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
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".
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.
Copper is prepared for smelting in a number of different stages:
- concentration of the ore by floatation,
- roasting of the ore,
- 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.
- a metallic element, which has a characteristic reddish-brown
- 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.
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.
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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