Question

Brown coloured copper powder on heating in air turns into black coloured substance

Answer 1

Reaction: FeSO4 --> Fe2O3 + SO2 + SO3

This is a thermal decompostion reaction which is taking place.

Iron Sulphate decomposes to form Iron (ii) oxide and Sulphur dioxide and Sulphur trioxide.

Hope it helped. Good luck.

Answer 2

2cu + o2 - 2cuo as copper reacts with oxygen it forms copper oxide