QUANTITATIVE DETERMINATIONS
table III.—conversion table for specific gravities

57

Specific
gravity*

Per cent, HC1

Specific
gravity*

Per cent, HCl

1.000 | 0.16 | 1.115 | 22.86
1.005 | 1.15 | 1.120 | 23.82
1.010 | 2.14 | 1.125 | 24.78
1.015 | 3.12 | 1.130 | 25.75
1.020 | 4.13 | 1.135 | 26.70
1.025 | 5.15 | 1.140 | 27.66
1.030 | 6.15 | 1.142 | 28.14
1.035 | 7.15 | 1.145 | 28.61
1.040 | 8.16 | 1.150 | 29.57
1.045 | 9.16 | 1.152 | 29.95
1.050 | 10.17 | 1.155 | 30.55
1.055 | 11.18 | 1.160 | 31.52
1.060 | 12.19 | 1.163 | 32.10
1.065 | 13.19 | 1.165 | 32.49
1.070 | 14.17 | 1.170 | 33.46
1.075 | 15.16 | 1.171 | 33.65
1.080 | 16.15 | 1.175 | 34.42
1.085 | 17.13 | 1.180 | 35.49
1.090 | 18.11 | 1.185 | 36.31
1.095 | 19.06 | 1.190 | 37.23
1.100 | 20.01 | 1.195 | 38.16
1.105 | 20.97 | 1.200 | 39.11
1.110 | 21.92 | |

I   ,:

* At 15°.
In carrying out the dilution the required amount of acid is measured in a
dry volumetric flask. This is then poured into a 1000-cc volumetric flask,
the smaller flask being rinsed several times with distilled water and the
rinsings added to the solution in the larger flask. Dilute to the base of the
neck of the 1000-cc flask and mix; finally dilute to the mark and mix
thoroughly.
Sodium Carbonate.—The sodium carbonate to be used as a standard is
best made from sodium bicarbonate, as this salt can usually be obtained in a
high state of purity, so far as other interfering solids are concerned, the only
impurities being water and normal sodium carbonate. By heating to about
300° the following reaction is produced:
2NaHCO_3 -> Na_2CO_8 + H_20 + CO_2.
At the same time water of crystallization is expelled and pure dry sodium
carbonate remains.