4. Calculate the percentage of iron in each of the common iron ores.
5. One ton of steel prepared by the Bessemer process is found by analysis to contain 0.2% carbon. What is the minimum weight of carbon which must be added in order that the steel may be made to take a temper?
CHAPTER XXVIII
COPPER, MERCURY, AND SILVER
| FORMULAS OF OXIDES | ||||||
| SYMBOL | ATOMIC WEIGHT | DENSITY | MELTING POINT | "ous" | "ic" | |
| Copper | Cu | 63.6 | 8.89 | 1084° | Cu2O | CuO |
| Mercury | Hg | 200.00 | 13.596 | -39.5° | Hg2O | HgO |
| Silver | Ag | 107.93 | 10.5 | 960° | Ag2O | AgO |
The family. By referring to the periodic arrangement of the elements (page 168), it will be seen that mercury is not included in the same family with copper and silver. Since the metallurgy of the three elements is so similar, however, and since they resemble each other so closely in chemical properties, it is convenient to class them together for study.
1. Occurrence. The three elements occur in nature to some extent in the free state, but are usually found as sulphides. Their ores are easy to reduce.
2. Properties. They are heavy metals of high luster and are especially good conductors of heat and electricity. They are not very active chemically. Neither hydrochloric nor dilute sulphuric acid has any appreciable action upon them. Concentrated sulphuric acid attacks all three, forming metallic sulphates and evolving sulphur dioxide, while nitric acid, both dilute and concentrated, converts them into nitrates with the evolution of oxides of nitrogen.