COPPER, MERCURY, AND SILVER.
COPPER.
Examine native copper, chalcopyrite, malachite, azurite, copper acetate, copper nitrate, copper sulphate.
278. Occurrence.—Copper occurs both native and in many compounds, being diffused in rocks and, in minute quantities, in soils, waters, plants, and animals. Spain, Chili, and the United States are the chief Cu producing countries. The extensive mines of Michigan yield the native ore. The Calumet and Heela mine alone produces 4,000,000 pounds per month. The most abundant compound of Cu is chalcopyrite, or copper pyrites, CuFeS2. Malachite, which is green, and azurite, which is blue, are carbonates, the former being used for ornamental purposes.
Cu is, next to Ag, the best conductor of electricity and heat among the elements; it is very ductile, malleable, and tenacious.
Cu has two valences, 1 and 2. Symbolize and name its chlorides, iodides, sulphides, and oxides. Cupric compounds, as a rule, are more stable than cuprous.
279. Uses.—Thousands of tons of Cu find use in domestic utensils, ocean vessels, electric wires, batteries, and plating. Name the chief alloys of Cu and their uses. See page 136. How may CuS be obtained? See Experiment 7. Cu2O, cuprous oxide, is used to color glass red. CUSO4 is employed in calico-printing, electric batteries, etc. It is called blue vitriol.
Paris green, used for killing potato-beetles, is composed chiefly of copper arsenite. Write the symbol for this compound. All soluble salts of Cu are poisonous; hence care should be taken not to bring any acid in contact with copper vessels of domestic use. With acetic acid, what would be formed?
MERCURY AND ITS COMPOUNDS.
Examine cinnabar, vermilion, mercury, red oxide, mercurous and mercuric chloride.