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"A Textbook of Assaying: For the Use of Those Connected with Mines."

gr. 0.838; it
contains 84 per cent. by weight of alcohol.)--It should burn with a
non-luminous flame and leave no residue. It is used for washing
precipitates where water is inapplicable, and for facilitating drying.
~Ammonia~, NH_{3}. (Commercial ammonia, a solution having a sp. gr. of
0.88 to 0.89, and containing about 33 per cent. of ammonia.)--It is used
as an alkali (more commonly than soda or potash), since an excess of it
is easily removed by boiling. The salts of ammonium formed by it may be
removed by igniting, or by evaporating in a porcelain dish with an
excess of nitric acid. It differs in a marked way from soda or potash in
its solvent action on the oxides or hydrates of the metals. Salts of the
following metals are soluble in an ammoniacal solution in the presence
of ammonic chloride:--copper, cadmium, silver, nickel, cobalt,
manganese, zinc, magnesium, sodium, potassium, and the alkaline earths.
~Dilute Ammonia~ is made by diluting 1 vol. of commercial ammonia with 2
of water. The dilute ammonia is always used; but in assays for copper a
stronger solution (1 of strong ammonia to 1 of water) is required.
~Ammonic Carbonate~ (Am_{2}CO_{3}) is prepared by dissolving one part of
the commercial sesquicarbonate of ammonia in four parts of water, and
adding one part of strong ammonia.


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