Describe giving all practical details, how would you prepare :
(a) copper sulphate crystals from a mixture of charcoal and black copper oxide,
(b) zinc sulphate crystals from zinc dust (powdered zinc and zinc oxide),
(c) sodium hydrogen carbonate crystals.
(d) Calcium sulphate from calcium carbonate.
What would you observe when crystals of copper (II) sulphate and iron (II) sulphate are separately heated in two test tubes ?