Chemistry : general, medical, and pharmaceutical including the chemistry of the British Pharmacopœia a manual on the general principles of the science, and their applications in medicine and pharmacy / by John Attfield.

  • Attfield, John, 1835-1911.
Date:
1881
Catalogue details

Licence: Public Domain Mark

Credit: Chemistry : general, medical, and pharmaceutical including the chemistry of the British Pharmacopœia a manual on the general principles of the science, and their applications in medicine and pharmacy / by John Attfield. Source: Wellcome Collection.

    723/850 (page 689)
    GRAVIMETRIC ESTIMATION OF COFPEKj BISMUTH. C89 the vessel witli a watch-glass, and set aside till evolution of hydrogen has ceased and the still acid liquid is colourless. The copper is then washed with hot water by decantation until no trace of acid remains, the precipitate drained, rinsed with strong spirit of wine, dried in the water-oven, and weighed. Process 2.—From a solution acidulated by sulphuric acid and placed in a platinum crucible, copper may be entirely deposited in a coherent form by a weak current of electricity, the crucible being connected with the zinc polo of the batteiy, a platinum spatula suspended in the solution forming the positive pole. The crucible may afterwards be freed from the deposited copper by nitric acid. Process 3.—About three-fourths of a gramme of sulphate of copper is accurately weighed, dissolved in half a litre of water, the liquid boiled; dilute solution of potash or soda is then added till no more precipitate falls, ebullition continued for a short time, and the beaker set aside ; the supernatant liquid is decanted, the precipitate boiled with water twice or thrice, collected on a filter, washed, dried, transferred to a crucible, the filter incinerated, and its ash moistened with a drop of nitric acid; the whole is finally heated strongly, cooled, and weighed. 249'5 parts of sulphate of copper yield 79'5 of oxide, or 635 of metal. Other processes.—Vide Pharmaceutical Journal for April 3, 1880, p. 801. BISMUTH. Dissolve 03 or 0'4 o£ pure oxycarbonate of bismnth (2Bio02C03, HjO) (BismutJd Oarhonas, B. P.) in a small quantity of hydrochloric acid, diluto with water slightly acidulated by hydrochloric acid, pass excess of sulphuretted hydrogen through the liquid, collect the precipitate on a tared filter, wash, dry at 100° C, and weigh. The sulphide must not be exposed too long in the water-oven, or it will increase in weight owing to absorption of oxygen; henco it should be tested in the balance every half-hour during desic-