What happen when we heat

1. Copper sulphate

2. Ammonium dichromate

1) The blue coloured copper sulphate crystals turns white due to the loss of water molecules. The formula of copper sulphate is CuSO4.5H2O. When copper sulphate is heated, it looses water molecules and hence it looses blue colour.
2)

Ammonium dichromate is a orange compound. It decomposes rapidly on heating to give Nitrogen, steam and Chromium(III) oxide. It is typically used in the volcano presentation in science fairs.

(NH4)2Cr2O7——->Cr2O3+N2+H2O