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Chemical and physical properties of copper

Answer Text:
Properties of copper.
a. Physical properties
- Soft red-brown metal.
- Melting point of `1083^oC` and a boiling point of `2595^oC`
- Density is `8.92gcm^(-3)` and electrical conductivity is about `5.93 xx 10^(-9) Ώ^(-1)m^(-1)`
b. Chemical properties
(i). It does not react with cold water or steam.
(ii). Heating in air
- When heated in air it forms a black layer of copper (II) oxide on its surface.
- Finely divided copper burns with a blue flame.
Equation:
`2Cu(s) + O_2(g) to 2CuO(s)`
(Red brown) (Black)
(iii). Reaction with chlorine
- Cu reacts with chlorine in presence of heat to form green copper (II) chloride.
Equation:
`Cu(s) + Cl_2(g) to CuCl_2(s)`
(iv). Reaction with Acids.
- Copper does not react with dilute hydrochloric, nitric and sulphuric acids.
- However it reacts with 50% Nitric acid, concentrated Nitric acid and concentrated sulphuric acid.
-With 50% Nitric (V) acid
- Copper reduces the nitric acid to nitrogen monoxide.
Equation;
`3Cu(s) + 8HNO_3(l) to 3Cu(NO_3)_2 (aq) + 4H_2O(l) + 2NO(g)`;
-With concentrated Nitric (V) acid
- Copper reduces the acid to brown nitrogen (IV) oxide/Nitrogen dioxide gas.
Equation:
`Cu(s) + 4HNO_3(l) to Cu (NO_3)_2(aq) + 2H_2O(l) + 2NO_2(g)`
-With concentrated sulphuric acid.
-The sulphuric acid is reduced to sulphur (IV) oxide.
Equation:
`Cu(s) + 2H_2SO_4(aq) to CuSO_4 (aq) + 2H_2O(l) + SO_2 (g)`