Copper

Copper, Cu, is a rose red Transition Metal Element, found in Group Ib of the periodic table.

Atomic Number : 29
Relative Atomic Mass : 63.54
Melting Point : 1080 degC
Melting Point : 2500 degC
Relative Density : 9.0

Discovery

Copper appears to have been known from ancient times. The early use of copper probably resulted from the natural occurrence of copper in native form. The "Copper Age" followed the "Stone Age".

Occurrence

Copper is an abundant metallic element which is found in many locations.

Copper occurs in native form (i.e. as nuggets of the free metal) and in oxide ores (e.g. cuprite, Cu2O) and in sulphide ores (e.g. chalcocite, CuS2, and Chalcopyrite, CuFeS2 or Cu2S.Fe2S3 and Bornite, Cu3FeS3).

Copper also occurs as basic carbonates (Malachite, CuCO3.Cu(OH)2, Azurite, 2CuCO3.Cu(OH)2, and Atacamite, CuCl3.3Cu(OH)2. Native Copper occurs in Sweden, in the Ural mountains, and in large quantities in America, near Lake Superior. This copper usually contains small quantities of silver, bismuth, and lead, Pb.

Extraction

Copper is prepared for smelting in a number of different stages:

concentration of the ore by floatation,
roasting of the ore,
smelting,
conversion of the matte to "Blister Copper", and
refining of the "Blister Copper".

Copper is also extracted by reduction on heating with carbon from its oxide ores (e.g. cuprite) and its carbonate ores (e.g. malachite).

Copper is extracted by smelting from its sulphide ores (e.g. copper pyrites), from which a large amount of copper is obtained.

Preparation

Manufacture

Properties

Copper is

a metallic element, which has a characteristic reddish-brown colouration,
when pure is very malleable and ductile and can be rolled into sheets, hammered into thin leaves, and drawn into wire, and
is an excellent conductor of heat and electricity.

Reactions

Copper does not burn in air, but is slowly oxidised to cuprous oxide and cupric oxide on heating to redness.

>
	     2 F2   +   2 H2O   ==>  4 HF   +    O2

Copper is below hydrogen in the electrochemical series and thus does not react with acids to liberate hydrogen, unless they are also strong oxidising agents. Thus, copper metal will not react with dilute sulphuric acid or with hydrochloride acid, HCl, but it reacts with nitric acid to form oxides of nitrogen.

Copper metal sheets are used for roofing and on contact with the moist atmosphere a green layer is formed on the surface of the metal. This surface layer was thought to be basic copper carbonate. However, in 1929AD, Vernon and Whitby demonstrated that this layer is composed of basic copper sulphate in locations inland and basic copper chloride near the sea.

Uses

Copper is widely used

in the electrical industry,
in cooking utensils and in brewing vats,
in boilers and fire-boxes in locomotives and steam-engines, and
is a constituent in many alloys.

Detection and Analysis

Copper is detected by the characteristic blue colouration of its salts, and the formation of a deep blue complex on the addition of ammonia.

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