copper oxide

  Preparation of nitrogen Nitrogen is found in both free and combined states. It occupies 78.07% by volume. Nitrogen can be prepared: By heating copper in air: Firstly, air is passed through lime water and then concentrated sulphuric acid to make the air free from carbon dioxide and moistures respectively. The air contains only nitrogen and oxygen which are passed over the heated copper wire as shown in the figure. Here copper combines with oxygen to make copper oxide and nitrogen gas passes over. This nitrogen can be collected by downward displacement of water. By burning phosphorous in air: Nitrogen ... Read more

Metallurgy concentration, roasting, smelting Roasting It is a process wherein the ore is heated either alone or with some other material in excess of air below the fusion point of the ore. Usually, this method is used for sulphide ores. In roasting, definite chemical changes take place to form oxide or chloride of the metal. Ores of metals like zinc, lead, copper and nickel, when roasted in air, are converted to their oxides. Ores of some metals like lead may get partially oxidized and converted to sulphate. In such case, it is called sulphating roasting or partial roasting. Ores of ... Read more