Question

Why does the crystals of copper sulphate turn white on heating?

Answer 1

Answer:

Because copper sulphate loses its 5 molecules of water of crystallization which are necessary for it to crystallize out from its aqueous solution so it turns white

Answer 2

Answer: because anhydrous copper sulphate is formed.

Explanation:

CuSO4.5H2O(blue) + Heat ———CuSO4(white) + 5H2O

when the crystals copper sulphate is heated for some time, the blue colour of it disappears and it becomes white-gray in colour. This is because the water molecules are lost on heating and copper sulphate pentahydrate (5 molecules of water H20) is converted to anhydrous copper sulphate( no water ).

hope this helps...