Tuesday, October 7, 2008

reactions of copper- notes/ IGCSE / GCSE

When copper is heated in a flame, it turns black with a coating of copper (II) oxide.
Copper+ oxygen --> copper(II) oxide
2- This is an example of thermal decomposition. Copper (II) oxide is a base- it reacts with acids to form salts.
Base+ acid--> salt + water
Copper(II) sulphate + nitric acid--> copper nitrate + water
3- The formation of the deep blue complex ion with ammonia is used as a test for the presence of copper in solution. Other metals give green-blue solutions for example nickel or cobalt, but only copper forms this colored complex.
Here, ammonia (NH3) is added to copper(II) sulpate (CuSO4). The result is a pale blue precipitate, which is Cu(OH)2.
NH3 Add more the product is
(Cu(H20)2 (NH3)4 ) 2+ )
Compound Color
Iron(II) chloride Green
Iron(III) chloride Brown
Copper sulphate Blue
Copper carbonate Blue green
Copper oxide Black
Copper nitrate Blue
Copper chloride Green
Other reactions:
Fe + Hcl--> Fecl2
Cuo + Hcl --> Cucl2 + H2o
Cu + Hno3--> Cu(No3)2 + H2o + No2

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chemistry notes / igcse-gcse- Olevel