFATE IS PRODUCED 
BY HEATING SODIUM ACID SUL- 
FATE WITH SODIUM CHLORIDE. 





IN A TEST TUBE, HEAT 
A MIXTURE OF 2 g SO- 
DIUM ACID SULFATE (SO- 
DIUM BISULFATE) WITH 
1 g TABLE SALT (NaCI). 
HYDROGEN CHLORIDE 
IS SET FREE AND SODI- 
UM SULFATE IS FORMED: 
NaHSO., + NaCI -* 
HCI + Na 2 SO« 



THE ACID CARBONATE (NaHCO,) IS MADE 
BY LEADING C0 2 TO NORMAL CARBONATE 
(Na 2 CO,). 

1 MAKE SATURATED SOLUTION BY SHAK- 
ING 3 TEASPOONS V/ASHING SODA IN 30 
ml COOL, BUT NOT COLD, WATER. FILTER IT. 

2 SET UP APPARATUS FOR MAKING C0 2 AS 
SHOWN ON PAGE 31 . LEAD CO, INTO SODA 
SOLUTION FOR 1 MINUTES. THEN SET ASIDE. 
SHORTLY NaHCO, CRYSTALS APPEAR. 



58 




KK A I. I U M 
Element 19. 
Atomic wt.: 
39.100. Density: 
0.87. (English: Po- 
tassium) Silver- 
white metal, so soft 
it can be cut with 
knife. Oxidizes in 
air. Reacts with wa- 
ter. Burns with vio- 
let flame. 



PIONEER WOMEN MADE POTASH 
FROM WOOD ASHES. 



NITRATE TO 
NITRITE 



T7TJ 



HEAT Vi TEASPOON 
SALTPETER AT BOT- 
TOM OF A TEST TUBE 
UNTIL IT MELTS. DROP 
INTO THE TUBE A 
PEA-SIZE LUMP OF 
SULFUR. IT BURNS 
WITH BRILLIANT BLUE 
FLAME. DO SAME 
EXPERIMENT WITH 
HEAD OF MATCH, 
CHARCOAL BIT. 



WHEN YOU HEAT PO- 
TASSIUM NITRATE, IT 
GIVES UP OXYGEN 
AND BECOMES PO- 
TASSIUM NITRITE: 
2KNO, -» 
2KNO, + O, 




.Kl 





MAKING 
POTASH 

(53 STIR UP SEVERAL TEA- 
SPOONS OF FRESH WOOD 
ASHES WITH WARM WATER. 
SKIM OFF WOOD REMAINS. 

§ FILTER THE MIXTURE OF 
IES AND WATER. COLLECT 
FILTRATE IN A CUSTARD CUP. 
EVAPORATE MOST OF WATER. 
THEN COOL TO PERMIT K,CO, 
TO CRYSTALLIZE OUT. 




FLAME COLOR TEST FOR SODIUM AND POTASSIUM 



THE COMPOUNDS OF CERTAIN METALS GIVE 
DISTINCT COLORS TO A FLAME. DIP Nl- 
CHROME WIRE IN HCI TO CLEAN IT. HEAT IT. 
THEN DIP LOOP IN COMPOUND AND HOLD 
IN FLAME. 





SODIUM COMPOUNDS GIVE 
THE FLAME A BRIGHT YELLOW- 
RED COLOR. POTASSIUM COM- 
POUNDS GIVE VIOLET FLAME. 



TO SEE VIOLET COLOR OF PO- 
TASSIUM IN MIXTURE WITH 
Na, USE BLUE GLASS TO 
SCREEN OUT YELLOW OF Na. 



59 




"^r^^ 



- v> v . ki 

i if 



A_ CALCIUM 
lj/j Element 20 
Atomic wt.: 
40.08. Density: 
1.54. Silver-while 
metal with bright 
luster. Reacts with 
moist air and water 
to form hydroxide. 
When heated burns 
with brilliant light. 




c. 



. — for Buil 



"THE WHITE CLIFFS OF DOVER" CONSIST OF ALMOST 
PURE CALCIUM CARBONATE IN THE FORM OF CHALK. 




STALACTITES AND STALAGMITES ARE 
UNDERGROUND DEPOSITS OF CaCO,. 



aicuim.- 

Stand up straight. You can do it because your 
bones contain calcium. Tell a mason to put up a 
brick house. He can do it with mortar containing 
calcium. Tell a master builder to build a monument. 
He will make it from marble — calcium again. Tell 
a hen to "go lay an egg." She can do it if she gets 
enough calcium in her feed to make the shell. 

Calcium carbonate (CaC0 3 ) is the starting point 
for most calcium compounds — and for other chemi- 
cals as well. It is found in nature in cliffs and moun- 
tain ranges in the form of chalk and limestone and 
marble. And it makes up the shells of clams and mus- 
sels and billions of tiny sea creatures. 

Calcium carbonate is almost insoluble in water. 
But if the water contains carbon dioxide, some goes 
in solution as calcium bicarbonate (Ca(HC0 3 ) 2 ). 
This explains the formations in our famous limestone 
caves. Rainwater containing carbon dioxide seeped 
through the ground and dissolved a small amount 
of limestone. In falling from the cave ceiling and 
drying, the drops gave up H 2 and C0 2 and left 
CaC0 3 behind. The minute deposits of falling drops 
during thousands of years created the stalactites 
hanging from the roof of the caves and the stalag- 
mites rising from the floor. 

A widespread mineral called gypsum is the sul- 
fate of calcium. Tn this, each molecule of sulfate has 
two molecules of water attached to it (CaSO,-2H 2 0). 
Vl hen gypsum is heated, it loses three quarters of its 
water and becomes plaster of Paris (2CaSO,-H 2 0). 
When you mix plaster of Paris and water, it again 
takes on the full amount of ILO and hardens into 
a hydrate similar to the original gypsum. 

The name of calcium was given to the metal hidden 
in limestone by its discoverer, Humphry Davy. It 
comes from calx, the old Latin name for lime. 




WHEN LIMESTONE IS HEATED IN KILNS, 
IT LOSES CARBON DIOXIDE AND TURNS 
INTO QUICKLIME— CALCIUM OXIDE. 



WHEN WATER IS ADDED TO LUMPS OF QUICKLIME (CaO), 
THEY CRUMBLE INTO A WHITISH POWDER OF SLAKED OR 
HYDRATED LIME (Ca(OH) 2 ). (SEE ALSO PAGE 45.) 



60 




TESTING HARDNESS OF WATER 



MAKE TEST SOLU- 
TION BY DISSOLVING 

1 g SOAP FLAKES IN 20 
ml DENATURED ALCO- 
HOL. FILTER. 

2 FILL A SLENDER JAR 
HALF FULL OF WATER 
TO BE TESTED. ADD 10 
DROPS OF SOAP SOLU- 
TION. CLOSE MOUTH 
OF JAR. SHAKE VIGOR- 
OUSLY. CHECK AMOUNT 
OF FOAM. 






^ 

& 




SOFT TAP 

WATER GIVES 

FAIR AMOUNT 

OF FOAM. 



HARD TAP 

WATER MAKES 

VERY LITTLE 

FOAM. 



HARD WATER 

SOFTENED WITH 

WASHING 

SODA MAKES 

FOAM. 



DISTILLED 

WATER MAKES 

LARGE 

AMOUNT 

OF FOAM. 




MAKING "HARD" WATER 

(f)SET UP GAS GENERATOR AS SHOWN ON PAGE 
3T: BOTTLE A CONTAINS HYDROCHLORIC ACID. IN 
BOTTLE B, PLACE MARBLE CHIPS ON TOP OF PEBBLES. 
POUR ACID ON MARBLE CHIPS TO MAKE CO,. 

LEAD THE CARBON DIOXIDE INTO LIME WATER. 
RNS MILKY THROUGH FORMATION OF CaCO,. 

(3) CONTINUE LEADING CO, INTO MILKY SOLUTION. 
MTLKINESS DISAPPEARS. INSOLUBLE CaCO, HAS BEEN 
TURNED INTO SOLUBLE Ca(HCO,),. THIS IS THE SUB- 
STANCE THAT MAKES MOST HARD WATER "HARD." 



water to be 
distilled is 
in this can 



ITTU 




ice cubes 

in water 

for cooling - 

can upside 
down — bottom - 
removed 

rubber stopper 
with glass tube 



distilled 
water here 









PRECIPITATED 

CALCIUM 

CARBONATE 



1 WHEN MARBLE CHIPS 
HAVE DISSOLVED IN ACID IN 
BOTTLE B IN EXPERIMENT 
ABOVE, POUR SOLUTION INTO 
CUSTARD CUP. HEAT. 

2 WHEN HOT, ADD SOLU- 
TION OF 2 TEASPOONS 
WASHING SODA IN 50 ml 
WATER. YOU GET A HEAVY 
WHITE PRECIPITATE OF CAL- 
CIUM CARBONATE. 



IN THE SCIENTIFIC LABORATORY, ALL IMPURITIES (CAL- 
CIUM CARBONATE AND SULFATE, AND OTHERS) MUST 
BE REMOVED FROM WATER TO BE USED AS SOLVENT. 
THIS IS DONE BY EVAPORATING THE WATER AND 
CONDENSING THE STEAM. YOU CAN MAKE A DIS- 
TILLATION APPARATUS FROM TWO PINT-SIZE CANS. 



CASTING WITH PLASTER OF PARIS 

PLASTER OF PARIS (2CaS0 4 -H,0) IS USED 
IN POLICE WORK FOR MAKING CASTS OF 
TRACKS. MIX PLASTER WITH WATER UNTIL 
IT HAS CONSISTENCY OF MEDIUM CREAM. 
POUR IN TRACK. LEAVE TO SET ONE HOUR. 






ompare 1 w© 



Metals 



HOLD 2-INCH PIECE 
OF MAGNESIUM RIB- 
BON WITH A PAIR 
OF PLIERS. IGNITE IT. 
IT BURNS WITH A 
BRILLIANT, WHITE 
FLAME. MIX ASHES 
(MgO) WITH WATER. 
TEST MIXTURE WITH 
RED LITMUS PAPER. 



,:J* 




CUT SLIVER OF ZINC. 
HOLD IT IN FLAME. IT 
BURNS WITH BLUISH- 
GREEN FLAME TO ZINC 
OXIDE. ZnO IS YELLOW 
WHEN HOT, WHITE 
WHEN COOL. 



Take a look at the periodic table of elements on 
pages 38-39. In column IIA you find the metal mag- 
nesium, in column IIB the metal zinc. The fact that 
the two families in which they are found both have 
the Roman numeral II would indicate that they are 
related. But the fact that they are in separate "'sub- 
groups" would suggest that they differ in certain re- 
spects. That is exactly the case. 

In their compounds they are very much alike. One 
atom combines with one atom of oxygen to form the 
oxide (MgO and ZnO), and one atom replaces two 
atoms of hydrogen in forming a salt (MgClj and 
ZnCK, for instance). But in some of their reactions 
they do not behave alike — as you will learn. 

Before World War II, magnesium had little use 
— mainly in flash photography because it burns with 
a blinding, white light. But the metal became im- 
portant when lightweight planes were needed — 
melted together with other metals it forms an "alloy" 




REPLACEMENT OF COPPER 



1 



CuSCt 




Q 



Rj~J 




m 




1 BOTH METALS REACT WITH WEAK ACIDS, EVEN WITH 
VINEGAR— Mg WITH COLD VINEGAR, Zn WITH HOT. 

2. POUR SOLUTION OF 1 g SODIUM BISULFATE IN 10 
ml WATER ON Mg AND Zn. Mg REACTS FAST, Zn SLOWLY. 
NOW TOUCH ZINC WITH A COPPER WIRE. REACTION 
SPEEDS UP, CAUSED BY ELECTRIC PROCESS. 



..1 i DISSOLVE 4 g COPPER SULFATE IN 40 ml WATER. 
POUR HALF OF THE SOLUTION OVER STRIPS OF MAGNE- 
SIUM, THE OTHER HALF OVER SLIVERS OF ZINC. 

H) COPPER IS FORCED OUT AND Mg AND Zn GO INTO 
SOLUTION. IF ENOUGH METAL IS USED, THE BLUE COLOR 
DISAPPEARS. MgSO„ AND ZnSO« ARE COLORLESS. 



62 




that is light yet very strong. Some magnesium com- 
pounds are used in medicine: milk of magnesia (Mg 
(OH),) and Epsom salt (MgSOWl^O). 

Zinc has been used for ages to coat iron pails and 
pipes to prevent them from rusting — "galvanized 
iron." Zinc is also a part of many alloys (German 
silver and brass) and is important in the making of 
dry-cell batteries. 




MAGNE- 
SIUM 

Element 12. 
Atomic wt.: 24.32. 
Density: 1.75. Sil- 
ver-white metal. 
Ductile, malleable. 
Reacts with boiling 
water. Burns in air 
with very brilliant 
while light. 



7-IINC 

I I! Element 30. 
Atomic wt.: 
65.38. Density: 
7.1. Bluish-white 
metal. Ductile and 
malleable. Distils 
when heated to 
boiling. Can be 
made to burn with 
bluish flame. 




MAKING THE HYDROXIDES 



MAKING THE CARBONATES 



4 





DISSOLVE 2 g EPSOM SALT (MAGNESIUM 
SULFATE, MgS0 4 -7H 2 0) IN 20 ml WATER. 

2 GET FROM HARDWARE STORE SMALL BOT- 
TLE OF "TINNERS' FLUID." THIS IS A STRONG 
SOLUTION OF ZINC CHLORIDE. DILUTE 5ml OF 
FLUID WITH 15 ml WATER. 

'3 MAKE SOLUTION OF 5 g WASHING SODA 
(SODIUM CARBONATE) IN 50 ml WATER. ADD 
SOME OF THIS SOLUTION TO THE OTHER TWO. 
IN BOTH JARS YOU WILL GET A HEAVY WHITE 
PRECIPITATE. IN THE Mg JAR, THIS IS NORMAL 
MAGNESIUM CARBONATE (MgCO,). IN Zn JAR, 
C0 2 IS SET FREE AND BASIC ZINC CARBONATE 
(Zn(OH) 2 ,ZnCO,) RESULTS. 



1 ADD SODIUM HYDROXIDE SOLUTION TO SOLUTION 
OF MAGNESIUM SULFATE. WHITE Mg(OH), FORMS. 

2 ADD SMALL AMOUNT OF NaOH SOLUTION TO DI- 
LUTED TINNERS' FLUID (ZnCI 2 ). Zn(OH) 2 IS FORMED. ADD 
MORE NaOH. PRECIPITATE DISSOLVES WITH FORMATION 
OF SODIUM ZINCATE {Na 2 Zn 2 ). 

3 ADD AMMONIA (AMMONIUM HYDROXIDE) TO MAG- 
NESIUM SULFATE SOLUTION. AGAIN Mg(OH), FORMS. 

4 ADD SMALL AMOUNT OF AMMONIA TO DILUTED TIN- 
NERS' FLUID. Zn(OH) 2 FORMS. ADD MORE. THE Zn(OH) 2 
DISSOLVES, FORMING COMPOUND WITH NH 2 . 



Zn AND Mg 
WITH H 2 S 




1 1 SET UP HYDROGEN SULFIDE APPARATUS SHOWN ON PAGE 53. 

f) LEAD HYDROGEN SULFIDE (H 2 S) INTO DILUTED TINNERS' FLUID 
, nCI 2 ). YOU GET A WHITE PRECIPITATE OF ZnS. 

3 LEAD H 2 S INTO SOLUTION OF EPSOM SALT (MgS0 4 ). HERE 
ALSO YOU GET WHITE PRECIPITATE. BUT NOT OF MAGNESIUM 
SULFIDE. THIS REACTS WITH THE WATER TO MAKE Mg(OH) 2 . 



63 





H. C. 0RSTED OF DENMARK DISCOV- 
ERED ALUMINUM IN 1825. CHARLES 
HALL OF THE UNITED STATES FOUND" 
A CHEAP WAY OF PRODUCING IT 
IN 1886. 



■ I ALUMINUM 
f^| Element 13. 
Atomic wt.: 
26.98. Density: 
2.70. Silver-white 
metal; ductile, mal- 
leable, able to take 
a high polish. Am- 
photeric. Will burn 
in oxygen with 
white flame. 




lindane e 

It is almost impossible to imagine our world with- 
out aluminum. Almost everywhere you look you see 
items made of this silver-white metal — from the 
pots in the kitchen to the airplanes flying overhead. 
Although aluminum is the most abundant metal 
on earth, no one had ever seen it until 1825 when a 
Danish scientist. Hans Christian 0rsted, isolated it 
from aluminum chloride (A1C1 3 ). For a number of 
years aluminum was so expensive that it was con- 
sidered in class •with gold and silver. The solid alumi- 
num cap placed on top of the Washington Monument 
in 1881 was first put on public display so that every- 
one could have a look at such a great rarity. Two 



GROWING ALUM CRYSTALS 



MAKE A SMALL AMOUNT 
OF ALUMINUM POWDER BY 
FILING IT OFF AN OLD ALU- 
MINUM POT. SPRINKLE IN 
FLAME TO MAKE SPARKS 
OF BURNING ALUMINUM. 

DISSOLVING ALUMINUM 








-c^-/ 



CUT ALUMINUM 
FOIL IN SMALL STRIPS. 
DROP THEM IN A LITTLE 
DILUTED HYDROCHLOR- 
IC ACID. HYDROGEN IS 
RELEASED; ALUMINUM 
CHLORIDE IS FORMED. 

.2/ DROP STRIPS OF 
ALUMINUM FOIL IN 10% 
NaOH SOLUTION. HY- 
DROGEN IS FREED AND 
SODIUM ALUMINATE 
(NaAIOJ IS FORMED. 




'1. HEAT WATER UNTIL IT IS SLIGHTLY MORE THAN LUKE- 
WARM. STIR INTO IT POTASSIUM ALUM OR AMMONIUM 
ALUM UNTIL NO MORE DISSOLVES. POUR LIQUID OFF 
UNDISSOLVED ALUM. SET ASIDE TO COOL. 

2 WHEN CRYSTALS HAVE FORMED, PICK OUT LARGEST 
ONES. ADD TO SOLUTION AS MUCH MORE ALUM AS IS 
REPRESENTED BY THE CRYSTALS YOU REMOVED. HEAT 
GENTLY AGAIN UNTIL ALL IS DISSOLVED. COOL. 

3 POUR COOLED SOLUTION INTO NARROW GLASS. TIE 
THREAD TO LARGEST CRYSTAL YOU PICKED. HANG THIS 
IN SOLUTION FROM A PENCIL. PLACE IN QUIET SPOT. 
LET THE CRYSTAL GROW FOR A WEEK OR MORE. 



64 






years later, a 22-year-old American chemist, Charles 
Martin Hall, invented a way of producing aluminum 
cheaply from aluminum oxide (A1 S 0,). Since then 
aluminum has hecome one of the most popular of all 
metals — mostly hecause of its lightness. 

The mineral bauxite (A1H0 : , Al(OH)j) is our main 
source of aluminum. But aluminum is also found in 
nature as oxide and in many complex silicates. Clay, 
for instance, is an aluminum silicate. 



Two things about aluminum will interest you as a 
chemist. One is that aluminum is an "amphoteric" 
element, which means that it can form not only a 
base (A1(0H),), but also an acid (HAIO,). The other 
is that aluminum sulfate (Alj(SO,) 3 ) has the ability 
to combine with potassium sulfate (KjS0 4 ) and am- 
monium sulfate ((NH,) 2 S0 4 ) into beautiful cubic 
crystals of double salts called "alums" — KA1 (S0 4 )j - 
12H,0 and M^AHSOJj-^HA 



MAKING ALUMINUM HYDROXIDE 








£^8 



CLEARING 
WATER 
WITH 
ALUM 




1 DISSOLVE 1 g (Vi TEASPOON) ALUM IN 
10 ml WATER. ADD A LITTLE 10% NaOH 
SOLUTION. YOU GET JELLY-LIKE ALUMINUM 
HYDROXIDE. THIS WILL DISSOLVE IN MORE 
NoOH TO FORM SODIUM ALUMINATE. 

S AMMONIA ADDED TO ALUM SOLUTION 
GIVES ALUMINUM HYDROXIDE. BUT THIS 
DOES NOT DISSOLVE IN MORE AMMONIA. 






1 POUR WATER INTO A PINT JAR AND STIR INTO IT 1 TABLE- 
SPOON EARTH FROM THE GARDEN OR FROM A FLOWER POT. 

2 IN ANOTHER JAR, MAKE A SIMILAR MIXTURE. IN THIS, DIS- 
SOLVE Vt TEASPOON ALUM. ADD 1 TEASPOON AMMONIA. DIRT 
SETTLES FASTER IN THIS JAR THAN IN THE FIRST JAR. 





ALUM AND SODA 



1 TO >/, TEASPOON OF ALUM IN 20 ml 
WATER, ADD Vt TEASPOON SODA IN 20 
ml WATER. PRECIPITATE SHOULD BE CAR- 
BONATE — BUT IS IT? 

2 FILTER THE PRECIPITATE. WASH IT RE- 
PEATEDLY BY SQUIRTING WATER INTO IT. 

3 AFTER WASHING, BRING PRECIPITATE 
INTO A TEST TUBE. ADD HYDROCHLORIC 
ACID. NO CO, IS FORMED. THIS IS NOT 
A CARBONATE. ALUMINUM HAS NO CAR- 
BONATE. ALUM MAKES ALUMINUM HY- 
DROXIDE WITH SODA. 



65 



MANGANESE 
DIOXIDE TO 
MANGANESE 
SULFATE 




MANGANESE 
SULFATE TO 
MANGANESE 
HYDROXIDE 




1 IN A PYREX CUSTARD CUP, MIX 2 g MANGANESE DIOXIDE, 6 g SO- 
DIUM BISULFATE, AND 10 ml WATER. HEAT MIXTURE GENTLY. IT WILL 
BUBBLE VIGOROUSLY BECAUSE OXYGEN IS SET FREE. 

2 AFTER A FEW MINUTES, ADD 30 ml WATER. FILTER. FILTRATE CON- 
TAINS MANGANESE SULFATE (MnSO«) AND SODIUM SULFATE. 



3 INTO HALF OF THE MANGANESE SUL- 
FATE SOLUTION YOU HAVE MADE, POUR 
10% SOLUTION OF NaOH UNTIL NO 
MORE PRECIPITATE FORMS. WHITISH 
Mn(OH), OXIDIZES INTO BROWN MnO(OH). 



iViaiiganese — Nketal of JVIaiiy Ooiors 



Metallic manganese has no use by itself. But add 
up to 15 per cent of it to steel and the result is an 
alloy — "manganese steel" — so hard that it is suit- 
able for machine parts that are exposed to a lot of 
rough wear. 

The most common ore from •which manganese is 
extracted goes under the name of "pyrolusite." This 
is nothing but your old friend manganese dioxide 
(MnOj) which you found in your flashlight battery 



and have already used in a great number of your 
chemical experiments. 

The compounds of manganese come in almost any- 
color you can think of: black and brown, white and 
pink and red, violet and green. In working with 
these compounds, your fingers and glassware may 
get brown. You can get rid of this stain easily with 
diluted hydrochloric acid. Rinse thoroughly with 
water afterwards. 



EXPERIMENTS WITH POTASSIUM PERMANGANATE 

KMnO„ WILL GIVE YOU AN IDEA OF SMALLNESS OF MOLECULE. 

t.l ) DISSOLVE >/j g POTASSIUM PERMANGANATE IN 50 ml WA- 
TER. THIS GIVES A SOLUTION OF 1 TO 100, OR 1/100. 

DILUTE 5 ml OF THIS SOLUTION WITH 45 ml WATER. YOU 
)W HAVE A SOLUTION OF 1 TO 1,000, OR 1/1,000. 

AGAIN, 5 ml TO 45 ml WATER FOR SOLUTION 1/10,000. 

1 AGAIN, 5 ml TO 45 ml WATER FOR SOLUTION 1/100,000. 

'..5, AGAIN, 5 ml TO 45 ml WATER FOR SOLUTION 1/1,000,000. 
COLOR YOU STILL SEE IS CAUSED BY THE PRESENCE OF MORE 
THAN 600,000,000,000,000,000 MOLECULES OF KMnO„. 





REDUCING KMnO< 

PLACE A FEW CRYS- 
TALS OF POTASSIUM 
PERMANGANATE ON 
BOTTOM OF A TEST 
TUBE. DROP A FEW 
DROPS OF HYDRO- 
CHLORIC ACID ON 
THEM. THE KMnO« IS 
REDUCED (THAT IS, IT 
GIVES UP OXYGEN). IT 
OXIDIZES HCI AND 
SETS CHLORINE FREE. 



THE EXPERIMENTS ALONG THE 
TOP OF THESE PAGES SHOW 
HOW IT IS POSSIBLE TO 
MOVE FROM ONE COM- 
POUND TO ANOTHER. 



M 

M 



ANGANESE SULFATE TO 
MANGANESE CARBONATE 





MANGANESE 
CHLORIDE TO 
MANGANESE 
SULFIDE 



MANGANESE 

CARBONATE 

TO 

MANGANESE 

CHLORIDE 



tINTO SECOND HALF OF 
LUTION, POUR SOLUTION OF 
i g SODIUM CARBONATE IN 10 
ml WATER. WHITE PRECIPITATE 
IS MnCOj. 




m 



MANGA- 
E S E 

Element 25. 
Atomic wt.: 54.94. 
Density: 7.44. Sil- 
very-gray metal 
with reddish tinge. 
Reacts with water. 
Its compounds with 
oxygen range from 
bases to acids. 



5 LET MANGANESE CARBONATE 
SETTLE. POUR LIQUID OFF PRECIPI- 
TATE. ADD HYDROCHLORIC ACID BY 
THE DROP UNTIL DISSOLVED. RESULT 
IS MANGANESE CHLORIDE (MnCI,). 



■MP* 



6 SET UP APPARATUS FOR MAKING HY- 
DROGEN SULFIDE (SEE PAGE 53). POUR 
SOLUTION OF MnCI, INTO TEST TUBE. 
DILUTE IT IF NECESSARY. LEAD H,S INTO 
IT. YOU GET MANGANESE SULFIDE. 




^■^iy- 






DISSOLVE A FEW CRYS- 
TALS OF POTASSIUM 
PERMANGANATE IN 
WATER. ADD TINY 
AMOUNT OF SODIUM 
BISULFATE (TO MAKE 
SOLUTION SOUR). POUR 
IN A LITTLE HYDROGEN 
PEROXIDE (HjO,). COL- 
OR DISAPPEARS AND 
OXYGEN IS LIBERATED. 





1 1 , DISSOLVE 1 g SODIUM HYDROXIDE IN 50 ml WA- 
TER. ADD A CRYSTAL OF POTASSIUM PERMANGANATE 
TO GIVE THE SOLUTION A LIGHT RED COLOR. 

2 POUR THE RED SOLUTION INTO A FILTER. WATCH 
THE FILTRATE. IT IS GREEN INSTEAD OF RED. PASSING 
THROUGH FILTER PAPER HAS CAUSED KMnO« TO BE 
REDUCED TO POTASSIUM MANGANATE (K,Mn0 4 ). 



s 



^ -* 





1 DISSOLVE A SMALL CRYSTAL OF IRON 
SULFATE (FERROUS SULFATE, FeSG.) IN HALF 
A TEST TUBE FULL OF WATER. 

DISSOLVE A COUPLE OF KMnO„ CRYSTALS 
HALF TEST TUBE OF WATER. 

3 POUR PERMANGANATE INTO IRON SALT. 
GREEN FERROUS SULFATE IS OXIDIZED TO 
BROWN FERRIC SULFATE (Fe,(S0 4 ) 1 ). 



67 




TWO KINDS OF IRON COMPOUNDS 

IRON FORMS TWO KINDS OF COMPOUNDS. IN FERROUS 
SALTS, EACH IRON ATOM HAS REPLACED TWO HYDRO- 
GEN ATOMS. IN FERRIC SALTS, EACH IRON ATOM HAS 
REPLACED THREE HYDROGEN ATOMS. GREEN FERROUS 
SALTS EASILY OXIDIZE INTO RED-BROWN FERRIC SALTS. 




RUSTING OF IRON 

MOISTEN A WAD OF FINE STEEL 
V/OOL WITH VINEGAR (TO SPEED UP 
ACTION). WEDGE IT IN BOTTOM OF 
A GLASS. INVERT GLASS IN 
PIE PLATE OF WATER. IN A 
FEW DAYS, WATER HAS 
RISEN IN GLASS. IRON HAS 
REACTED WITH OXYGEN 
AND MOISTURE TO FORM 
RUST— (Fe 2 3 ),-3H 2 0. 



Iron metal has Ike peculiar quality of being mag- 
netic — that is, of being attracted and influenced by 
a force called magnetism. If you should walk around 
your home and touch different things with a mag- 
net, you would be surprised at the large number of 
them that would prove to contain iron. They would 
range in size from the car in the garage and the re- 
frigerator and stove in the kitchen to the nails in the 
walls and the needles and pins in your mother's 
sewing box. 

The moment you step outdoors and look around. 
you will be even more amazed. Skyscrapers and 



MAKING A FERRIC SALT 





MAKING A 
FERROUS SALT 

(f POUR HYDROCHLO- 
RIC ACID OVER STEEL 
WOOL. HYDROGEN IS 
SET FREE AS STEEL 
WOOL DISSOLVES. FIL- 
TER THE SOLUTION. 

2 LIGHT-GREEN FIL- 
TRATE CONTAINS FER- 
ROUS CHLORIDE (FeCI,). 



TEST FOR IRON SALTS 

(0 IN ONE TEST TUBE, DILUTE SOME FERRIC 
CHLORIDE SOLUTION WITH V/ATER. 

® IN ANOTHER, DILUTE SOME OF THE FER- 
ROUS CHLORIDE SOLUTION WITH WATER. 



SET UP APPARATUS FOR MAKING CHLORINE 
[SEE PAGE 35). INTO BOTTLE B POUR FER- 
ROUS CHLORIDE SOLUTION YOU HAVE JUST 
MADE. THE CHLORINE TURNS THE GREEN 
FERROUS CHLORIDE (FeCI 2 ) INTO A BROWN 
FERRIC CHLORIDE (FeCI 3 ). 



3 TO EACH, ADD A FEW DROPS 
OF SOLUTION OF >/ 4 TEASPOON 
POTASSIUM FERROCYANIDE IN 
50 ml WATER. FERRIC SALT MAKES 
A DEEP BLUE PRECIPITATE OF 
PRUSSIAN BLUE. FERROUS SALT 
MAKES LIGHT BLUE PRECIPITATE. 




68 






^^ILffi^^ 




bridges, railroads and ships, machinery of all kinds 
— all of these depend on iron (in the form of steel) 
for their existence. 

\\ e are very lucky to have, in America, not only- 
large amounts of iron ore but also large amounts of 
the coal from which to make the coke that goes into 
iron production. 

The iron is driven out of its ore (mostly Fe 2 3 ) 
in huge furnaces. Each furnace can make as much 
as 1.000 tons of iron at one time from 2.000 tons of 
ore, 1.000 tons of coke, and 500 tons of limestone. 
A blast of hot air is forced through the mixture. The 
coke burns with great heat to carbon dioxide. This, 
with more coke, forms carbon monoxide, and this, 
in turn, reduces the iron oxide to metallic iron. In 
chemical language, this is what happens: 

C + 0, — * C0 2 plus heat 

CO, + C — 2CO 

Fe,0, + 3CO — 2Fe + 3C0 2 

At the same time, the limestone combines with 
various impurities to form a glass-like compound 
called "slag." This is removed when the white-hot 
iron is poured out into moulds and cooled into bars 
of "pig iron." 

The pig iron is brittle because it contains close to 
5 per cent carbon. To turn it into steel, the carbon 
must bo burned out until only from .5 to 1.5 per cent 
remains. This is done either by the Bessemer process 
(named for an Englishman. Henry Bessemer) or by 
the open-hearth process. The finished steel is molded 
into "ingots" and shipped to manufacturing plants 
all over the country. 

In chemical experiments, the most commonly used 
iron compound is the iron sulfate (ferrous sulfate, 
FeS0 4 -7H 2 0) — also called "green vitriol" and 
"copperas." Don't let the last name mislead you — 
it has nothing to do with copper but comes from 
an old French word, conperose. 



FROM FERROUS 
SALT TO » 

FERRIC /]' 





J 



IRON HYDROXIDES 
AND CARBONATE 



1 DISSOtVE % TEASPOON FER- 
ROUS SULFATE IN 50 ml V/ATER. 
ADD A FEW CRYSTALS OF SODI- 
UM BISULFATE TO KEEP THE SO- 
LUTION SOUR. 

2 ADD HYDROGEN PEROXIDE 
SOLUTION. LIGHT-GREEN FER- 
ROUS SULFATE SOLUTION TURNS 
REDDISH-BROWN. H,0, HAS OX- 
IDIZED FeS0 4 TO FERRIC SULFATE 
(Fe 2 (SO<) 3 ). 




1 TO SOLUTION OF '/, TEASPOON FERROUS SULFATE 
IN 50 ml WATER, ADD SOLUTION OF SODIUM HYDROX- 
IDE. PURE FERROUS HYDROXIDE IS WHITE. BECAUSE OF IM- 
PURITIES, YOU GET DIRTY-GREEN PRECIPITATE OF Fe(OH)„ 
SOON OXIDIZING TO BROWN FERRIC HYDROXIDE. 

2 TO ANOTHER PORTION OF FERROUS SULFATE SOLU- 
TION ADD SODIUM CARBONATE SOLUTION. PURE CAR- 
BONATE MADE WITH NO OXYGEN PRESENT IS WHITE — 
BUT YOU GET MUDDY, WHITISH-GREEN PRECIPITATE OF 
FERROUS CARBONATE, EVENTUALLY TURNING INTO FER- 
RIC HYDROXIDE. 



69 







Chopper— Xesteraay, loday 

Copper is one of the few metals found free in na- 
ture. That is why it was used long before historic 
times for weapons and utensils. The main trouble 
with it was its softness. This was remedied when 
some early coppersmith discovered that copper and 
tin (also found free in nature) melted together formed 
an alloy that was much harder than either of the 
two metals. This alloy gave its name to more than 
two thousand years of human history — the period 
called the "Bronze Age." 

A great number of weapons from the Bronze Age 
have been found in Greece. When they were dug out 
of the ground, they were covered with a green "rust." 
This deposit was called verdigris — literally "green 
of Greece" (from old French, vert de Grece). It con- 
sists of hasic cupric carbonate — the same compound 
you will see on a bronze statue or a copper-clad 
church spire exposed to wind and weather. 

Copper became especially valuable less than a 
hundred years ago when a satisfactory method for 
producing a steady flow of electricity was invented. 
After silver, copper is the best conductor of electrici- 
ty. Today, the most important use for copper is for 
electrical purposes. It servrs to bring the current 
from the place where it is produced to the place 
where it is to be used (although, within recent years, 
some aluminum has taken its place for high-tension 



THE GREEK AND TROJAN WARRIORS FIGHTING BEFORE 
THE GATES OF TROY USED SWORDS AND SHIELDS OF 
BRONZE— AN ALLOY MADE UP OF COPPER AND TIN. 



wires). \ou will find copper in the wiring in your 
own home and in every electrical gadget you use. 

Copper makes two kinds of salts. In cuprous salts, 
one copper atom has taken the place of one hydrogen 
atom: in cupric salts, one copper atom has taken the 
place of two hydrogen atoms. Cuprous salts (such 
as cuprous chloride, CuCl) are colorless, while cupric 
salts (such as cupric sulfate, CuS0,'5H,0) are bright 
blue in color. 



MOST IMPORTANT USE 
OF COPPER TODAY IS 
FOR ELECTRIC WIRING. 




" 



70 



MAKING COPPER COMPOUNDS 




M 



: 



DISSOLVE 10 g COP- 
PER SULFATE IN 100 
ml WATER. POUR 10 
ml INTO EACH OF 
FOUR TEST TUBES. 



FROM CUPRIC 
SALT TO 
CUPROUS 
SALT 



*»— J 



\__^ 



3 



W- 



J 



1 10% SODIUM 
HYDROXIDE SOLU- 
TION PRECIPITATES 
DIRTY-BLUE CUPRIC 
HYDROXIDE 
(GafOHLj. 



2 WITH AMMONIA 
YOU'LL ALSO GET 
Cu(OH) 2 , BUT THIS DIS- 
SOLVES IN MORE AM- 
MONIA WITH DEEP BLUE 
COLOR. 



3 SODIUM CAR- 
BONATE SOLUTION 
GIVES BLUE-GREEN 
CUPRIC CARBON- 
ATE PRECIPITATE. 



4 WITH HYDRO- 
GEN SULFIDE, 
BROWNISH-BLACK 
PRECIPITATE OF 

CUPRIC SULFIDE. 





.1 LET CUPRIC HYDROXIDE (IN EX- 
PERIMENT ON TOP OF PAGE) SET- 
TLE. THEN POUR OFF LIQUID. ADD 
HYDROCHLORIC ACID UNTIL ALL IS 
DISSOLVED. ADD SMALL PIECES OF 
COPPER WIRE. HEAT TO BOILING. 




ft COPPER 
lj[| Element 29. 
Atomic wt.: 
63.54. Density: 
8.97. Soft metal of 
reddish color. Eas- 
ily rolled and 
drawn into wire. 
Next to silver.is the 
best conductor of 
electricity. 



2 POUR A FEW DROPS OF THE HOT SOLU- 
TION INTO A LARGE AMOUNT OF WATER. 
YOU GET A WHITE PRECIPITATE. WHEN YOU 
DISSOLVED CUPRIC HYDROXIDE IN HCI, YOU 
MADE CUPRIC CHLORIDE WHICH IS SOLUBLE 
IN WATER. BY TREATING THiS WITH METALLIC 
COPPER, YOU GOT CUPROUS CHLORIDE, IN- 
SOLUBLE IN V/ATER. 



COPPER SULFATE IN 
CHEMICAL ANALYSIS 

WATERFREE (ANHYDROUS) 
CUPRIC SULFATE SHOWS IF 
WATER IS PRESENT IN A 
LIQUID BEING TESTED. 

( 1/ CRUSH A FEW 
CUPRIC SULFATE 
CRYSTALS. HEAT 
WHILE STIRRING 
UNTIL THEY HAVE 
TURNED INTO A 
V/HITE POWDER. 

I SHAKE UP A LITTLE ANHYDROUS 
CUPRIC SULFATE WITH CARBON TET- 
RACHLORIDE. NOTHING HAPPENS. 

V) ADD ONE DROP OF WATER. 
SHAKE. BLUE CRYSTALS FORM. 



REPLACING COPPER WITH IRON 




(l ■' drop several clean nails 
into a solution of copper sul- 
fate, leave for half an hour. 

1.2) nails are now coated with 
Metallic copper and the solu- 
tion CONTAINS FERROUS SULFATE. 

METALS CAN BE ARRANGED IN A 
REPLACEMENT SERIES. ANY METAL 
IN THE SERIES V/ILL DRIVE OUT AN- 
OTHER METAL BELOW IT AND TAKE 
ITS PLACE IN THE SALT. 



REPLACEMENT 
SERIES 

POTASSIUM 

SODIUM 

CALCIUM 

MAGNESIUM 

ALUMINUM 

ZINC 

CHROMIUM 

IRON 

NICKEL 

TIN 

LEAD 

COPPER 

MERCURY 

SILVER 

PLATINUM 

GOLD 



71 



SILVER IS MALLEABLE — 
THAT IS, IT CAN BE HAM- 
MERED INTO ANY SHAPE 
DESIRED. SILVER SMITHING 
IS AN ANCIENT ART. 




il Ter _One of tlxe "Nolle" Metal 



SILVER 

Element 47. 

Atomic wt.: 
107.880. Density: 
10.54. Soft, white 
metal with bright 
luster. Easily ham- 
mered out and 
drawn into wire. 
Best known conduc- 
tor of electricity. 




Silver — like copper and gold — is found free in 
nalure and was therefore known to man long before 
he learned to exlract metals from their ores. 

Pure silver has one drawback — it is almost as 
soft as copper. That's why most silver is alloyed with 
copper to make it harder. Sterling silver — a famous 
alloy used for jewelry — contains 7.5 parts copper to 
92.5 parts silver. Only 36 of American silver coins 
is silver — the rest is copper. 

When you take a snapshot, you get yourself in- 
volved in a series of complicated, chemical processes 
— all of them having to do with silver. It is hard 
to believe that the blacks and grays you see when 
you look at a photograph are various concentrations 
of metallic silver. 

REMOVING TARNISH FROM SILVER 

.1 LINE BOTTOM OF CUSTARD CUP WITH ALUMINUM 
FOIL. PLACE TARNISHED COIN ON FOIL. POUR CUP HALF 
FULL OF V/ATER. ADD '/ 4 TEASPOON SODIUM CARBON- 
ATE. BOIL GENTLY. TARNISH VANISHES. 

2 YOU CAN USE THIS METHOD FOR CLEANING SILVER- 
WARE. PLACE SILVER TO BE CLEANED IN ALUMINUM TRAY. 
ADD WATER AND SODA. BRING TO A BOIL. THE SILVER 
BECOMES SHINY AGAIN. 



TARNISHED SILVER 

SILVER TARNISHES WHEN IT IS EX- 
POSED TO SULFUR. PLACE A FEW 
CRYSTALS OF SODIUM THIOSULFATE 
("HYPO") ON A SILVER COIN. HEAT 
UNTIL HYPO MELTS. WASH. HYPO 
HAS LEFT STAIN OF BROWN-BLACK 
SILVER SULFIDE. 




SILVER 
COMPOUNDS 



GET 5 g SILVER NITRATE IN YOUR LOCAL 
DRUG STORE. DISSOLVE IN 50 ml WATER. 










1' TO 5 ml SILVER NITRATE (AgNO,) SOLUTION, 
ADD SODIUM HYDROXIDE SOLUTION. YOU GET 
DARK-BROWN PRECIPITATE— NOT OF HYDROXIDE, 
BUT OF SILVER OXIDE. 

2 TO 5 ml AgNO, SOLUTION, ADD AMMONIA. 
PRECIPITATE OF SILVER OXIDE DISSOLVES WHEN 
YOU ADD MORE AMMONIA. 

3 TO 5 ml AgNO, SOLUTION, ADD TABLE SALT 
(NaCI) SOLUTION. CHEESELIKE PRECIPITATE IS SIL- 
VER CHLORIDE (AgCI). 

4 TO PART OF AgCI PRECIPITATE, ADD AMMONIA. 
SILVER CHLORIDE DISSOLVES. 

5 TO ANOTHER PART OF AgCI, ADD SODIUM 
THIOSULFATE SOLUTION. AgCI DISSOLVES. 

6 PLACE REMAINING AgCI IN THE SUN. IT TURNS 
VIOLET FROM METALLIC SILVER. 



72 




In making a photographic film, the manufacturer 
spreads an emulsion of gelatin that contains silver 
bromide (AgBr) over a transparent sheet of cellulose 
acetate. When the silver bromide is exposed to fight, 
a certain amount of it gives up metallic silver (AgBr 
— Ag + Br). More of this silver is brought out in 
the developing bath. When fully developed, the film 
is placed in a fixing bath which removes all unexposed 
silver bromide. After washing and drying, you have 
a photographic negative in which the white parts 
you photographed appear black and the black parts 
appear white. 

To make a natural-looking picture, you place the 
negative on a piece of photographic paper and go 
through a similar procedure, as above, of exposing, 
developing, fixing, washing, and drying. 



MORE THAN 1 50 
TONS OF SILVER ARE 
USED EACH YEAR IN 
MAKING FILM FOR 
THE MOVIES. 



PHOTOGRAPHY IN- 
VOLVES A WHOLE 
SERIES OF CHEMI- 
CAL PROCESSES. 





PHOTOGRAPHING WITHOUT A CAMERA 




2 FIX THE LEAF PRINT IN A SO- 
LUTION OF 10 g HYPO IN 100 m 
WATER. AFTER FIVE MINUTES, 
WASH IN RUNNING WATER. 



tFROM A COMMERCIAL PHOTOGRAPHER, GET A 
SHEETS OF "PRINTING-OUT PAPER," A SLOW 
PHOTOGRAPHIC PAPER. IN THE SHADE, PLACE SHEET 
ON PIECE OF PLYWOOD, SENSITIZED SIDE UP. ON 
TOP OF IT, LAY A LEAF AND A SHEET OF GLASS. 
HOLD IN POSITION WITH SPRING CLOTHES PINS. 
EXPOSE TO SUN UNTIL PAPER IS BLACKISH-VIOLET. 



3 DRY THE PRINT 
IN THE AIR ON TOP 
OF NEWSPAPER. 
WHEN DRY, FLATTEN 
PRINT IN A BOOK. 



73 





USING PATTERNS AT LEFT, CUT OUT SEVERAL CIRCLES 
OF CONSTRUCTION BOARD IN VARIOUS COLORS. 



TRACE EACH OF THE CIRCLES SHOWN ABOVE ONTO 
CARDBOARD. PUNCH HOLES AS INDICATED. USE AS PAT- 
TERNS FOR CUTTING CIRCLES OF CONSTRUCTION BOARD. 



PUNCH THE HOLES NECESSARY TO INDICATE VALENCES. 



Val 



emees ail 

As you have studied the chemical formulas in the 
text, you will have noticed that one atom of hydro- 
gen combines with one atom of chlorine (HC1), two 
hydrogen atoms with one atom of oxygen (H2O). 
and three hydrogen atoms with one atom of nitrogen 
(NH,). 

The capacity of one atom to hold on to other atoms 
is called its valence (from Latin valeniia, strength). 



<ol Jr ©fshtulJU 



©Finuiias 

No atom has a lower valence than the hydrogen 
atom, so we use hydrogen as our starting point and 
give it a valence of 1. Two hydrogen atoms combine 
with one oxygen atom — that gives oxygen a valence 
of 2. Nitrogen has a valence of 3. Two oxygen atoms 
combine with one carbon atom to make COj. Carbon 
has a valence of 4. 

The chart on page 75 shows some of the common 




THESE DIAGRAMS SHOW WHAT HAPPENS WHEN YOU 
BURN CARBON AND TEST FOR CO,. ONE CARBON 
ATOM (WITH FOUR POSITIVE VALENCES) COMBINES 
WITH TWO ATOMS OF OXYGEN (EACH WITH TWO 
NEGATIVE VALENCES) TO FORM ONE MOLECULE OF 
CO, (ARROW POINTING UP INDICATES THAT THIS IS 
A GAS). ONE MOLECULE CARBON DIOXIDE COMBINES 
WITH ONE MOLECULE CALCIUM HYDROXIDE TO FORM 
ONE MOLECULE OF CALCIUM CARBONATE (ARROW 
POINTING DOWN INDICATES THAT IT IS A PRECIPI- 
TATE) AND ONE MOLECULE OF WATER. 




74 




PUT '/„" BRASS CLIPS IN HOLES SHOWING POSITIVE VA- 
LENCES. HOLD THEM IN PLACE WITH SCOTCH TAPE. 




WRITE THE NAMES OF THE ELEMENTS WITH CRAYONS. 





SOME 


COMMON VALENCES 






Positive Valences 


Negative Valences 




Item 


Valence 


Circle 


Item Valence 


Circle 




Ag 


+ 1 


A 


CI —1 


A 




Al 


+ 3 


C 


1 —1 


A 




B 


+ 3 


C 


N —3 


B 




C 


+ 4 


C 


O —2 


B 




Ca 


+ 2 


6 


S —2 


C 




Cu 


+ 1+2 


B 








Fe 


+ 2 + 3 


B 








H 


+ 1 


A 








K 


+ 1 


A 








Mg 


+ 2 


B 








Mn 


+ 2 


B 


CO, —2 


B 




Na 


+ 1 


A 


NO, —1 


A 




S 


+ 4 + 6 


C 


OH —1 


A 




Si 


+ 4 


C 


SO, —2 


B 




NH 4 


+ 1 


A 


SO, -2 


B 





valences for making up formulas. Most of the items 
are elements, but some of them are "radicals" — that 
is, groups of atoms that hang together in chemical 
reactions, such as the ammonium radical (SH,) that 
behaves as a metal, and the sulfate radical (SO.) 
that goes into the making of salts. 

Notice that some valences have plus (+) signs, 
others have minus ( — ) signs. When you make up 
the formula for a compound, there must be the same 
number of pluses and minuses. Hydrogen with one 




SULFUR HAS SEVERAL VALENCES. IT HAS A VALENCE 
OF -2 IN H,S, OF +4 IN SO,, AND OF +6 IN SO, 
AND IN SULFURIC ACID (H,SO.,). IN MAKING THE CIR- 
CLE FOR SULFUR, YOU CAN SHOW THESE VALENCES 
WITH TWO EMPTY HOLES AND SIX BRASS CLIPS. 

INSTEAD OF USING ONE SULFUR CIRCLE AND FOUR 
OXYGEN CIRCLES TO INDICATE A SULFATE, YOU CAN 
MAKE UP A SINGLE CIRCLE TO STAND FOR THE SUL- 
FATE RADICAL (SO«) WITH TWO NEGATIVE VALENCES. 



plus (^H-)and oxygen with two minuses (0 — ) would 
not fit together — you need H 2 to combine with 0. 
Similarly, C with + -1 (C++++) takes two 0, each 
with — 2 (0 — ), in order to balance. 

To get a clear understanding of chemical formulas, 
make yourself a set of atom models as shown on 
these pages. With these models you will be able to 
figure out how compounds are made up and what 
happens in the various chemical reactions you will 
cause in your experiments. 




75 




A LANDSCAPE IN THE COAL AGE, APPROXIMATELY THREE HUNDRED MILLION YEARS AGO. 



v^arbon — icJenient 01 a iVIo 



1011 



c 



To the old ROMANS, carbo meant coal — a black 
rock that would burn. To the modern chemist, car- 
bon is an element found in all living things — plants 
and animals — and in many dead things. It is hidden 
in the whitest sugar and the reddest rose and the 
greenest apple, in hundreds of thousands of com- 
pounds produced by nature and in many thousands 
more created in the laboratory. 

The soot from a smoking candle is almost pure 
carbon. So is also the graphite that forms the "lead" 
of your pencil and the diamond in the jeweler's win- 
dow. The coal that we use for fuel contains from 80 



onipouiids 

to 90 per cent carbon — the other 10 to 20 per cent 
is made up of various substances from which a 
great number of important and valuable chemical 
compounds are made. 

All the coal we mine deep underground today is 
made up of the remains of plants that grew around 
three hundred million years ago — huge tree ferns, 
giant club mosses and horsetails. They thrived in 
the hot, humid climate, died and tumbled to the 
ground. During the ages they were covered by other 
dead trees and by layers upon layers of mud. Even- 
tually, pressure and heat turned them into coal. 



PRESSURE AND HEAT TURNED TREES AND OTHER PLANTS INTO THE COAL WE USE TODAY. 




76 



CC A R B O N 
Element 6. 
Atomic wt.: 
12.011. Found in 
nature as diamond 
(density 3.52), as 
graphite (density 
2.25), and as coal. 
Diamond burns in 
oxygen, coal in air. 



THREE FORMS OF CARBON 



lignite 




GRAPHITE IS A SOFT FORM OF 
CARBON. IT FEELS SLIPPERY. 



rough 
diamond 



gra 



uses of graphite 



bituminous coal 

ANTHRACITE IS ALSO CALLED HARD COAL. BITUMINOUS COAL IS SOFT COAL. LIGNITE IS BROWN COAL 
GRAPHITE IS A SOFT FORM OF CARBON. IT FEELS SLIPPERY. DIAMOND IS THE HARDEST SUBSTANCE KNOWN. 




DESTRUCTIVE DISTILLATION ^ — 

IN REGULAR DISTILLATION (SEE PAGE 61), A 
CHEMICAL IS PURIFIED. IN DESTRUCTIVE OR 
DRY DISTILLATION, THE SUBSTANCE IS BRO- 
KEN INTO SEVERAL DIFFERENT CHEMICALS. 



for dry distillation of coal, crush lump 
of bituminous coal into powder. 



t^-yOaSEP 





for dry distillation of 
wood, whittle twig into 
slivers, or use wooden 
matches without heads. 



^^ 



7 




I 



CARBON 
SUGAR 




1^ L J, E ,wlJ,V BE U FUlL OF COARSELY POWDERED BITUMINOUS COAL (OR 
^?P. S A IVERS1 - PLACE SMALl WAD OF COTTON AT MOUTH OF TEST TUBE 
CLOSE MOUTH OF TUBE WITH STOPPER WITH L-SHAPED GLASS TUBE DRAWN TO 
AJET POINT. PLACE TUBE HORIZONTALLY IN HOLDER. HEAT COAL (OR WOOD). 

AFTER A WHILE, DENSE FUMES DEVELOP. THEY CAN BE IGNITED AT JET. 

COTTON WAD DISCOLORS FROM TAR CONDENSING AFTER BEING DISTILLED. 

annr?™"™! 1 ^ 5lfl\ OVE STOPPER - BRIN G MOISTENED LITMUS PAPER TO 
uSmL ?t V£*5k f YOU DISTIUED COAL, RED LITMUS TURNS BLUE FROM AM- 
f°^J A )-J F Y °U DISTILLED WOOD, BLUE LITMUS TURNS RED FROM ACETIC 
ACID (B). COAL HAS TURNED TO COKE, WOOD HAS BECOME CHARCOAL. 



YOU CAN PROVE PRESENCE OF 
CARBON IN THE FOOD YOU EAT 
BY HEATING SMALL SAMPLES OF 
CHEESE, BREAD, MEAT, SUGAR. 
BE SURE TO DO THIS OUTDOORS 
TO PREVENT EXPERIMENTS FROM 
SMELLING UP THE WHOLE HOUSE 



HEAT 1 TEASPOON CANE SUGAR IN A CUSTARD 
CUP. FIRST, SUGAR MELTS. THEN IT TURNS BROWN 
—IT "CARAMELIZES." NEXT IT GIVES OFF THICK 
VAPORS THAT CAN BE IGNITED. FINALLY A PURE 
FORM OF COAL REMAINS. 





RUB A LUMP OF SUGAR 
WITH CIGARETTE ASHES 
(TO ACT AS CATALYST). 
IGNITE. DIP TEST TUBE 
IN LIME WATER. HOLD 
OVER BURNING SUGAR. 
FILM OF CALCIUM CAR- 
BONATE SHOWS CO, 
IN FLAME — PROVING 
THAT THERE IS CARBON 
IN SUGAR. 



77 













IT WAS ONCE BELIEVED THAT ORGANIC COMPOUNDS 
COULD BE PRODUCED ONLY BY LIVING ORGANISMS. 



IN 1828, FRIEDRICH WOHLER SUCCEEDED IN MAKING AN 
ORGANIC COMPOUND ARTIFICIALLY IN HIS LABORATORY. 



1 ike Oihemisfpy ©J: Oarbon Compounds 



The chemists of about two hundred years ago di- 
vided all compounds very neatly into two groups — 
organic and inorganic. The organic compounds were 
those produced by living organisms — that is, plants 
and animals. The inorganic compounds were made 
up of dead things — rocks and minerals, water and 
various gases. Xo organic compound, these chemists 
insisted, could ever be produced artificially — they 
required the force we call "life" for their creation. 
And then, in 1828, a German chemist, Friedrich 
Wohler, completely upset this idea. 

In his laboratory, Wohler had mixed ammonium 
sulfate((NH ( ) 2 S0 4 ) and potassium cyanate (KCXO), 
expecting to get ammonium cyanate. After evapo- 
rating, he analyzed the compound he had made. To 
his amazement he discovered that it was not am- 
monium cyanate at all, but urea — a compound pro- 
duced in the kidneys of living animals, including 
man. The atoms of the ammonium cyanate molecule 
had rearranged themselves into a urea molecule. 

NH, CNO had turned into (iNH 5 ),CO. 



A few years later, another organic compound — 
acetic acid — was made artificially. And then the lid 
really blew off. More and more products of plant and 
animal life were put together — synthesized — in the 
laboratory. And as if this were not enough, chemists 
began producing organic compounds that were not 
even found in nature. 

It became clear that the old meaning of organic 
chemistry no longer was right. And so, the definition 
was changed. Today, organic chemistry is defined as 
"the chemistry of the carbon compounds." This defi- 
nition is almost, but not 100 per cent, correct. The 
metallic carbonates, for instance, are still considered 
to be inorganic compounds, and carbon dioxide and 
carbonic acid are regarded as being both organic and 
inorganic. 

You may think it odd that a whole branch of 
chemistry should deal with the compounds of a sin- 
gle element. But you will not be surprised at all when 
you start experimenting with a few of the close to 
1,000,000 carbon compounds. 



78 



HYDROCARBONS CONTAIN TWO ELEMENTS ONLY: FEW ATOMS TO THEIR MOLECULES ARE GASES. OTH- 
CARBON AND HYDROGEN. HYDROCARBONS WITH ERS WITH MANY ATOMS ARE LIQUIDS AND SOLIDS. 




Turpentine 



ALCOHOLS MAY BE CONSIDERED HYDROCARBONS CARBOHYDRATES ARE IN MANY OF OUR MOST VAL- 
IN WHICH A HYDROGEN ATOM IS REPLACED BY OH. UABLE FOODSTUFFS AS STARCH AND SUGARS. 




Ai 



Ethyl 

Alcohol 



Propvl 
iMcohol 





ESTERS IN ORGANIC CHEMISTRY CAN BE COMPARED 
TO SALTS IN INORGANIC CHEMISTRY. FATS AND OILS 



ARE THE MOST IMPORTANT ESTERS. THESE ARE THE 
"SALTS" OF GLYCERINE AND FATTY ACIDS. 




A 



Cookinf 
Oil 



Cailor 
Oil 




7" 

Oil 
of 

Winter- 
green 



CARBOXYLIC ACIDS ARE NAMED FOR THE CARBOXYL 
GROUP — COOH — FOUND IN THEIR FORMULAS. 



PROTEINS ARE COMPLEX COMPOUNDS THAT CON- 
TAIN CARBON, HYDROGEN, OXYGEN, NITROGEN. 




OTHER CARBON COMPOUNDS — IN ADDITION TO 
THE MAIN GROUPS ILLUSTRATED ABOVE, THERE ARE 



NUMEROUS OTHER KINDS OF CARBON COMPOUNDS. 
MANY HAVE VERY COMPLICATED FORMULAS. 




79 



sfhane, CH 4 ethane, C,H t 



ethylene, C 2 H 4 



acetylene, CjH, 



1 he Jr oirminuilas ot C^airlboii i^ompounds 



How is it possible for carbon to make so many dif- 
ferent compounds of such tremendous variety? That 
was one of the great questions facing chemists during 
the last century. 

It was easy enough to explain carbon dioxide. Car- 
bon has a valence of 4, oxygen of 2 — the formula 
had to be C0 2 . It was also easy to explain the mole- 
cule of the simple hydrocarbon methane (CH ( ). But 
how explain compounds consisting of two atoms of 
carbon and six of hydrogen (C,H 6 , ethane), or two 
atoms of carbon and four of hydrogen (C,!!,, ethyl- 
ene), or two of carbon and only two of hydrogen 
(C 3 H,, acetylene)? 

A German chemist and professor, Friedrich August 
Kekule, came up with the solution. The answer was 
quite simple: 

While the atoms of most elements "hook on" to 
the atoms of other elements according to their val- 
ences, the atoms of carbon "hook on" to each other 
as well. To understand this, write out carbon atoms 



with four lines to indicate the valence bonds, but 
arrange the lines in these three different ways: 

Then hook them together, two by two, in these three 
different ways: 

= C-C==C=C= -C=C- 
Now add a hydrogen atom to each of the free bonds 
— and there you have the formulas for the three 
hydro-carbons — ethane (C 3 H 6 ), ethylene (CjH,), 
and acetylene (C,Hj) : 



H 



\ 



/ 



H 



H-C-C— H 



II\ r _ r /H 



II— C=C-H 

h/ Ni 

So far so good. But there were still many carbon 
compound formulas that would not line up in this 
kind of arrangement. C 6 H 6 , for instance — benzene, 
an important hydrocarbon obtained by distillation 
of coal. 

Again, it was Kekule who offered the explanation. 
This time it came to him in a dream. He had been 



V ' i 

m&d ■■■■■■ 




KEKULE'S 

BENZENE 
RING 



H 



\ 



I 



i 



H 



AUGUST KEKULE HIT UPON THE 
STRUCTURE OF THE BENZENE MOLE- 
CULE IN A DREAM. A SNAKE SEEMED 
TO WHIRL IN A RING BEFORE HIS 
EYES. BY ARRANGING THE SIX CAR- 
BON ATOMS IN A RING, THE PROB- 
LEM WAS SOLVED. 






IN A CARBON ATOM (A), THE FOUR VALENCE BONDS 
POINT AWAY FROM THE CENTER (NUCLEUS) TOWARD 
THE CORNERS OF A TETRAHEDRON— A FIGURE MADE 
UP OF FOUR TRIANGLES. IN MODELS OF CARBON ATOMS, 
VALENCE BONDS ARE SHOWN BY RODS {B). 



TWO LABORATORY MODELS 
SHOWING THE METHANE 
MOLECULE. 



YOUR OWN MODEL OF 
METHANE MOLECULE. 



working all day with long lines of organic formulas. 
In the evening he dozed before the fire. In his dream, 
the lines of formulas turned into snakes, twisting and 
twining — until suddenly one of the snakes grasped 
its own tail and whirled around in a ring. This dream 
gave Kekule the clue: the carbon atoms in benzene 



hang together in a ring, each atom using three of its 
bonds to hang on to the atoms next to it, with one 
bond free to hook onto a hydrogen atom. 

Starting from these very simple formulas, modern 
scientists can figure out the most complicated chemi- 
cal formulas. 




YOU CAN THINK OF THE BENZENE RING 
AS SIX MONKEYS HANGING ON TO 
EACH OTHER WITH ONE OR TWO 
HANDS, HOLDING BANANAS IN THEIR 
FREE HANDS. 



THIS IS THE WAY THE BENZENE MOL- 
ECULE LOOKS WHEN IT IS CON- 
STRUCTED FROM PARTS USED TO 
MAKE UP LABORATORY MODELS FOR 
DEMONSTRATION. 



THIS IS HOW THE BENZENE MOLE- 
CULE WILL LOOK WHEN YOU P' 
TOGETHER FROM HOME-MADE 
BON ATOMS. YOU CAN DO 
WITH SCOTCH TAPE. 



.'■ 



81 




THE FIRST SUCCESSFUL OIL 
WELL, TITUSVILLE, PA., 1859. 






mm^ 




THE FIRST JOB OF 
THE OIL REFINERY 
IS TO SPLIT UP THE 
OIL INTO THE PARTS 
(OR FRACTIONS) OF 
WHICH IT CON- 
SISTS. THIS IS DONE 
IN TALL TOWERS. 
THE OIL IS HEATED. 
THE VAPORS RISE 
IN THE TOWER. 
THE LIGHTEST FRAC- 
TIONS— GAS AND 
GASOLINE— GO 
TO THE TOP, FOL- 
LOWED BY KERO- 
SENE, FUEL OIL, LU- 
BRICATING OILS, 
WAX, ASPHALT. 







CRUDE OH 



Wt3 



A HUNDRED YEARS AFTER THE FIRST OIL WELL IN PENN- 
SYLVANIA, OIL FIELDS ARE FOUND IN SEVERAL STATES. 

A JL/o£ of Oyajrocaroons 

The family car stops at the service station. 

"Fill 'er up!" The attendant pours what may be 
a hexane-septane-octanc-nonane mixture into the gas 
tank. "Cheek your oil. mister?" Into the engine goes 
another hydrocarbon mixture — possibly along the 
line of CjoH 4 }-C 21 H..-C5 2 H, 6 . And so you take off— 
on hydrocarbon tires. Yes, gasoline, motor oil, and 
rubber are all hydrocarbons — compounds that con- 
tain only hydrogen and carbon. 

A great number of hydrocarbons come from pe- 
troleum (crude oil). Coal and natural gas provide 
several others. Many more are produced by nature 
— natural rubber, turpentine, camphor, to mention 
a few. Even the red coloring of tomatoes and the 
yellow of carrots are hydrocarbons. 

One of the remarkable things about hydrocarbons 
is that it is possible to combine some of those with 
small molecules into others with larger ones (as in 
making synthetic rubber), as well as to "crack" those 
with large molecules into others with smaller ones 
(as when a heavy oil is "cracked" into gasoline). But 
that is only the beginning. By replacing one or more 
hydrogen atoms with hydroxy] groups (OH) or car- 
boxyl groups (COOH) or chlorine atoms (CI), for in- 
stance, it is possible to build up more complicated 
compounds — which can then be built up further and 
further. And that is exactly what chemists are doing 
today — giving us medicines and dyes, plastics and 
explosives, and countless other things. 



82 



1 HAMMER LUMPS OF 
BITUMINOUS COAL INTO 
A COARSE POWDER. FILL 
FUNNEL WITH IT. BRING 
FUNNEL INTO LARGE JAR. 

2 TURN JAR UPSIDE 
DOWN. FILL JAR WITH 
WATER. PLACE A WATER- 
FILLED TEST TUBE OVER 
FUNNEL. IN A FEW DAYS, 
TUBE IS FILLED WITH 
METHANE. 



METHANE CH„ 





IN THE LABORATORY, METHANE IS MADE BY HEATING 
WATER-FREE SODIUM ACETATE WITH "SODA LIME." 

(t ) TO MAKE SODIUM ACETATE, ADD WASHING SODA 
TO Vi CUSTARD CUP VINEGAR UNTIL NO MORE CO, IS 
GIVEN OFF. EVAPORATE MIXTURE AT LOW HEAT TO GET 
WHITE POWDER OF SODIUM ACETATE. 



>&' MIX 5 g SODIUM ACETATE (CH,COONo), 5 g SODIUM 
HYDROXIDE, AND 5 g CALCIUM OXIDE. DROP INTO TEST 
TUBE. SET UP APPARATUS FOR COLLECTING GAS AS 
SHOWN BELOW. HEAT TO MAKE METHANE: 

CH 3 COONa + NaOH -» CH 4 + Na a CO, 




USED IN MAKING MOTH BALLS. 

NAPHTHALENE CAN BE PURIFIED BY SUBLIMATION. 
TO DEMONSTRATE THIS, CRUSH A COUPLE OF MOTH 
BALLS. HEAT THEM IN A CUSTARD CUP. FIRST THEY 
MELT, THEN GIVE OFF YAPOR. PUT JAR FILLED WITH 
ICE WATER OVER CUP. NAPHTHALENE SETTLES ON 
BOTTOM IN LEAFY CRYSTALS. 



TURPENTINE— 




CRACKING OIL 

POUR A FEW ml HOUSEHOLD 
OIL IN TEST TUBE. PLACE 
WAD OF STEEL WOOL NEAR 
MOUTH OF TUBE. CLOSE IT 
WITH STOPPER THAT HAS A 
GLASS TUBE WITH JET TIP. 
HEAT STEEL WOOL. A LITTLE 
LATER, ALSO HEAT THE OIL. 
OIL IS CRACKED INTO GAS 
THAT BURNS WHEN IGNITED. 




1 POUR A LITTLE TURPENTINE INTO A 
BOTTLE CAP. PLACE A SMALL WICK IN IT. 

fa) PLACE BOTTLE CAP ON PIECE OF PAPER. 
IGNITE TURPENTINE. IT BURNS INCOMPLETE- 
LY, GIVING OFF A BLACK SMOKE OF CARBON 
WHICH YOU CAN COLLECT IN A JAR. 



83 




MUCH OF THE SUGAR WE USE IS MADE BY EVAPORATING .-^ff^p&P? 2 - 
THE JUICE OF SUGAR BEETS AND SUGAR CANE. MAPLE ^'5f^v£^ 
SUGAR IS BOILED-DOWN SAP OF SUGAR AMPLE TREES. -^§5^;^^ 



(carbohydrates — oweet and. Jhilaiid. 



Usually, when we talk about '"hydrates" we mean 
chemicals that contain water. But when we talk 
about carbohydrates we mean organic compounds of 
carbon, hydrogen, and oxygen in which the propor- 
tion between hydrogen and oxygen is the same as in 
water (H 2 0) — that is, twice as much hydrogen as 
oxygen. And so we find carbohydrates that have 22 
atoms of hydrogen and 11 atoms of oxygen to 12 
atoms of carbon (CuHjsO,,). or 12 hydrogen and 6 



THE SWEETNESS OF FRUITS AND 
BERRIES COMES FROM A MIXTURE 
OF TWO KINDS OF SUGAR CALLED 
FRUCTOSE AND GLUCOSE. THESE 
SUGARS ARE MADE IN THE GREEN 
LEAVES OF THE PLANT AND SENT 
INTO THE FRUITS FOR STORAGE. 








oxygen to 6 carbon (C 6 H 15 6 ), or 10 and 5 to 6 car- 
bon atoms (C 6 H I0 O s ). 

Carbohydrates are produced by plants by a re- 
markable process called photosynthesis — "putting 
Ihings together with the help of light." W hen green 
leaves are exposed to sunlight, the chlorophyll in 
them combines the hydrogen from water with carbon 
dioxide Cram the air, while setting oxygen free — 
along this line: 

6ILO + 6CO, + sunlight — C 6 II, s O s + 60, \ 

Carbohydrates are of tremendous importance to 
all of us. They make up a large part of our food 
supply in the form of sugars and starches. Another 
carbohydrate called cellulose helps to clothe us (cot- 
ton, linen) and shelter us (wood). 
ST. GARS — Most of our sugar comes from sugar 
beets or sugar cane. The juice is pressed out. cleared, 
filtered, and evaporated. The result is pure, white 
crystals of a sugar with the chemical name sucrose 
(C 15 H, 2 0„). 

Another sugar called glucose (C 6 H ]5 6 ) is found 
iu ripe fruits, often in the company of still another 
sugar of the same formula called fructose (C 6 H,,0 6 ). 
Those two sugars can be made in the laboratory by 
treating the more complicated sucrose with an acid. 
The sucrose picks up water and splits into glucose 
and fructose by a process known as inversion: 
C 13 II,,O n + II 2 — C 6 H„0 6 + C«H K 0, 
(sucrose) (glucose) (fructose) 

(CONTINUED ON PAGE 86) 




TEST FOR 
GLUCOSE 
SUGAR 





« 



COPPER 
SULRtfE 



A GERMAN SCIENTIST, HERMAN FEHL1NG, THOUGHT UP THE TEST 
FOR GLUCOSE THAT HAS HIS NAME. FOR THIS TEST, TWO SOLU- 
TIONS ARE REQUIRED. THEY ARE MIXED JUST BEFORE USE. 

1 FEHLING A. DISSOLVE 5 g COPPER SULFATE IN 70 ml WATER. 

1. FEHLING B. DISSOLVE 7 g SODIUM HYDROXIDE IN 70 ml WA- 
TER. IN THIS SOLUTION, DISSOLVE 25 g ROCHELLE SALT (SODIUM- 
POTASSIUM TARTRATE) FROM YOUR LOCAL DRUG STORE. 





HEAT A MIXTURE OF 
2 ml FEHLING A AND 
2 ml FEHLING B IN 
A TEST TUBE. ADD A 
FEW DROPS OF SOLU- 
TION TO BE TESTED. 
HEAT AGAIN. RED PRE- 
CIPITATE OF CUPROUS 
OXIDE (Cu 2 OJ SHOWS 
GLUCOSE IS PRESENT. 




USE FEHLING TEST TO FIND OUT IF DIFFERENT SWEET- 
TASTING FOODS CONTAIN GLUCOSE SUGAR: CORN SYRUP, 
MAPLE SYRUP, MOLASSES, HONEY. ALSO TRY JUICES OF 
VARIOUS FRUITS: PRUNES, ORANGES, LEMONS, BERRIES. 
SEVERAL CONTAIN GLUCOSE AND GIVE RED PRECIPITATE. 
SUGAR IN MILK (LACTOSE) GIVES Cu a O PRECIPITATE. 



TEST CANE SUGAR WITH FEHLING. YOU DO NOT 
GET RED PRECIPITATE. CANE SUGAR IS NOT 
GLUCOSE BUT ANOTHER SUGAR CALLED SUCROSE. 




1 DISSOLVE 1 g CANE SUGAR IN 10 ml WATER IN A 
TEST TUBE. ADD 10 DROPS HYDROCHLORIC ACID. 
HEAT GENTLY FOR A FEW MINUTES WITHOUT BOILING. 

'2; HEAT FEHLING SOLUTION IN ANOTHER TEST TUBE. 
ADD A FEW ml SUGAR SOLUTION. HEAT AGAIN. YOU 
GET RED PRECIPITATE. GLUCOSE HAS BEEN FORMED. 



MAKING SUGAR CANDY 

IT IS EASY TO MAKE LOLLIPOPS. 
OVER LOW HEAT AND WHILE STIR- 
RING, DISSOLVE '/j CUP SUGAR IN 
2 TABLESPOONS WATER AND 2 TA- 
BLESPOONS LIGHT SYRUP. THEN 
CONTINUE HEATING WITHOUT STIR- 
RING UNTIL A SAMPLE DROPPED 
INTO COLD WATER FORMS BRITTLE 
THREAD. SPOON OUT TABLESPOON- 
FULS ONTO A SHEET OF GREASED 
ALUMINUM FOIL. PUSH STICK IN 
EACH BLOB. REMOVE WHEN COLD. 



Perform this experi- 
ment in the kitchen. 




85 



i^s£LV boliy clraf es — v^onti 



L > 



1111 e 



STARCHES — Starch is distributed in most plant 
parts. It is a carbohydrate with very large molecules. 
Take a look at its formula: (C 6 H I0 O s ),. At first glance 
it looks quite simple. But note that little x — it 
stands for "any number of times." A single molecule 
of starch may weigh 6.000 times as much as a single 
molecule of glucose. 

You can break this polysaccharide ("many-sugar") 
into the monosaccharide ("single-sugar") glucose by 
treating it with an acid. 

CELLULOSE is the building material of the plant 
world. It makes up the cell walls of leaves and stalks. 



A GROWING PLANT IS THE 
MOST ASTONISHING CHEM- 
ICAL FACTORY ON EARTH. 
THE GREEN SUBSTANCE IN 
LEAVES — CALLED CHLORO- 
PHYLL — WITH THE HELP OF 
SUNLIGHT IS ABLE TO COM- 
BINE WATER (TAKEN IN BY 
THE ROOTS) WITH CARBON 
DIOXIDE FROM THE AIR 
(TAKEN IN THROUGH THE 
LEAVES) TO FORM SUGAR 
FIRST AND THEN STARCH. 





wood and fibers. Cotton is 95 per cent cellulose. The 
paper on which this book is printed is specially- 
treated cellulose. So is the cellophane around your 
candy and the rayon that goes into ladies' dresses. 
For more about cellulose in natural fibers and rayon, 
see pages 102-103. 

EXPERIMENTS WITH PHOTOSYNTHESIS 

, 1 POT UP A NASTURTIUM OR GERANIUM PLANT AND 
PLACE IT IN THE DARK FOR A COUPLE OF DAYS. 
THEN FASTEN STRIPS OF BLACK PAPER ACROSS BOTH 
SIDES OF ONE OR MORE LEAVES. NOW EXPOSE THE 
GROWING PLANT TO THE SUNLIGHT FOR TWO HOURS. 




2 PICK OFF A LEAF. REMOVE BLACK PAPER STRIPS. 
DIP IN BOILING WATER FOR A MOMENT TO KILL 
THE LEAF. THEN DROP IT INTO DENATURED ALCOHOL 
IN A CUSTARD CUP. PLACE CUSTARD CUP IN A POT 
OF BOILING WATER. AS ALCOHOL GETS HOT, IT EX- 
TRACTS THE CHLOROPHYLL FROM THE LEAF. KEEP 
LEAF IN ALCOHOL UNTIL ALL CHLOROPHYLL IS OUT. 

PLACE LEAF IN IODINE TEST SOLUTION. PARTS 
EXPOSED TO SUN TURN BLUE. THIS PROVES PRES- 
ENCE OF STARCH. UNEXPOSED PARTS BECOME BROWN. 



86 



PREPARING STARCH 





TO 10 ml 1 PER CENT STARCH 
SOLUTION ADD 10 DROPS HY- 
DROCHLORIC ACID. BOIL FOR 
2 MINUTES. TEST THE RESULT 
WITH FEHLING SOLUTION. YOU 
GET RED PRECIPITATE THAT 
SHOWS PRESENCE OF GLUCOSE. 
UNTREATED STARCH SOLUTION 
DOES NOT REACT WITH THE 
FEHLING SOLUTION. 



LINE UP FIVE TEST TUBES, EACH CONTAINING 5 ml 
WATER AND 1 DROP IODINE TEST SOLUTION. IN AN- 
OTHER TEST TUBE, ADD 2 DROPS OF SALIVA (SPIT- 
TLE) TO 5 ml STARCH SOLUTION. PLACE THIS IN 
GLASS OF WARM [NOT HOT) WATER. WITH 2-MINUTE 
INTERVALS, DROP 3 DROPS SALIVA-STARCH MIXTURE 
INTO A TEST TUBE WITH IODINE SOLUTION. SHAKE. 
COLOR GETS LESS AND LESS BLUE. SALIVA DIGESTS 
THE STARCH AND TURNS IT INTO A SUGAR, MALTOSE. 




JUST A FEW OF THE 
THOUSANDS OF ITEMS 
THAT CONTAIN ETHA- 
NOL OR ARE MANUFAC- 
TURED WITH ITS HELP. 




iVllany Kinds of Alcohols 



.any 

To most people, alcohol is the strong stuff in beer, 
wine, and hard liquor. But to a chemist, this is just 
one of many alcohols. 

Alcohols may be considered hydrocarbons in which 
one or more hydrogen (H) atoms are replaced by 
hydroxy] (OH) groups. Their names are made up 
from the names of the hydrocarbons to which they 
are related by giving these an "-ol" ending. In this 
way, CH 4 , methane, becomes CH 3 OH, methanol 
(also called methyl alcohol); C 2 H 6 , ethane, becomes 
C 5 H 5 OH, ethanol (also known as ethyl or grain al- 
cohol) ; and so on. Methanol (CH 3 OH) was originally 
called wood alcohol because it was made by the de- 
structive distillation of wood. It is very poisonous 
and is therefore used to "denature" ethanol, making 
this unfit for drinking. 



Ethanol (C 2 H s OH) is produced today, to a great 
extent, in the same way in which it was made thou- 
sands of years ago, by- a process called fermentation. 
In this, the tiny plant cells of yeast are made to grow 
in the solution of a simple sugar, such as glucose 
(C 6 H,j0 6 ). In growing, the yeast cells give off a sub- 
stance called zymase. This acts as a catalyst and 
turns the glucose into ethanol and carbon dioxide: 

C 6 H,,0 6 — 2C 2 H 5 OH + 2CO, \ 
The ethanol is finally separated from the watery 
liquid by distillation. 

Glycerol (CjH 5 (OH) 3 ) is still another alcohol 
which you probably know better under the name of 
glycerin. Glycerol may be considered a product of 
propane (C 3 H 5 ) in which not one but three H atoms 
have been replaced by OH. 



THE "FAMILY TREE" OF ETHANOL— WITH SOME OF ITS CHItDREN, GRANDCHILDREN, AND GREAT-GRANDCHILDREN. 

* — SYNTHETIC RUBBER 



ETHANOL 



(GRAIN 
ALCOHOL) 




ETHYLENE 
DIETHYL ETHER 
ACETIC ACID 
IODOFORM 






ACETALDEHYDE 



STYRENE 



GLYCOL 



ACETONE 



CELLULOSE ACETATE 

ACETALDEHYDE 
CYANOHYDRIN 

ACETIC ANHYDRIDE 



PLASTICS 

OXALIC ACID 
EXPLOSIVES 



-BUTYL ALCOHOL 
CHLOROFORM 



PHOTOGRAPHIC FILM 
TEXTILE FIBERS 

PROPIONIC ACID 

VINYL ALCOHOL 
ACETANIUDE 



METHYL ALCOHOL — 
METHANOL 




/ \ 

methanol 
vapors burn 
with blue 
flame 

METHANOL CAN BE PRODUCED BY DRY DISTILLATION OF 
WOOD. FILL A TEST TUBE ONE THIRD FULL OF SLIVERS 
OF V/OOD. HEAT. LEAD VAPORS THROUGH L-SHAPED GLASS 
TUBE INTO TEST TUBE IN MIXTURE OF WATER AND ICE. 



ETHYL ALCOHOL — 
ETHANOL 




methyl salicylate 

crush an aspirin 
tablet. mix with 
Va teaspoon sodium 
bisulfate. heat, 
drop a few drops 
of methanol (or 
denatured alcohol) 
onto hot mixture, 
you get smell of 
wintergreen oil- 
methyl salicylate. 




Mk 





ETHANOL IS 
PRODUCED BY 
THE FERMENTA- 
TION OF SUGAR 






V IN A PINT BOTTLE MIX % CUP CORN SYRUP WITH 
1 CUP V/ARM WATER. ADD >/ 2 PACKAGE YEAST THAT 
HAS BEEN SOFTENED IN LUKEWARM WATER. PLACE BOT- 
TLE IN A WARM SPOT. SHORTLY THE LIQUID BEGINS 
TO BUBBLE. LEAD THE GAS INTO LIME WATER. GAS IS 
CO,. IN A FEW DAYS, GAS DEVELOPMENT SLOWS DOWN. 



2 FILTER HALF OF THE FERMENTED LIQUID INTO A 
1-PINT SCREW-TOP CAN. SET UP APPARATUS FOR 
DISTILLATION AS DESCRIBED ON PAGE 61 WITH THE 
EXCEPTION THAT HEATING IS DONE ON A WATER BATH 
MADE FROM HALF A QUART CAN WITH WATER. DISTILL 
OFF A FEW ml ETHANOL AT LOWEST POSSIBLE HEAT. 




IODOFORM FROM 
ETHANOL 

TO A SOLUTION OF 1 g 
POTASSIUM IODIDE IN 5 
ml WATER ADD IODINE 
CRYSTALS TO GET DARK 
BROWN COLOR. ADD 5 ml 
ETHANOL. ADD 10% NaOH 
SOLUTION UNTIL COLOR 
DISAPPEARS. HEAT GENTLY 
TWO MINUTES. LET COOL. 
THE YELLOW PRECIPITATE 
c? IS IODOFORM — CHIj. 




ETHYL ACETATE 
FROM ETHANOL 

IN A TEST TUBE, MIX 3 ml 
ETHANOL WITH 2 g SO- 
DIUM BISULFATE AND 3 ml 
WHITE VINEGAR. HEAT IT 
GENTLY. SNIFF CAREFUL- 
LY. THE SOUR SMELL OF 
VINEGAR HAS TURNED 
INTO THE FRUITY SMELL 
OF ETHYL ACETATE 
(CH,COOC 2 H 5 ). IT IS A 
MUCH-USED SOLVENT. 




cb 



CHLOROFORM FROM 
ETHANOL 

MIX 5 ml ETHANOL WITH 
5 ml SODIUM HYPOCHLO- 
RITE SOLUTION ("CLO- 
ROX"). HEAT MIXTURE 
GENTLY FOR A FEW MO- 
MENTS WITHOUT BOILING. 
THEN SNIFF CAREFULLY. 
YOU GET THE PECULIAR 
SWEETISH ODOR OF CHLO- 
ROFORM. THE C,H 5 OH HAS 
BEEN TURNED INTO CHCI 3 . 



89 




- J= a^}. 




ACETIC ACID IS WHAT 
MAKES VINEGAR TASTE 
SOUR. VINEGAR MEANS 
"SOUR WINE." THAT IS 
WHAT IT USED TO BE. 



TANNIC ACID, USED FOR 
TANNING, IS FOUND IN 
THE BARK OF A NUMBER 
OF TREES AND IN GALL 
APPLES ON OAK TREES. 




Oar boxy lie A.cids 

Cam you think of anything more refreshing than a 
glass of cold lemonade on a hot summer's day? Or 
anything better than cranberry sauce for adding a 
tangy taste to the Thanksgiving dinner? 

The tartness of lemonade and cranberry sauce 
comes from organic acids. 

These acids are found ready-made in nature in 
great numbers. Some of them occur as free acids 
(citric acid, tannic acid, malic acid), others as esters 
(products of acids and alcohols, such as fats and oils 
and the flavors of many fruits and the odors of many 
flowers). Still other of these organic acids are pro- 
duced by the action of bacteria (acetic acid from 
wine or cider, lactic acid when milk turns sour, bu- 
tyric acid in rancid butter). 

Some organic acids can be extracted directly from 
the plant parts in which they are found. But to get 
them in pure and concentrated form it is usually 
necessary to turn them into sodium or calcium salts 
and then free the acids from the salts with a stronger 
acid. Many of the acids which were formerly ob- 
tained from plant parts can now be made artificially 
in the laboratory. 

Organic acids have one tiling in common. They 
all contain a combination of one carbon atom, one 
oxygen atom, and one hydroxyl group (OH). This 
COOH combination, called a carboxyl group (from 
a joining-up of the words carbon and hydro.ryO> 
has given the organic acids their scientific name, car- 
boxylic acids. When these acids form salts it is the 
H in the carboxyl group that is replaced by a metal, 
as, for instance, when CH 3 COOH (acetic acid) forms 
CHjCOOXa (sodium acetate). 



MALIC ACID IS FOUND IN MANY 
UNRIPE FRUITS— GREEN APPLES, 
PLUMS, CURRANTS, AND A GREAT 
NUMBER OF OTHERS. NAME COMES 
FROM LATIN MALUS— APPLE TREE. 



OXALIC ACID ORIGI- 
NALLY CAME FROM THE 
WOOD SORREL PLANT — 
OXAL/S. NOW IT IS 
MADE ARTIFICIALLY. 




FORMIC ACID IS THE 
HIGHLY IRRITATING 
ACID THAT ANTS (FOR- 
MICA) PUMP INTO YOU 
WHEN THEY BITE YOU. 



ACETIC ACID 



YOU HAVE ALREADY MADE 
SODIUM ACETATE (ON PAGE 83) 





VINEGAR IS DILUTED ACETIC ACID. SEVERAL OF ITS 
SALTS — ACETATES — CAN BE MADE FROM VINEGAR. USE 
LIME FOR MAKING THE CALCIUM SALT — (CH,COO),Ca. 

WARM 50 ml WHITE VINEGAR IN A CUSTARD CUP. 
D CALCIUM OXIDE UNTIL NO MORE DISSOLVES. 



ADI 



(5) FILTER SOLUTION TO REMOVE UNDISSOLVED CALCI- 
UM OXIDE. FILTRATE CONTAINS CALCIUM ACETATE. 

(3/ EYAPORATE SOLUTION UNTIL ALMOST DRY. DO NOT 
OVERHEAT— IF YOU DO, THE ACETATE BREAKS UP 
INTO CALCIUM CARBONATE AND ACETONE (CHjCOCH,). 



YOU CAN AGAIN DRIVE ACETIC 
ACID OUT OF ITS CALCIUM SALT. 

MIX CALCIUM ACETATE WITH AN 
EQUAL AMOUNT OF SODIUM Bl- 
SULFATE. PLACE IN DRY TEST 
TUBE. HEAT GENTLY. YOU GET 
SHARP ODOR OF ACETIC ACID. 
MOISTENED BLUE LITMUS PAPER 
AT MOUTH OF TUBE TURNS RED. 



SALICYLIC ACID 





1 SHAKE UP 1 g SALICYLIC 
ACID WITH 10 ml WATER. IT 
DOES NOT GO INTO SOLUTION. 

2 ADD 10 PER CENT NaOH 
SOLUTION BY THE DROP UN- 
TIL ALL SALICYLIC ACID IS 
DISSOLVED. YOU NOW HAVE A 
SODIUM SALICYLATE SOLUTION. 



3 WITH IRON SULFATE, SODI- 
UM SALICYLATE GIVES RED- 
BROWN FERROUS SALICYLATE. 

4 A FERRIC SALT GIVES WINE- 
RED FERRIC SALICYLATE. 

5 COPPER SULFATE GIVES THE 
GREEN COPPER SALICYLATE. 



TANNIC ACID 

TANNIC ACID IS 
FOUND IN TEA. 




CjJ BOIL y, TEASPOON TEA IN 
50 ml WATER. THEN LET IT 
STAND TO STEEP AND COOL. 
POUR OFF THE CLEAR LIQUID. 

2 DISSOLVE A CRYSTAL OF 
IRON SULFATE IN 5 ml WA- 
TER AND ADD TO THE TEA. 
YOU WILL GET A BLACK PRE- 
CIPITATE OF IRON TANNATE. 



PHENOL FROM 

SALICYLIC 

ACID 





IN A DRY TEST TUBE, MIX 
A SMALL AMOUNT OF SALI- 
CYLIC ACID WITH AN EQUAL 
AMOUNT OF CALCIUM OXIDE. 
HEAT GENTLY. REMOVE TUBE 
FROM HEAT. SNIFF. YOU GET 
THE ODOR OF PHENOL — ALSO 
KNOWN AS CARBOLIC ACID. 



91 




BEEF 



MOST FATS PRODUCED 
BY PLANTS ARE LIQ- 
UID OILS FOUND IN 
FRUITS AND SEEDS. 




FATS FROM ANIMALS ARE 
MOST COMMONLY SOLID AT 
USUAL ROOM TEMPERATURE. 



butter 



OF 



iiersy 



PIGS 



Some of the food you eat is used for your growth, 
some of it for giving you the energy to do all the 
things you want to do. Much of this energy comes 
from carbohydrates (sugars and starches). The rest 
you get from fats — the most concentrated energy- 
foods available. 

All fats are esters, that is, combinations of fatty- 
acids with the alcohol, glycerol (glycerin). Some fats 
(butter, lard) are solid at usual room temperature, 
others are liquid (olive oil, corn oil). But when heat- 
ed, the solid fats melt, and, when cooled, the liquid 
fats turn solid. 

Liquid fats can be turned completely into solid 
fats by a process called hydrogenation. In this, more 
hydrogen atoms are added to their molecules with 
the help of a catalyst. That is how vegetable short- 
enings and margarine are made. The liquid olein in 
peanut, cottonseed, and soybean oils is made to pick 
up hydrogen and become a solid fat known as stearin : 
(C„H„COO) i C 1 H 5 + 3H, — (C„ H 35 COO) 3 C 3 H s 
(olein) (stearin) 

Fats and oils are used for many other things in 
addition to their use as food. Soap and candles are 
made from fats. So are paints and varnishes, printers' - - 
inks and some of the detergents. 







CODFISH 







T 1 - ^9mtS&'^Z ~ " 






EXTRACTING 
FAT 




[ .%> SHAVE A SMALL SQUARE OF BAKER'S CHOCO- 
LATE OR BITTER CHOCOLATE INTO FINE BITS. 

© IN A CUSTARD CUP, FOUR CARBON TETRACHLO- 
RIDE OVER THE CUT-UP CHOCOLATE AND STIR. 



RENDERING 




3 ' FILTER CHOCOLATE-TETRACHLO- 
RIDE MIXTURE. LET FILTRATE STAND 
UNTIL CARBON TETRACHLORIDE HAS 
EVAPORATED AND YELLOW-WHITE 
COCOA BUTTER IS LEFT. 



Be careful not 



real 




'•RENDERING" IS THE MOST COM- 
MON METHOD OF EXTRACTING FAT. 



^ CUT UP A SMALL AMOUNT OF SUET— THE FAT 
FROM A PIECE OF BEEF. DROP IT INTO HOT 
WATER. BOIL WATER FOR TEN MINUTES OR MORE. 

Q REMOVE THE RENDERED-OUT SUET. PLACE CUS- 
TARD CUP IN REFRIGERATOR. AFTER COOLING YOU 
CAN LIFT OFF THE FAT AS A SOLID DISK. 



TEST FOR GLYCEROL 
(GLYCERIN) 

IN A DRY TEST TUBE ADD '/, TEA- 
SPOON SODIUM BISULFATE TO 1 ml 
VEGETABLE OIL AND HEAT GENTLY. 
WAFT THE IRRITATING ODOR TO- 
WARD YOU AND SNIFF CAUTIOUSLY. 
THE SMELL IS FROM ACROLEIN 
WHICH IS PRODUCED BY BREAKING 
DOWN THE GLYCERIN IN THE FAT. 






1 CRUSH A COUPLE OF PEANUTS. DROP THEM IN A TEST 
TUBE. COVER THEM WITH CARBON TETRACHLORIDE AND 
LET STAND ABOUT 5 MINUTES. POUR A FEW DROPS ON A 
PIECE OF PAPER. LET CARBON TETRACHLORIDE EVAPORATE. 

2 LOOK AT THE PAPER AGAINST THE LIGHT. THE ALMOST 
TRANSPARENT "GREASE SPOT" IS A TEST FOR FAT. 



FATTY 
ACIDS 



THE NaHS0 4 SETS THE 
GLYCEROL FREE, THEN 
IMMEDIATELY DESTROYS 
IT. GLYCEROL LOOSES 
WATER AND TURNS INTO 
ILL-SMELLING ACROLEIN: 
C 3 H s (OH) 3 ^. 
C.K.O + SHjO 



93 




*zm 



TEASPOON SOAP 
POWDER OR FLAKES IN 50 ml WARM 
WATER. ADD 10 ml HYDROCHLORIC 
ACID. YOU WILL GET LUMPS OF 
THE FATTY ACIDS OF WHICH SOAP 
IS THE SODIUM SALT— MOSTLY 
STEARIC AND PALMITIC ACIDS. 
STEARIC ACID IS ADDED TO PAR- 
AFFIN IN THE MAKING OF CANDLES. 







IN THE OLD-FASHIONED SOAP KETTLE, ONLY A FEW 
GALLONS OF SOAP COULD BE MADE AT ONE TIME. 



ooap amd. ooap JxlLalkiiig 

Wheotver your haxds get dirty, it is an easy matter to get them clean. 
All you need is water and plenty of CHjCHjCHjCH-CHjCHjCHjCHjCH, 
CHjCHjCHsCHsCH.CHjCHoCH^OONa — C 17 H 35 COONa for short, the 
sodium salt of stearic acid, a substance more generally known as soap. 

Soap has been used for cleaning for thousands of years. Xo one knows who 
invented it — but the method for making it was passed down from father 
to son, from mother to daughter. The early soap makers first had to burn 
wood to get potash (K 2 C0 3 — see page, 59) or dried seaweed to get soda ash 
(Na|,CO|).This was treated with lime to make potassium or sodium hydrox- 
ide (KOH or NaOH — see page 45), and this, in turn, was boiled with fat 
to make soap. Very much the same method is used today — except that the 
boiling is done in tremendous soap pans under steam pressure. 



IN MODERN SOAP PANS, 
SEVERAL STORIES HIGH, UP 
TO 1 00 TONS OF FAT CAN 
BE TURNED INTO SOAP. 





STRONG SOAP BUBBLES RESULT 
WHEN YOU ADD GLYCERIN TO 
THE SOAP SOLUTION. HERE IS 
A RECIPE: 5 g SOAP, 100 ml 
WATER, AND 10 ml GLYCERIN. 



8 









THIS IS THE WAY SCIENTISTS BELIEVE THAT SOAP ACTS: ONE 
END OF THE SOAP MOLECULE IS SOLUBLE IN WATER, THE OTHER 
END IN OIL. WHEN OIL IS SHAKEN UP IN SOAPY WATER, THE 
OIL DROPS ARE SURROUNDED BY THE SOAP MOLECULES DIPPING 
THE OIL-DISSOLVING ENDS INTO THE OIL. THE WATER-SOLUBLE 
ENDS HOLD THE OIL DROPLETS SUSPENDED. 



94 



MAKING SOAP 




3 DISSOLVE 100 g TABLE 
SALT IN 300 ml WATER. POUR 
THE HOT SOAP MIXTURE INTO 
THIS SOLUTION. THE SOAP 
V/ILL "SALT OUT" IN THICK, 
CHEESE-LIKE CURDS. 



' 1, : MELT 10 g SHORTENING ("CRISCO" OR SIMILAR 
PRODUCT) IN A CUSTARD CUP ON THE WATER BATH. 

(2) DISSOLVE 5 g SODIUM HYDROXIDE (NaOH) IN 15 
mf WATER. ADD 15 ml DENATURED ALCOHOL (TO 
SPEED UP THE ACTION). POUR THIS SOLUTION INTO 
THE MELTED SHORTENING WHILE STIRRING. CONTINUE 
HEATING AND STIRRING UNTIL A SMALL SAMPLE DIS- 
SOLVES COMPLETELY IN >/ 2 TEST TUBE WATER. THE 
SOAP MAKING (SAPONIZATION) IS THEN COMPLETED. 



/^ttK 



TESTING SOAP 
AND DETERGENTS 

DISSOLVE 1 g OF YOUR HOME- 
MADE SOAP IN 50 ml LUKE- 
WARM WATER. ALSO MAKE 
SOLUTIONS IN 50 ml WATER 
OF 1 g TOILET SOAP, 1 g SOAP 
FLAKES, 1 g SOAP POWDER, 
1 g POWDERED DETERGENT, 
AND 1 ml LIQUID DETERGENT. 



POUR 10 ml OF THE SOAP AND DETER- 
GENT SOLUTIONS INTO SEPARATE TEST TUBES. 
TEST EACH SOLUTION FOR ACID AND BASE 
WITH LITMUS PAPER AND PHENOLPHTHALEIN. 

! SHAKE 5 DROPS OF OIL INTO EACH SOLU- 
TION. NOTE THE DIFFERENCE IN THE WAY 
THE SOLUTIONS MAKE EMULSION WITH OIL. 

1 AGAIN, POUR 10 ml OF EACH SOLUTION 
INTO SEPARATE TEST TUBES. ADD 5 ml LIME- 
WATER TO EACH. SHAKE AND NOTICE THE 
DIFFERENCE IN THE AMOUNT OF FOAM MADE 
BY EACH SOLUTION IN THIS "HARD" WATER. 




(4) TIE A PIECE OF CHEESE CLOTH OVER THE TOP 
OF A JAR. POUR THE SALT SOLUTION WITH THE 
SOAP CURDS INTO CHEESE CLOTH AND LET SALT SO- 
LUTION DRAIN OFF. WASH THE SOAP BY POURING 
TWO TEST TUBES OF ICE-COLD WATER THROUGH IT 
TO REMOVE MOST OF THE SALT THAT'S STILL ON IT. 

(S) FINALLY, SQUEEZE OUT THE V/ATER AND SPREAD 
OUT THE CHEESE CLOTH TO LET THE SOAP DRY. 



A 

/ 






i 








2 






3 










F 


























XU 



cheese 




Irggfemafi — one B@tay^Bm!<dliiLiLg Foods 



At almost every meal, we look forward especially 
to the proteins: ham and eggs for breakfast, ham- 
burgers or frankfurters for lunch, steak or chicken 
for dinner. We drink milk mostly for the sake of its 
proteins. Even many of our desserts are protein prod- 
ucts — from ice cream to Jell-O. 

While most other foodstuffs, such as carbohydrates 
and fats, consist of carbon, hydrogen, and oxygen, 



the proteins also contain nitrogen and, for the most 
part, sulfur. Their molecules are "giants" compared 
with the molecules of other chemical compounds. 
One of them, albumin in egg, has this estimated 
formula: C 696 H n j502ooN 190 S 15 . 

Not all proteins are edible. You would hardly think 
of eating hair and nails, furs and feathers — yet 
these are all proteins. (CONTINUED ON PAGE 99) 



PROTEIN IN EGG 




SHAKE 5 ml EGG WHITE WITH 
5 ml WATER. ADD 5 ml DENA- 
TURED ALCOHOL. THE ALCOHOL 
CAUSES THE ALBUMIN TO COAG- 
ULATE OUT IN WHITE FLECKS. 



CRACK AN EGG. SEPARATE WHITE FROM YOLK BY 
LETTING WHITE FLOW INTO A CUP WHILE RETAIN- 
ING YOLK IN EGG SHELL. BEAT WHITE WITH FORK. 





vesfr 



SHAKE 5 ml BEATEN EGG WHITE WITH 
5 ml WATER. BRING TO A BOIL. THE 
HEAT CAUSES THE ALBUMIN TO COAG- 
ULATE. IT HAS BEEN "DENATURIZED." 
IT CAN NOT AGAIN BE MADE SOLUBLE. 




FILL CUSTARD CUP HALF 
FULL OF WATER. BRING TO 
A BOIL. POUR IN THE EGG 
WHITE THAT IS LEFT. IT 
COAGULATES INTO A FIRM 
WHITE MASS. THIS METHOD 
IS USED IN COOKING. IT 
IS CALLED "POACHING." 



96 



THE ITEMS ON THE 
TOP OF THESE TWO 
PAGES ALL CONTAIN 
PROTEINS. 




WHAT DOES ALBUMIN CONSIST OF? 

-< 




DROP A SMALL PIECE OF COAGULATED EGG WHITE 
INTO A TEST TUBE. COVER IT WITH 5 ml 10% NaOH 
SOLUTION. HEAT. WHITE GOES IN SOLUTION. 

1 POUR A FEW DROPS OF THE EGG WHITE SOLU- 
TION ONTO A BRIGHT SILVER COIN. IN A FEW MINUTES 
SILVER COIN TURNS BROWNISH-BLACK FROM SILVER 
SULFIDE, PROVING THAT ALBUMIN CONTAINS SULFUR. 



TEST FOR SOLID 
WHITE PROTEIN 




1 IN TEST TUBE, DIS- 
SOLVE '/, TEASPOON 
SODIUM BISULFATE IN 
5 ml WATER. ADD '/ 4 
TEASPOON POTASSIUM 
NITRATE. DROP IN SMALL 
PIECE OF COAGULATED 
EGG WHITE. HEAT. 
NaHS0 4 AND KNO, 
FORM HNO, — NITRIC 
ACID. THIS COLORS THE 
ALBUMIN YELLOW. 

2 ADD HOUSEHOLD 
AMMONIA. THE YEL- 

TEST CHEESE, WOOL, CHICKEN, LOW ALBUMIN TURNS 
LIMA BEANS THE SAME WAY. BRIGHT ORANGE. 



'• 1 ' PLACE A SMALL PIECE OF 
COAGULATED EGG WHITE 
ON A PIECE OF TIN. HEAT. 
VAPORS SMELL OF AMMO- 
NIA AND TURN WETTED RED 
LITMUS PAPER BLUE. AMMO- 
NIA IS NH,. ALBUMIN MUST 
CONTAIN N AND H. 



ALBUMIN IS FOUND 
IN EGGS, BLOOD, 
MILK, AND GRAIN. 





2 CONTINUE HEAT- 
ING. IN THE END, 
CARBON REMAINS. 
ALBUMIN THEREFORE 
CONTAINS CARBON. 
IT ALSO CONTAINS 
OXYGEN. 



WHAT DOES EGG YOLK CONTAIN? 




Be careful not to breathe fumes. 

1 SHAKE 5 ml OF THE YOLK WITH 5 ml CARBON TET- 
RACHLORIDE TO FIND OUT IF IT CONTAINS FAT. 

2 POUR A LITTLE OUT ON PAPER. LET CARBON TET- 
RACHLORIDE EVAPORATE. GREASE SPOT REMAINS. 

3 HEAT THE MIXTURE. YOU GET A WHITE COAGULA- 
TION. YOLK AND WHITE BOTH CONTAIN ALBUMIN. 



97 



PROTEIN IN MILK 

MILK !S AN IMPORTANT SOURCE 
OF PROTEIN. THE PROTEIN IN 
MILK IS CALLED CASEIN. CHEESE 
IS SPECIALLY TREATED CASEIN. 






tf* 



s* 



1 ADD ONE TEST TUBE FULL OF 
WHITE VINEGAR TO THE WARM 
SKIM MILK. THE CASEIN SEPA- 
RATES IN HEAVY, WHITE CURDS. 



(OR MIXTURE OF 8 TEA- 
SPOONS SKIM MILK POWDER 
AND '/ 2 CUP WATER) INTO 
A CUSTARD CUP. HEAT 
GENTLY UNTIL IT FEELS JUST 
SLIGHTLY WARM WHEN YOU 
TEST IT WITH A FINGER. 




'# ./FOLD CHEESE CLOTH UP AROUND 
THE CASEIN. DIP THE BAG IN WA- 
TER AND SQUEEZE SEVERAL TIMES 
TO WASH OUT WHEY AND VINEGAR. 

(5) SQUEEZE THE CASEIN ALMOST 
DRY. SPREAD OUT THE CHEESE CLOTH 
TO LET THE CASEIN DRY. 



m 

I TIE A PIECE OF CHEESE ^ 
CLOTH OVER A JAR. POUR 
THE CURDLED MILK INTO THE 
CHEESE CLOTH. LET LIQUID 
(WHEY MIXED WITH VINEGAR) 
RUN OUT. KEEP THE LIQUID. 



WHAT ELSE IS IN MILK? 

1 POUR THE VINEGAR-MIXED WHEY INTO A 
"CUSTARD CUP AND BRING IT TO A BOIL. YOU 
WILL SEE TINY WHITE FLECKS. THESE ARE 
ALBUMIN COAGULATED OUT BY THE HEAT. 

(2) FILTER THE WHEY. TEST THE FILTRATE 
WITH FEHLING SOLUTION (SEE PAGE 85). 
MILK SUGAR GIVES RED Cu,0 PRECIPITATE. 




MAKING CASEIN GLUE 

SOFTEN 4 g CASEIN WITH 4 ml WATER. 
SHAKE UP 1 g CALCIUM OXIDE IN 4 m! 
WATER. POUR THE CALCIUM OXIDE MIX- 
TURE INTO THE CASEIN WHILE STIRRING. 
THE RESULTING SMOOTH PASTE IS AN EX- 
CELLENT GLUE FOR PAPER AND FOR WOOD. 



I 





98 



GELATIN IS A PROTEIN 



GELATIN IS MADE FROM 
ANIMAL BONES AND HIDES. 




REMOVE THIGH BONE 
FROM AN UNCOOKED 
CHICKEN LEG. SCRAPE IT 
CLEAN OF MEAT. DROP IT 
IN A TEST TUBE. COVER 
WITH 3 ml HYDROCHLO- 
RIC ACID IN 12 ml WATER. 
LET STAND FOR 3 DAYS. 



2 THE DILUTED HYDROCHLORIC 
ACID DISSOLVES THE CALCIUM 
SALTS IN THE BONE, LEAVING 
A FLEXIBLE SUBSTANCE CALLED 
OSSEIN. WASH OFF THE ACID. 
EXTRACT THE GELATIN IN THE 
OSSEIN BY BOILING IN WATER. 




'3 . FILTER THE SOLUTION. ON COOLING, IT BECOMES 
JELLY-LIKE. IT HAS TURNED FROM "SOL" TO "GEL." 



JProieims — Lontirmett 

^ou are certain to be familiar with three common, 
pure proteins: albumin in eggs, casein in mill.- , and 
gelatin. 

ALBUMIN — Egg white contains around 13 per 
cent albumin — from Latin albus, white. 

When you shake up egg white with water, you 
get what looks Like an almost clear solution. But 
this is not a "true" solution such as you get when 
you dissolve salt or sugar — it is another kind of 
'"solution" called a "colloidal dispersion." For more 
about colloidal dispersions, see pages 100-101. 

As long as egg white is kept cool, it stays trans- 
parent and almost liquid. But what happens when 
you heat it? "V ou know from frying or boiling an egg: 
It hardens — coagulates — into a solid white mass 
which you can not again "dissolve" in water. The 
chemist's term for this change is "denaturation" — 
the egg white has changed its nature. 

CASEIN — Casein is another protein that goes into 
your diet. Some of the casein you drink (milk), some 
of it you eat (ice cream and cheese). 

In cheese making, the casein is separated from the 
liquid part of the milk — the whey. It is then pressed 
and stored until ripe. The flavors of cheeses are caus- 
ed mostly by esters created during the ripening. 



GELATIN — Gelatin is a protein made from animal 
skins and bones, horns and hooves. 

Gelatin behaves in a peculiar manner with water. 
In cold water it merely swells, but in hot water it 
"dissolves" readily, forming a colloidal dispersion. 
As long as you keep this dispersion warm, it remains 
in a liquid form that is called a "sol." When cooled, 
it turns into a jelly-like form called a "gel." 



TEST FOR LIQUID PROTEINS 



MIX 5 ml OF LIQUID TO 
BE TESTED WITH 5 ml 
0% SOLUTION OF 
NaOH. ADD TWO 
DROPS OF A 2% SO- 
LUTION OF COPPER 
SULFATE [1 g IN 50 ml 
WATER). LIQUID WILL 
TURN REDDISH-VIOLET. 




99 




BLOOD 

solid in liquid 



IN 1 862, A SCOTTISH CHEMIST, 
THOMAS GRAHAM, PRESENTED 
HIS IDEAS ABOUT COLLOIDS. 





v^oMoiclal JUispersions 

Would you walk up to a soda fountain and order 
"a triple, chocolate-flavored colloidal dispersion"? 
No? Yet that's what you do when you ask for a 
chocolate sundae. Ice cream is a colloidal dispersion 
of solids in a liquid; so is chocolate syrup. Whipped 
cream is a colloidal dispersion of air in a liquid. 

It was a Scot, Thomas Graham, who explained 
colloids, in 1862. He noticed that some solutions 
passed through parchment paper, others didn't. He 
discovered that most of those that filtered through 
wore of chemicals that formed crystals — he called 
them "crystalloids." The others he called "colloids" 
— from Greek kolbdes, glue-like. 

When a colloid is mixed with water, it does not 
form a solution but a dispersion. In a solution, the 
molecules of the dissolved chemical are too small to 
be seen even with the strongest microscope. In a col- 
loidal dispersion, the much larger particles can be 
seen in an ultra-microscope — and you can sec them 
as a light effect when you pass a light beam through 
the dispersion. 

Colloidal dispersions can be formed by gases, liq- 
uids, and solids. Eight combinations are possible: 






^H 



v * 



^ 




fog . !| ii. 

liquid in gas 'I'. 



MUDDY WATER 

solid in liquid 



■- X 



100 




LIGHT TE 



THE PARTICLES OF A 
COLLOIDAL DISPERSION 
REFLECT LIGHT AND 
MAKE THE PATH OF A 
LIGHT BEAM VISIBLE. 



2 LIGHT BEAM IS VISIBLE AS IT 
PASSES THROUGH A COLLOIDAL 
DISPERSION (SUCH AS OF SULFUR). 



c 






f 


f 




\ 




2 







THIS "TYNDALL EFFECT" GOT 
ITS NAME FROM AN ENGLISH 
SCIENTIST, JOHN TYNDALL. 




gases in liquids and in solids; liquids in gases, in 
olher liquids, and in solids; solids in gases, in liquids, 
and in other solids. The illustrations show some of 
these possibilities — you can think of many others. 
The colloidal state is important to life. It is the 
way in which we get most of our food, the way we 
digest it, and the way the blood carries nourishment 
throughout our bodies. 



IN PEPTIZATION, LARGE PARTICLES ARE BROKEN DOWN 
INTO SMALLER PARTICLES OF COLLOIDAL SIZE. 



1 . SHAKE UP 1 g STARCH WITH 100 ml 
COLD WATER. IF LEFT UNDISTURBED, 
STARCH QUICKLY SETTLES TO BOTTOM. 

POUR THE MIXTURE OF STARCH AND 
WATER INTO A CUSTARD CUP. BRING 
TO A BOIL, THEN COOL. STARCH HAS 
NOW FORMED A COLLOIDAL DISPERSION. 




IN EMULS1FICATION, ONE LIQUID IS DISPERSED IN AN- 
OTHER. EMULSIONS CAN BE TEMPORARY OR PERMANENT. 

1 SHAKE 5 ml KEROSENE AND 5 ml WATER TOGETHER 
IN A TEST TUBE. LET STAND FOR A SHORT TIME. LIQUIDS 
SEPARATE. THE EMULSION WAS TEMPORARY. 

2 SHAKE 5 ml KEROSENE WITH SOLUTION OF '/ 2 g SOAP 
IN 5 ml WARM WATER. THEN LET STAND. LIQUIDS DO 
NOT SEPARATE. THIS IS A PERMANENT EMULSION. 




IN COAGULATION, MANY MOLECULES OF A SUBSTANCE 
JOIN TOGETHER INTO PARTICLES OF COLLOIDAL SIZE. 

1 SHAKE 1 g FLOWERS OF SULFUR WITH 10 ml DENA- 
TURED ALCOHOL. A SMALL AMOUNT OF SULFUR GOES 
IN SOLUTION. FILTER OUT THE UNDISSOLVED SULFUR. 

2 POUR THE ALCOHOLIC SOLUTION OF SULFUR INTO 
A LARGE AMOUNT OF WATER. YOU WILL SEE A WHITE 
CLOUD OF FINELY DISPERSED COLLOIDAL SULFUR. 




101 



VEGETABLE FIBERS COME FROM 
PLANTS: COTTON, FLAX (LINEN). 




WOOL AND SILK (FROM SILK 
WORMS) ARE ANIMAL FIBERS. 



ARTIFICIAL FIBERS ARE VERY POP- 
ULAR: NYLON, DACRON, ORLON. 



JNafural and Artificial Fib 



It would be tough to get along without fibers in 
the modern world. Fibers are spun into thread, and 
the thread is made into cloth for clothing and bed- 
sheets, curtains and towels, and many other things 
around the house. Fibers also go into such articles 
as string and rope, rugs and auto tires. Some of these 
fibers come from the plant and animal worlds, others 



BURNING TEST FOR FIBERS 



CUT HALF-INCH STRIPS 
OF DIFFERENT FABRICS. 
IGNITE EACH STRIP IN 
TURN. NOTICE HOW FAB- 
RIC BURNS, THE SMELL, 
AND ASH LEFT BEHIND. 



ers 

are manufactured synthetically with coal or petro- 
leum for their starting point. 

Fibers belong in different groups of chemical com- 
pounds. Animal fibers are proteins; vegetable fibers 
are cellulose. Artificial fibers such as nylon, Orion 
and Dacron are very complex chemical compounds 
and have enormously long molecules. 




X>g>9 / 






KIND 


FLAME 


SMELL 


ASH 


1 


COTTON 


Rapid, yellow flame 


Like burning paper 


Small, fine, gray 


2 


LINEN 


Fairly fast, yellow flame 


Like cotton 


Like cotton 


3 


WOOL 


Slow, sizzling flame 


Like burning hair 


Hollow, black bead, 
easy to crush 


4 


SILK 


Small, slow flame 


Like wool 


Shiny, round bead, 
easy to crush 


5 


NYLON 


Melts; no flame 


Like celery 


Melts to black bead, 
hard to crush 


6 


ORLON 


Melts and burns 


Like broiled fish 


Black bead. 


7 


VISCOSE 
RAYON 


Rapid, yellow flame 


Like cotton 


hard to crush 
like cotton 


8 


CELLULOSE 
ACETATE 


Rapid flame with small 
sparks; melts 


Like vinegar 


Black bead, 
hard to crush 



102 



CHEMICAL TESTS FOR FIBERS 




C.l) POUR 5 ml 10% NaOH 
SOLUTION INTO EACH OF 
SIX TEST TUBES AND DROP 
IN STRIPS OF SIX KINDS 
OF CLOTH. MARK EACH 
TEST TUBE SO YOU KNOW 
WHAT IS IN EACH. 

2 PLACE TEST TUBES IN 
A CAN OF HOT WATER. 
BOIL FOR TEN MINUTES. 

S) PLACE TEST TUBES IN 
STAND. NOTE RESULT. 
WOOL AND SILK HAVE DIS- 
SOLVED, THE OTHERS NOT. 



' 



£_ 



m 



Q 



m 



£1 



a 



8 



/ 



\ 




TRY SAME EXPERIMENT 
WITH STRONG HCI. 
SILK AND RAYON DIS- 
SOLVE. BUT THE WOOL 
DOES NOT. 



MAKING RAYON 



RAYON IS MADE BY 
"DIGESTING" CELLU- 
LOSE IN CUPRAMMO- 
NIUM AND THEN SET- 
TING IT FREE AGAIN. 



1. TO MAKE CUPRAMMONIUM SOLUTION, FIRST DIS- 
SOLVE 10 g COPPER SULFATE IN 100 ml WATER IN A PINT 
JAR. ADD 10% NaOH SOLUTION UNTIL NO MORE LIGHT- 
BLUE CUPRIC HYDROXIDE FORAAS. LET STAND. POUR WA- 
TER OFF PRECIPITATE. RE-FILL THE JAR WITH WATER. 
AGAIN LET STAND. AGAIN POUR WATER OFF PRECIPITATE. 
REPEAT THIS WASHING PROCESS HALF A DOZEN TIMES. 




^2.,' AFTER LAST WASHING, 
POUR OFF WATER. POUR 
WET CUPRIC HYDROXIDE 
INTO A FILTER. WASH SOME 
MORE. THEN LET IT DRIP. 



MAKE APPARATUS AS SHOWN 
BELOW, WITH GLASS TUBE 
ENDING IN FINE JET TIP. POUR 
PAPER SOLUTION INTO BOT- 
TLE. 




(g) SCRAPE THE MOIST CUPRIC HY- 
DROXIDE INTO A GLASS. ADD STRONG 
AMMONIA (27%,, FROM DRUG STORE) 
BY THE DROP UNTIL ALL Cu(OH) 2 HAS 
DISSOLVED AND HAS BECOME DEEP- 
BLUE CuINHjI^OH),. THIS SOLUTION 
IS CALLED "SCHWEITZER'S REAGENT." 



^ TEAR UP 3 TO 4 
PIECES OF FILTER 
PAPER. STIR THEM 
INTO THE BLUE LIQ- 
UID. THEY WILL GO 
INTO SOLUTION. 



4 








V^SJ PLACE THE JET TIP JUST 
BELOW THE SURFACE OF A 
MIXTURE OF 10 ml HYDRO- 
CHLORIC ACID AND 500 ml 
WATER. BLOW. AS BLUE LIQUID STREAMS OUT 
INTO THE DILUTED ACID, IT TURNS INTO WHITISH 
STRAND OF RAYON THAT SETTLES ON BOTTOM. 



103 



THE MAKING OF A TYPICAL 

THERMOSETTING PLASTIC 

PHENOLICS 




formaldehyde phenol 




phenolic resins 




About fifty tears ago, Dr. Leo H. Baekeland. a 
Belgian-born American chemist, mixed phenol and 
formaldehyde together during an experiment. Other 
chemists had done this before Baekeland and had 
wondered how to get the messy goo that resulted 
out of their test tubes. But Baekeland had another 
approach. He asked himself, "What is it good for?" 
He decided to find out. The result was Bakelite — 
the first successful, modern plastic. 

During the year 1910, Baekeland produced less than 
25 barrels of his "phenolic" plastic in a barn in Yon- 
kers, N. Y. Nowadays, fifty years later, close to 
500 million pounds are produced yearly. During 
those same fifty years, more than a dozen other types 
of plastics were invented. 

Today, plastics seem to be everywhere. You find 
them in your home in flooring and wall coverings, 
in table tops and chair upholstery, in TV cabinets 
and telephones, in toys and games, in rigid containers 
and in squeeze bottles. Much of your food comes to 
you protected by some kind of plastic. They are used 
in planes and trains and cars. A plastic puts the 
"safety" into safety glass. Other plastics are used 
for long-wearing engine parts and for electrical in- 
sulation. 



104 



HEAT TIP OF GLASS ROD 
SLOWLY IN FLAME OF AL- 
COHOL BURNER. PRESS 
HOT TIP AGAINST PLAS- 
TIC. IT MAKES A DENT 
IN THERMOPLASTIC, NOT 
IN THE THERMOSETTING. 



BURNING 
TEST 





HOLD SMALL 
PIECE OF A 
PLASTIC IN 
FLAME. NOTE 
HOW IT BURNS. 



MOST THERMOSETTING PLAS- 
TICS GIVE OFF STRONG ODOR 
BUT DO NOT BURN. MOST 
THERMOPLASTICS BURN BUT 
SOME OF THEM STOP BURNING 
WHEN REMOVED FROM FLAME. 



Plastics are made from a few simple raw materials 
— some just from water, air, and coal, others with 
the help of petroleum or natural gas, limestone and 
salt. The plasties chemist breaks down the compara- 
tively simple molecules of these materials, then 
builds them up anew into very complex molecules. 

Plastics may be divided into two main groups ac- 
cording to their special properties. One group con- 
sists of the thermosetting plastics. These can be 
molded by heat and pressure, but can not be re- 
melted and remolded. They are along the lines of egg 
white which, once set by heat, stays set. The pheno- 
lics and ureas are important thermosetting plastics. 

The other group contains the thermoplastics. 
These are soft when heated, hard when cooled, but 
can be softened and hardened repeatedly. You can 
compare them to sulfur and candle wax. The poly- 
ethylenes, polystyrenes, vinyls, and acrylics are in 
the thermoplastics "family." 



HEAT SHAPING. THERMOPLASTICS BECOME SOFT 
WHEN HEATED. YOU CAN THEN SHAPE THEM AT WILL. 



BRING A POT OF WATER TO A BOIL. DROP IN AN 
OLD VINYL RECORD. WHEN SOFT, SHAPE IT WITH 
TWO LONG STICKS. IT BECOMES HARD AGAIN WHEN 
IT IS REMOVED FROM THE HOT WATER AND COOLED. 



THE MAKING OF A TYPICAL 

THERMOPLASTIC 

VINYL 





natural gas coke limestone 




calcium carbide 



chlorine 




105 




CHEMISTRY TAKES ON A GREATER IM- 
PORTANCE WHEN YOU NOT ONLY PER- 
FORM AN EXPERIMENT BUT ALSO WORK 
OUT THE EQUATION OF THE REACTION. 




Working out Onemical JKcpiatioiis 



Y ov have done a great number of experiments by 
now. \ on have worked with gases, liquids, and solids. 
You have precipitated and decanted, filtered and 
distilled. As you think back over the experiments you 
will discover that they fall into four main groups of 
chemical reactions. 

The simplest of these reactions is the DIRECT 
COMBINATION. In this, two or more substances 
combine to form a single more complex substance, 
as when iron and sulfur form iron sulfide: 



In a DOUBLE DISPLACEMENT, the two com- 
pounds change partners with each other. Think of 
the time when you precipitated silver chloride from 
solutions of salt and silver nitrate: 



FeS 



Fe +S + 

or when quicklime (calcium oxide) reacts with water 
to make slaked lime (calcium hydroxide) : 

C aO + H»Q j - Ca(OH) 2 

DECOMPOSITION is the opposite of chemical 
combination. In this, a substance is broken down 
into simpler substances. This was the case when you 
separated the two elements found in water: 

Hj O iHj. O — 2H, ! + O, | 

or when you made oxygen from hydrogen peroxide: 

H.O : H. O, — 2H,0 + O, | 

In a SINGLE DISPLACEMENT, one element 
takes the place of another in a compound, as when 
you made hydrogen from zinc and hydrochloric acid: 

H +BaH a — h, f + Zna, 

or when you set copper free by dropping a nail in a 
solution of copper sulfate: 

- Cu J + FeSO, 



CI + Ag NOJ — AgCl ; + NaNO, 
or when you mixed Epsom salt and washing soda: 
Mg SO, + Na,(j |— MgCO, J + Na,SO, 

In studying the chemical shorthand above, you 
notice that, in every instance, there is an equal num- 
ber of atoms of each element on either side of the 
arrow that indicates that a reaction takes place. Be- 
cause of this equal arrangement, these chemical de- 
scriptions are called equations. 

Many of these equations are scattered throughout 
this book. Many more are found in advanced chem- 
istry textbooks. But very often, a chemist has to 
work out an equation from scratch. 

Let's say you want to figure out the equation for 
dissolving aluminum foil in hydrochloric acid. You 
write out a trial equation : 

Al + HC1 — A1C1 + H | 

But is A1C1 correct? Look at the valence chart on 
page 75. Aluminum has three valence bonds, chlo- 
rine only one. One Al atom therefore takes on three 
CI atoms, and aluminum chloride must be A1C1 S . H 
isn't right, either. Hydrogen exists in the free state 
only in molecules containing two atoms (H 2 ). So you 
change the equation to this: 

Al + HO — A1C1, + Hj { 



106 



MEASURE OUT AIL CHEMICALS COR- 
RECTLY AND FOLLOW INSTRUCTIONS 
CAREFULLY. MAKE NOTES AS YOU GO 
ALONG AND WRITE DOWN RESULT 
WHEN EXPERIMENT IS COMPLETED. 




Now you need an amount of HC1 that will give 
you CI by the 3's and H by the 2's. 6HC1 will do this. 
So you write in 6HC1 and change the rest until the 
equation balances: 

2.41 + 6HC1 — 2A1CI, + 3H, \ 

Equations tell you what happens — but they tell 
far more than that. 

Take the simple equation: 

Fe + S — ■ FeS 



APPROXIMATE ATOMIC WEIGHTS 
FOR CALCULATIONS 


Element 


Symbol 


Atomic 
Weight 


Element 


Symbol 


Atomic 
Weight 


ALUMINUM 


Al 


27 


MAGNESIUM 


Mg 


24 


BORON 


B 


11 


MANGANESE 


Mn 


55 


CALCIUM 


Ca 


40 


NITROGEN 


N 


14 


CARBON 


C 


12 


OXYGEN 


O 


16 


CHLORINE 


CI 


36 


POTASSIUM 


K 


39 


COPPER 


Cu 


64 


SILICON 


Si 


28 


HYDROGEN 


H 


1 


SILVER 


Ag 


108 


IODINE 


1 


127 


SODIUM 


Na 


23 


IRON 


Fe 


56 


SULFUR 


S 


32 


LEAD 


Pb 


207 


ZINC 


Zn 


65 



This not only tells you that iron and sulfur make 
iron sulfide but also that it takes one iron atom and 
one sulfur atom to produce one molecule of FeS. Fur- 
ther, by inserting the atomic weights for the two 
elements from the chart on page 107, the equation 
tells you how much iron and sulfur are needed and 
how much iron sulfide you should get: 

Fe + S — FeS 

56 32 56 + 32 = 88 

You can use the atomic weight numerals to indi- 
cate numbers of grams or any other unit of weight. 
By dividing by 16 you get the number of grams you 
used for experiment on page 22. 

Now take a more complicated equation. 

Let's say you want to produce magnesium carbon- 
ate. The chart of solubilities on page 108 tells you 
that MgCOj is insoluble. \ou should therefore be 
able to precipitate it from a soluble magnesium salt 
— the sulfate, for instance — and soluble sodium 
carbonate: 

MgS0 4 + Na,CO,— MgCOj | + Na 2 SO, 

Now you need to know how much MgS0 4 and how 
much Na,COj you need, and how much MgCOj you 
will get. 

Before you start figuring from the equation above, 
check the chart on page 108, top right. Here you 
will discover that each molecule of magnesium sul- 
fate has seven molecules of water of hydration (7H : 0) 
attached to it, and each sodium carbonate molecule, 
(CONTINUED ON PAGE 108) 



107 



SOLUBILITY OF SALTS 
AND HYDROXIDES 

NITRATES — SOLUBLE— WITHOUT EXCEPTIONS. 
ACETATES — SOLUBLE— WITHOUT EXCEPTIONS. 

CHLORIDES — SOLUBLE— EXCEPT Ag, Hg (MERCU- 

ROUS), AND Pb. 
SULFATES — SOLUBLE — EXCEPT Pb, Ba, Sr (Ca, Ag 

AND Hg SLIGHTLY SOLUBLE). 

NORMAL CARBONATES, PHOSPHATES, SILICATES, 
SULFIDES — INSOLUBLE — EXCEPT Na, K, NH 4 . 

HYDROXIDES — INSOLUBLE — EXCEPT Na, K, NH 4 , 
Ba. (Ca AND Sr SLIGHTLY SOLUBLE.) 



WATER 


OF 


HYDRATION 


(WATER OF CRYSTALLIZATION) 


AgNO, 




NH 4 AI(SO„) 2 -12H 2 


CaCI,-6HjO 




NH 4 CI 


(CaSOJ.-HjO 




Na,B 4 O 7 -10H,O 


CuS0 4 -5H 2 




Na 2 CO,-10H 2 O 


FeCI,-6H,0 




NaCI 


FeCI 2 -4H 2 




NaHCO, 


FeS0 4 -7H 2 




NaHS0 4 -H 2 


KAI(S0 4 ) 2 -12H 2 




NaOH 


KNO, 




Na 2 SO 4 -10H 2 O 


MgS0 4 -7H,0 




Na 2 S 2 3 -5H 2 



Jc^qniLatioinLS — IJoiatiiiiiiLedl 



ten molecules of water (10H 2 O). These do not enter 
into the chemical reaction — but you have to in- 
clude them in the weight of the chemicals. 

Write the atomic weight below each element. Then 
figure the molecular weight of each compound by 
adding the atomic weights of all the atoms found in 
the molecule. 

This is what you get: 

Mg S O t • 7H 2 0+Na, C 3 •10H 2 O — ■ 

24 32 16x4 7x18 23x2 12 16x3 10x18 

24+32+ 64 + 126 46 +12 + 48 + 180 

246 286 



Mg C 3 { + 


Na, S 0, 


17H,0 


24 12 16x3 


23x2 32 16x4 


17x18 


24+12+ 48 


46 +32+ 64 


306 


84 


142 


306 



(When a formula contains subscripts — the small 
numerals that indicate how many of a kind — be 
certain to multiply the atomic weight by ihe number 
indicated by the subscript. In cases where the for- 
mula is preceded by a large number, be sure to mul- 
tiply the molecular weight by this number.) 

Your finished calculation tells you that 216 g (or 
24.6 g or 2.46 g) of magnesium sulfate crystals and 
286 g (or 28.6 g or 2.86 g) of sodium carbonate crys- 
tals will give you 84 g (or 8.4 g or .84 g) magnesium 
carbonate. 

When you get even deeper into chemical mathe- 
matics you will be able to figure out the percentage 
of elements in a compound for which you know the 
formula, or the formula of a compound when you 
know the percentage of elements, or the numbers of 
liters of a gas you prepare in a chemical reaction. 



CHEMISTRY AS A 
HOBBY WILL GIVE 
YOU MANY HOURS 
OF ENJOYMENT. 



CHEMISTRY AS A 
SCIENCE TRAINS 
YOUR REASONING 
AND OBSERVATION. 




108 



Vyiiafs Ahead in Onemisfcry.' 



Tim chemical wonders of today are amazing 
enough — but they are like nothing compared to the 
wonders the future holds in store for the welfare of 
all humanity. 

FOOD — The fertilizers of tomorrow will greatly 
increase the crops grown on farms throughout the 
world. Insect and disease-destroying chemicals will 
make cattle and poultry healthier and better pro- 
ducers of meat. milk, and eggs. Chemicals unknown 
today will make it possible to keep food fresh with- 
out refrigeration in any climate. 

HOMES — The houses of the future will be built 
of more durable materials than any we have today. 
Floors and wall covering will last almost indefinitely. 
New paints will add never-fading colors. 

CLOTHING — Many more man-made fibers will 
be added to those we use today — fibers with longer 
wear; fabrics that are cool in summer, warm in win- 
ter, easy to keep clean. 

HEALTH — The miracle drugs of today have 
wiped out diseases that ranked among our greatest 
killers just a few years ago. In years to come many 
more diseases will disappear from the surface of the 
world under the onslaught of still more effective 
drugs created in the chemical laboratory. 

TRAVEL — Much of the travel of the future will 
be at supersonic speeds. Planes and rockets will re- 
quire materials that can stand tremendous heat and 
new fuels capable of producing enormous energy. 
Chemistry will provide them. 



ATOMIC ENERGY — The force hidden in the 
atom will be turned into light and heat and power 
for everyday uses. Chemists of the future, working 
with their brother-scientists, the physicists, will find 
new ways of harnessing and using the atoms of nu- 
merous elements — some of them unknown to the 
scientists of today. 

Do you want to share in the making of that as- 
tonishing and promising future? 

If you have enjoyed performing the experiments 
in this book, figuring out formulas and equations, 
jotting down observations, you are the kind of per- 
son who has the qualifications for making a success- 
ful career in chemistry. 

If you care to look further into the matter, speak 
to your science teacher about it and chop a line to 
one or ah three of the organizations mentioned below 
and ask for their pamphlets on becoming a chemist: 

American Chemical Society, 
1155 16th Street, N. W., Washington 6, D. C. 

American Institute of Chemical Engineers, 
25 West 45th Street, New York 36, N. Y. 

Manufacturing Chemists' Association, 
1625 I Street, N. \V.. Washington 6, D. C. 

But whatever you decide for the future, keep up 
your interest in chemistry as a hobby. In addition 
to giving you fun and enjoyment, your chemical 
hobby will sharpen your powers of observation and 
reasoning and train your mind for whatever occu- 
pation you decide upon for a life work. 



CHEMISTRY AS A LIFE- 
WORK ENABLES YOU TO 
CONTRIBUTE TO THE 
WELFARE OF MANKIND. 




109 



"Wkere to Get OLemicals and Jc^qTLiipiiieiif 



A great many of the experiments in this book can 
be performed with equipment found around the 
house: water glasses, custard cups, jars, bottles, cans, 
and funnel. For the rest, the following pieces of regu- 
lar chemical laboratory equipment are needed: 

6 lest tubes, regular, 150 mm x 16 mm 
3 test tubes, Pyrex, 150 mm x 16 mm 

1 test tube brush, small 

3 wide-mouth bottles, 4 ozs. 

6 ft. glass tubing, 6 mm outside diameter 

3 ft. rubber tubing, Jjg* inside diameter 

2 No. rubber stoppers, one hole 
1 No. 5 rubber stopper, one hole 

3 No. 5 rubber stoppers, two holes 
1 triangular file, 4' 

1 glass stirring rod, 5* 

1 pkg. filter paper, 12.5 cm. 50 pieces 

1 vial litmus paper strips, blue 

1 vial litmus paper strips, red 

If you can not secure this equipment locally, write 
to one of the companies below asking for price list 
or catalog, including cost of catalog where called for. 
When you receive the answer, mail your order and 
the correct amount by bank check or money order. 

Science Mail Co.. 17-33 Murray St., Whilestonc 57, N. Y. 

(Price list free) 
Winn Chemical Co., 124 West 23rd Si.. New York 11, N. Y. 

(Catalog 25p) 
N. Y. Scientific Supplv Co.. 28 West 30th St., New York 1, 

N. Y. (Catalog 50c) 
Home Lab Supply. 511 Homestead Ave., Mount Vernon, N. Y. 

(Price list free) 
Biological Supplv Co., 1176 Mt. Hope Ave., Rochester 20, 

N.Y. (Catalog 25p) 
A. C. Gilbert Co., P. O. Box 1610, New Haven 6, Conn. 

(Price list free) 
Bio-Chemical Products, 30 Somerset St., Belmont, Mass. 

(Catalog 25e) 
Laboratory Sales, P. 0. Box 161, Brighton, Mass. 

(Catalog 25c) 
The Porter Chemical Co.. Hagerslown. Md. (Price list free) 
Tracey Scientific Laboratories, P. O. Box 615, Evanston, 111. 

(Catalog 25e) 
National Scientific Co., 13 South Park Ave., Lombard, 111. 

(Catalog 35c) 
Hagenow Laboratories. Manitowoc, Wis. (Catalog 20p) 



[lllll I I I I I iHl lllIU I I I lllilj pil-l I I 1 Ml MM 



? 






^^-^x*! 
$ 



CUPRIC 
SULFATE 



CuSOv 

.1 7H i° 



■?c 



M 

i-i 






POTASSIUM 
PERMAN- 
GANATE 

KMnO, 



SODIUM 
Bl SULFATE 



NoHSCV 




IF YOU DECIDE TO USE REGULAR LABORATORY V/ARE 
IN YOUR HOME LAB, GET PRICE LIST FROM SUPPLIER. 



CHEMICALS FOR HOME EXPERIMENTS ARE AVAILABLE 
IN JARS OF UNIFORM SIZE, ALL PROPERLY LABELED. 

Whenever you need a chemical for one of the ex- 
periments described in this book, check the list of 
common chemicals on page 111 to find out where to 
buy it. 

All of these chemicals are, of course, available 
through chemical supply houses. The trouble is that 
many of these houses do not sell to individuals but 
only to schools and established laboratories. Also, 
the chemicals usually come in a standard amount of 
M lb. — or even 1 lb. — where, in home experiments, 
you would need 1 ounce or less. The same is often 
the case when you buy chemicals in a local store. 
The mimmum-sized packages or jars may be so large 
that you couldn't possibly use up the contents in a 
year of experiments. You will probably also have to 
repack what you actually need into glass jars of suit- 
able size for efficiency and to fit your storage space. 

Because of ibis and the inconvenience of having 
to shop around, you may find it advantageous to buy 
your chemicals by the kit, in uniform-sized screw- 
top glass containers. Such kits are available in the 
science department of many hobby and model supply 
stores. 

Chem-Kit No. 1 contains the ten chemicals mark- 
ed ® on the opposite page. Chem-Kit Xo. 2 contains 
the ten chemicals marked □• The kits contain suf- 
ficient amounts of chemicals to perform each experi- 
ment many times over. 

You can also make up your own set of chemicals 
in amounts suitable for home experiments by getting 
them from one of the companies listed to the left. 
Be certain to add the cost of the catalog when you 
write for one and to send the correct amount when 
vou order. 



110 



(^o 



mm on 



a 



lemicais 



Is and 1 heir Jr ormiilas 





CHEMICAL NAME 


FORMULA 


COMMON NAME 


WHERE TO BUY 


m 


ACETIC ACID 


CHjCOOH + H,0 


5% solution: white vinegar 


Grocery 


m 


AMMONIUM CHLORIDE 


NH,CI 


sal ammoniac 


Drug store 


3 


AMMONIUM HYDROXIDE 


NH 5 OH + H 2 


10% solution: household ammonia 
27% solution: strong ammonia 


Grocery 
Drug store 


a 


BORIC ACID 


H 3 BO. 


boric acid 


Drug store 


a 


CALCIUM CARBONATE 


CaCOj 


ihunks: marble, limestone 
powder: precipitated chalk 


Builders' supplies 
Drug store 


D 


CALCIUM HYDROXIDE 


Ca(OH) 2 


slaked lime, garden lime 


Hardware store 


a 


CALCIUM OXIDE 


CaO 


quicklime 


Builders' supplies 


a 


CALCIUM SULFATE 


(CaSOj) »H 2 
CaSO,«2H 2 


plaster of Paris 
gypsum 


Hardware store 
Chemical supplies 


a 


CARBON TETRACHLORIDE 


CC1, 


'arbon tet 


Hardware store 


~ 


COPPER SULFATE 


CuSO^SHjO 


blue vitriol 


Drug store 


B 


FERROUS SULFATE 


FeSOi»7HjO 


iron sulfate, green vitriol, copperas 


Drug store 


E 


GLUCOSE 


C 6 H, 2 6 -|- H 2 


solution: corn syrup 


Grocery- 


D 


HYDROCHLORIC ACID 


HQ + H 2 


25% solution: muriatic acid 


Hardware store 


□ 


HYDROGEN PEROXIDE 


H 2 2 + H,0 


3% solution: peroxide 


Drug store 


■ 


IRON, METAL, POWDER 


Fe 


powdered iron 


Chemical supplies 





MAGNESIUM, METAL 


Mg 


magnesium ribbon 


Chemical supplies 


□ 


MAGNESIUM SULFATE 


MgS0 4 »7H 2 


Epsom salts 


Drug store 


■ 


MANGANESE DIOXIDE 


MnOj 


pyrolusite 


Hardware store 
(flashlight battery) 


□ 


NAPHTHALENE 


CioHj 


moth balls 


Hardware store 


■ 


PHENOLPHTHALEIN 


C 6 H.COOC(C 6 H 4 OH) : 


phenolphthalein 


Drug store 


B 


POTASSIUM ALUMINUM SULFATE 


KA1(S0,) 2 '12H 2 


alum, potassium alum 


Drug store 


a 


POTASSIUM FERROCYANIDE 


K4Fe(CN) 6 »3Hj0 


potassium ferrocyanide 


Chemical supplies 


U POTASSIUM IODIDE 


KI 


potassium iodide 


Drug store 


m 'POTASSIUM NITRATE 


KNOj 


saltpeter, niter 


Drug store 


j POTASSIUM PERMANGANATE 


EMn0 4 


potassium permanganate 


Drug store 


1 SALICYLIC ACID 


dlLOHCOOH 


salicylic acid 


Drug store 


S 1 SILVER NITRATE 


AgNO, 


lunar caustic 


Drug store 


□ SODIUM BICARBONATE 


NaHCOj 


baking soda, bicarb 


Grocery 


■ SODIUM BISULFATE 


NaHSOj'ILO 


82% of Sani-Flush® 


Grocery- 


SODIUM CARBONATE 


Na 2 CO 3 '10H 2 O 
Na 2 C0 3 'H 2 


sal soda, crystal washing soda 
concentrated washing soda 


Grocery 
Grocery 


Q i SODIUM CHLORIDE 


NaCl 


salt, table salt 


Grocery 


Q J SODIUM HYDROXIDE 


NaOH 


lye, caustic soda, Drano* 


Grocery- 





SODIUM HYPOCHLORITE 


NaCIO -J- H 2 


5% solution: laundry bleach, 
Clorox® 


Grocery 





SODIUM POTASSIUM TARTRATE 


NaKCjHjOa • JH 2 


Rochelle salt 


Drug store 





SODIUM SILICATE 


NajSiO, + H,0 


solution: water glass 


Hardware store 


n 


SODIUM TETRABORATE 


Na 2 B 4 Oi«10H 2 O 


borax 


Drug store 


a 


SODIUM THIOSULFATE 


NajSjOi'SHjO 


hypo 


Photo store 





SUCROSE 


CijHsjOii 


cane sugar 


Grocery- 


B 


SULFUR 


S 


powder: flowers of sulfur 
block: sulfur candle 


Drug store 
Hardware store 


B 


ZINC, METAL 


Zn 


zinc 


Hardware store 
(flashlight battery) 





ZINC CHLORIDE 


ZnCl 2 + H 2 


tinners' fluid 


Hardware store 



Note: Chemicals marked D — many of them liquids — are most easily secured in local stores. Chemicals 
marked B are found in Chi-m-Kit No. 1, chemicals marked in Chem-Kit No. 2 (see opposite page). 



Ill 



InA 



ex 



Acetic acid, 90, 91 

Adds, 23, -12, 43; corboxylic, 90; 

fatty, 92, 93; household items 

containing, 44; making, 44; test 

for, 43, 44; traits of, 42 
Acrolein, 93 
Albumin, 97, 99 
Alchsmists, 6, 7, 36 
Alcohols, 79, 8B-B9 
Alum, 64, 65 
Aluminum, 64-65; chloride, 64; 

foil, 72; hydroxide, 65; sulfate, 

64, 65 
Ammonia, 32, 33, 43; fountain, 33; 

making, 33; solubility of, 33; 

uses of, 32 
Ammonium, alum, 64; chloride, 33; 

cycnote, 73; hydroxide, 33, 43 
Apparatus, how to make, 12, 16 
Aristotle, 6 
Arrhenius, Svante, 40 
Atmosphere, 27 
Atomic energy, 5 
Atomic weights, 38, 39, 107 
Atoms, 36, 37, 38, 39 

Baekeland, Leo H., 104 

Balance, hand, 15 

Balloons, 23 

Bases, 23; household items contain- 
ing, 45; test for, 43, 45; traits 
of, 43 

Benzene, 80, 81 

Berzelius, Jons, 36 

Bessemer, Henry, 69 

Borox, 57; bead test, 56 

Boric acid, 57; test for, 57 

Boron, 56 

Boyle, Robert, 6,7 

Bronze, 70 

Calcium, 60-61; bica;bcnote, 60; 

carbonate, 45, 60, 61 ; chloride, 

47, 61 ; hydroxide, 45, 60; 

oxide, 45, 60; sulfate, 60, 61 
Candle, 18-19; contents of, 18 
Carbohydrates, 79, 84-87 
Carbon, 76; atom, 37; compounds, 

23, 76-77, 73, 80-81; forms of, 

77; test for, 77 
Carbonate, calcium, 45, 60, 61; 

copper, 71; cupric, 71; ferric, 

69; iron, 69; magnesium, 63; 

mongonese, 67; potassium, 59; 

sodium, 53; zinc, 63 
Carbon dioxide, 30-31; cycle of, 30; 

making, 30, 31; test for,31; 

uses of, 30 
Carboxylic acids, 79, 90-91 
Casein, 93, 99; glue from, 98; 

making af, 93 
Cavendish, Henry, 28 
Cellulose, 86 
Charles, Jacques, 28 
Cheese, 99 
Chemical, common names. 111; 

formulas. 111; where to buy, 

110, 111 
Chemistry, careers in, 109; future 

of, 109; importance, 4; what it 

■s, 4 
Chemists, 6 
Chloride, aluminum, 64; ammonium, 

33; calcium, 47, 61; copper, 71; 

cupric, 71; cuprous, 71; ferric, 

68; ferrous, 68; iron, 35, 6B; 

magnesium, 62; manganese, 67; 

silver, 72; sodium, 41, 58; zinc, 

23, 47, 62 
Chlorine, 34-35; bleaching with, 

35; ecmpaunds, 34, 35; making, 

35; test for, 34 
Chloroform, 89 
Coal age, 76; mining, 76 
Coagulation, 96, 101 
Colloidal dispersion, 100 
Colloids, 23, 100-101; light 

test for, 101 



Compounds. 22, 23 

Copper, 70-71; carbonate, 71; 

chloride, 71 ; hydroxide, 71 ; 

replacement of, 62, 71; 

salicylate, 91; sulfate, 62, 71; 

sulfide, 53, 71 
Copperas, 69 
Crystallization, 21, 58 
Crystals, 41,64 
Cuprammonium, 103 
Cupric salts, 70, 71 
Cuprous salts, 70, 71 
Curie, Marie, 7, 20 
Curie, Pierre, 7, 20 

Dalton, John, 36, 37 
Davy, Humphry, 7, 59, 60 
Decantation, 20 
Dcmoeritus, 6 
Detergents, 95 

Dispersions, colloidal, 100-101 
Dislillation, destructive, 77; 
of ethanol, 89; of water, 61 

Eggs, protein in, 96-97 
Electrolysis of water, 25 
Elements, 22, 23, 38-39 
Empedocles, 6 
Emulsification, 101 
Equations, chemical, 106-103 
Equipment, laboratory, 8; 

improvised, 9, 11; 

where to buy, 1 10 
Esters, 79, 92 
Ethanol, 83, 89 
Evaporation, 21 

Faraday, Joseph, 18 
Fats, 92-93; extracting, 93; 

test for, 93 
Fehling solution, 85, 87, 93 
Ferric sails, 63, 69 
Ferrous salts, 68, 69 
Fibers, 102-103; tests for, 102, 103 
Filtration, 20, 21 
Fire extinguisher, 30 
Formulas, 74-75, 106; carbcn 

compaunds, 80*81; of common 

chemicals. 111 
Fractionating of oil, 82 
Frasch, Herman, 50 
Fructose, 84 

Gasoline, 82 

Gelatin, 99 

Glass tubes, bending, 13; cutting, 

13; glazing, 13 
Glycerol, 92, 93 
Glossary, 2 
Glucose, 84, 85 
Grahom, Thomas, 100 

Hall, Charles, 64, 65 

Hydrocarbons, 79, 82-S3 

Hydrochloric acid, 34, 44 

Hydrogen, 28-29; making, 28, 29; 
sofety with, 29; test for, 25, 28 

Hydrogen iodide, 49 

Hydrogen peroxide, 26, 27, 67 

Hydrogen sulfide, 52, 53; in chemi- 
cal analysis, 53; making, 53 

Hydroxide, 43; aluminum, 65; 
ammonium, 33, 43; calcium, 60, 
61; copper, 71; cupric, 71; 
ferric, 69; ferrous, 69; iron, 69; 
magnesium, 63; manganese, 66; 
potassium, 94; sodium, 43, 94; 
solubility of, 108; zinc, 63 

Hypo, 49, 51,52, 73 

Indicators, color table, 44, 45; 

homemade, 42; types cf 

laboratory, 43 
Iodide, potassium, 34, 48, 49, 87 
Iodine, 48-49; making, 48, 49; 

removing, 49; solubility of, 48; 

test for, 49; tincture of, 48 
Iodoform, 89 



Iron, 68-69; carbonate. 69; chloride, 
35, 68; hydroxide, 69; oxide, 68; 
salicylate, 91; sulfate, 69; 
sulfide, 53; tannate, 91 

Kalium, 59 

Kekule, August, 80,81 

Kitchen as laboratory, 4 

Laboratory, safety, la; setting up, 

10-11; techniques, 16-17 
Lavoisier, Antoine, 6 
Lime, 43, 60 
Lime water, 31 
Lye, 43 

Magnesium, 62-63; carbonate, 47, 

63; hydroxide, 63; sulfate, 41, 

47, 62, 63 
Manganese, 66-67; carbonate, 67; 

chloride, 67; dioxide, 25, 66; 

hydroxide, 66; sulfate, 66, 67; 

sulfide, 53, 67 
Measurements, 14 
Mendeleeff, Dmitri, 39 
Metalloids, 23 
Metals, 23 (see also individual 

metals); tests for, 53, 56 
Methane, 80,81,83 
Methanol, 88, 89 
Metric system, 14 
Milk, protein in, 93 
Minerals, 54 
Mixtures, 22, 23 
Moseley, Henry, 39 
Muriatic acid, see Hydrochloric 

acid 

Naphthalene, 83 

Natrium, 58 

Neutralization, 46 

Nitrate, potassium, 32, 41, 59; 

silver, 72 
Nitric acid, 42 

Nitrogen, 32-33; in atmosphere, 32 
Non-metals, 23 

Oil, cracking of, 83; crude, 82; 

fractionating of, 82 
Oils, 92-93 
Olein, 92 
Organic compounds, see Carbon 

compounds 
Orsted, Hans C, 64 
Oxide, boric, 57; calcium, 60; 

magnosium, 62; silver, 72; zinc, 

62 
Oxygen, 26-27; in atmosphere, 27; 

making, 27; test for, 25 

Paracelsus, 6, 7 

Peptization, 101 

Periodic table, 38-39 

Permanganate of potassium, 66, 67 

Petroleum, 82 

Phenol, 91 

Photography, 73; without a 
camera, 73 

Photosynthesis, 86 

Plaster of Paris, 61 

Plasties, 104-105; tests for, 104 

Potash, 59, 94 

Potassium, 53, 59; alum, 64; 

carbonate, 59; ferrocyanide, 68; 
flame test for, 59; hydroxide, 94; 
iodide, 34, 48, 49, 27; nitrate, 
32, 41, 59, 61; nitrite, 59; per- 
manganate, 66, 67 

Priestley, Joseph, 7, 26 

Proteins, 79, 96-99; in egg, 96, 
97; in foods, 96, 97; in milk, 
93; tests for, 97, 99 

Proust, Joseph, 37 

Prussian blue, 63 

Pyrolusite, 66 

Radium, 20, 21 

Rayon, 102; making, 103 



Rochelle salt, 85 
Rubber, 82 
Rust, 68 

Safety, 16 

Sal ammoniac, 43 

Salicylic acid, 90, 91 

Salt, table, see Sodium chloride 

Saltpeter, 32,41,59, 61 

Salts, 23, 46-47; household items 

containing, 47; making, 47; 

names of, 46; solubility of, 103 
Scheele, Korl, 7, 26 
Schweitzer's reagent, 103 
Scientific method, 21 
Silicic acid, 55 
Silicon, 54-55 
Silicones, 54 
Silver, 72-73; bromide, 73; 

chloride, 72; nitrate, 72; oxide, 

72; sulfide, 72 
Soap, 94-95; how it acts, 94; 

making, 95; testing, 95 
Soda ash, 59, 94 
Sodium, 53; acetate, 91; aluminate, 

64; bicarbonate, 58; bisulfate, 

42, 53; carbonate, 53, 59, 72; 

chloride, 41, 53; flame test for, 

59; hydroxide, 43, 45, 94, 95; hy- 

pochlorite, 34; salicylate, 91; 

silicate, 54, 55; sulfate, 58; 

sulfide, 53; tetraborate, 57; 

thiosulfate, 49, 51,52, 73 
Solutions, 20, 23, 40-41; behavior 

of, 41; conductivity of, 40; 

making, 41; saturated, 41 
Starch, 86-B7; making, 87; lest 

for, 87 
Stearin, 92 
Steel, 69 

Stoppers, rubber, 12 
Sucrose, 84, 85 
Sugars, 84-85; lest for, 85 
Sulfate, aluminum, 64; calcium, 60, 

61; copper, 62, 71 ,- ferric, 69; 

ferrous, 69; iron, 69; magnesium. 

41, 47, 62, 63; manganese, 65, 67; 

sodium, 58; zinc, 62, 63 
Sulfide, antimony, 53; cadmium, 53; 

copper, 53, 71; cupric, 71; hydro- 
gen, 52, 53; iron, 22, 53; manga- 
nese, 53, 67; silver, 72; sodium, 

53; zinc, 53, 63 
Sulfur, 22, 50-51; casting with, 51; 

forms of, 50, 51; melting, 51; 

precipitated, 51; production 

of, 50 
Sulfur dioxide, 52; rnakinq, 52 
Sulfuric actd, 42 
Sulfurousacid, 44,52 
Symbols, alchemists', 2, 6, 36; 

chemical, 36 

Table salt, see Sodium chloride 
Tannic acid, 90, 91 
Tincture of iodine, 48 
Titration, 46 
Turpentine, 83 

Urea, 78 

Valences, 74-75; chart of, 75 
Vitriol, green, 69 
Vulcanization, 50 

Washington Monument, 64 

Water, 24-25; as a catalyst, 24; 
clearing, 65; composition of, 
24, 26; distilling, 61; elec- 
trolysis of, 25; hardness of, 
61, 95; as solvent, 24 

Water of hydration, 108 

V/aterglass, 55 

Wohler, Friedrich, 7, 78 

Zinc, 25, 62-63; carbonate, 63; 
chloride, 23; hydroxide, 63; 
sulfate, 62; sulfide, 53, 63 



112 




More than 200 color pictures and clear, easy-to-follow directions 
show junior chemists how to prepare a laboratory at home, how to 
buy and make apparatus, and how to set up fascinating, informative 
experiments. In addition, there are facts about famous chemists, 
their contributions, and chemistry in nature and industry. 



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