Page 26 - Curriculum Visions Dynamic Book

Copper colours
A characteristic of many metals is that their compounds produce a variety of coloured substances, usually quite unlike the colour of the metals in their native state.
Copper forms several such compounds. For example, copper oxide is black; copper carbonate is green; copper sulphate and copper nitrate are blue. Copper sulphide may be black or, if it is an ore, brassy yellow, depending on the amount of
iron it contains.
Some examples of these colours are shown on this page, but other examples can be found on page 6.
EQUATION: Producing copper nitrate
Copper oxide + nitric acid ➪ copper nitrate + water CuO(s) + 2HNO3(l) ➪ Cu(NO3)2(s) + H2O(l)
 Crystals of copper nitrate form. They are
a brighter blue than copper sulphate.
 Nitric acid is being poured onto black copper oxide.
 This represents copper nitrate.
Nitrogen
◆
Copper
 Pure copper is an orangy colour, as shown by these coppered nails.
Oxygen
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