CARBON AND CARBONATES
The carbon compounds (other than carbonates, which will be subsequently considered) occurring in minerals are generally characterised by their sparing solubility in acids. The diamond is distinguished from other crystals by its hardness, lustre, and specific gravity. It may be subjected to a red heat without being apparently affected, but at a higher temperature it slowly burns away. Graphite, also, burns slowly, but at a lower temperature. The other bodies (coals, shales, &c.) differ considerably among themselves in the temperature at which they commence to burn. Some, such as anthracite, burn with little or no flame, but most give off gases, which burn with a luminous flame. They deflagrate when sprinkled on fused nitre, forming carbonate of potash. In making this test the student must remember that sulphur and, in fact, all oxidisable bodies similarly deflagrate, but it is only in the case of carbon compounds that carbonate of potash is formed. Carbon unites with iron and some of the metals to form carbides; combined carbon of this kind is detected by the odour of the carburetted hydrogen evolved when the metal is treated with hydrochloric acid; for example, on dissolving steel in acid. Get a fix on about this >> |
Previous
Home
