c Effect of heat on copper sulphate crystals Crush blue copper sulphate crystals and put them into a dry testtube to a depth of 4 cm Heat the tube gently Note whether vapour collects on the cooler parts change of colour from blue to white and any liquid collecting in the receiving tube Identity of the liquid by measuring the boiling point When all the copper sulphate crystals have changed to white and the tube has cooled hold the tube in your hand and pour the liquid back on to the white crystals Note whether the blue colour restored and if any heat is given back