Researches on the arseniates, phosphates, and modifications of phosphoric acid / by Thomas Graham.

  • Thomas Graham
Date:
1904
Catalogue details

Licence: In copyright

Credit: Researches on the arseniates, phosphates, and modifications of phosphoric acid / by Thomas Graham. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    In Exp. i. 42.42 grs. crystallized salt lost 2. 26.04 Water. 21.13 49-81 per cent. 12.94 49.69 20.40 49.76 3 4i- Mean 49-75 These results exhibit the entire quantity of water which the salt abandons by the action of heat alone; for an adopter being applied to the flask and made tight by luting, the salt was in each case subsequently heated for a few minutes to full redness, without any further loss of weight. No sensible absorption of carbonic acid occurred when the experiment was conducted in this manner. The salt was not fused ; indeed it is not fused by a strong white heat. But the calcined salt still contains water, as may be shown by fusing it with any body capable of combin- ing with the excess of alkali. A quantity of bichromate of potash in a glass tube may easily be kept in a state of fusion by the flame of a lamp. On throwing the calcined subarseniate into that fused and anhydrous salt, a notable quantity of water was given off, which condensed in the upper part of the tube. Exp. 1. About 50 grains of the fused bichromate of potash, as it falls to pieces in the progress of cooling, but still warm, were introduced into the platinum flask con- taining 13.1 grains of calcined salt of Experiment 2nd above, and the whole maintained in a state of fusion for a considerable time at a low red heat, by means of a spirit-lamp. The salt lost 0.16 grain additional, and no green oxide of chromium was formed. This is an addi- tional loss of 0.62 per cent, on the crystallized salt, and makes the entire water amount to 50.31 per cent. Exp. 2. 25.57 grains of crystallized subarseniate were introduced, with a little water, into a crucible containing already 20 grains of pure anhydrous arsenic acid, calcined
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