British weights and measures. | Metric weights and measures. | ||||||
Grains weight of Substance. | = | Grain measures of Vol. Sol. | or | Grams, wt. of Substance. | = | C. C. of Vol. Sol. | |
Ferri Arsenias | 100.0 | = | 225 | or | 10.0 | = | 22.5 |
Ferri„ Carb. Sacch | 30.0 | = | 287.5 | or | 3.0 | = | 28.75 |
Ferri„ Phosphas | 30.0 | = | 279 | or | 3.0 | = | 27.9 |
Ferri„ Sulphas | 42.1 | = | 500 | or | 4.21 | = | 50.0 |
Ferri„ Sulphas„ Exsiccata | 10.0 | = | 191 | or | 1. | = | 19.1 |
Ferri„ Sulphas„ Granulata | 41.7 | = | 500 | or | 4.17 | = | 50.0 |
VOLUMETRIC SOLUTION OF HYPOSULPHITE OF SODIUM.
(Hyposulphite of Sodium crystallised, = 248.)
Take of
Hyposulphite of Sodium, in crystals | 280 grains |
Distilled Water | a sufficiency |
Dissolve the hyposulphite of sodium in 10,000 grain-measures of water. Fill a burette with this solution, and drop it cautiously into 1,000 grain-measures of the volumetric solution of iodine, until the brown colour is just discharged. Note the number of grain-measures (n) required to produce this effect; then put 8,000 grain-measures of the same solution into a graduated jar, and augment this quantity by the addition of distilled water until it amounts to gram-measures. If, for example, n=950, the 8,000 grain-measures of solution should be diluted to the bulk of =8,421 grain-measures. 1,000 grain-measures of this solution contain 24.8 grains of the hyposulphite (110th of , in grains), and therefore correspond to 12.7 grains of iodine (110 th of an atomic weight in grains).
Grammes and cubic centimetres may be employed instead of grains and grain-measures, but for convenience 110 th of the numbers should be taken. 100 cubic centimetres of this solution contain 2.48 grammes of the hyposulphite (1100 th of ,, in grammes), and therefore correspond to 1.27 gramme of iodine (1100th of an atomic weight in grammes).
This solution is used for testing the following substances.