A class book of elementary chemistry / by W.W. Fisher.

  • Walter William Fisher
Date:
1897
Catalogue details

Licence: Public Domain Mark

Credit: A class book of elementary chemistry / by W.W. Fisher. Source: Wellcome Collection.

    255/304 (page 235)
    separates as a white gelatinous precipitate, and soluble hydrochloric acid. Many double chlorides may be ob- tained by the union of stannic chloride with alkaline and other metallic chlorides ; they are typified by the compound KgSnClg. The vapour density of stannic chloride is approximately 130, and accordingly the formula is SnCl^ (mol. wt. 260). Stannic Sulphide, SnS2- The disulphide of tin is used, under the name of ‘ Mosaic gold,’ as a bronze powder. It is prepared by heating together an amalgam of tin and mercury with sulphur and sal ammoniac: some calomel and cinnabar sublime and a scaly mass of stannic sulphide remains. A yellow precipitate of stannic sulphide is obtained by the action of hydrogen sulphide on stannic solutions. Like the dioxide, it possesses acid characters, it dis- solves in potash and in alkaline sulphides, producing ' sulpho-stannates. Sodium sulpho-stannates of the com- position Na2SnS3 and Na4SnS4 may be prepared in this manner, as yellowish or nearly colourless crystalline substances. Lead; Pb. Plumbum. Atomic weight, 207. Specific gravity, 11*4. The most important lead ore is galena, PbS, since this is almost the only source from which metallic lead is obtained. The smelting of lead is very simple. After the ore has been separated from earthy matters it is placed on the hearth of a furnace, and heated in an oxidising flame, the air being freely admitted to the furnace. In this roasting sulphur burns ofi* as dioxide, and a portion of the lead is converted into oxide, some sul- phate also being formed. Then the mass is mixed