Explain how impure copper sulphate can be purified by crystallization.
Crystallization is a process that separates a pure solid in the form of its crystals from a solution.
The various steps of purification used for impure copper sulphate are:
1. Take some (approximately 5g) impure sample of copper sulphate in a china dish.
2. Dissolve it in the minimum amount of water and filter out the impurities.
3. Evaporate water from the copper sulphate solution so as to get a saturated solution.
4. Cover the solution with a filter paper and leave it undisturbed at room temperature to cool slowly for a day.
5. Then crystals of copper sulphate in the china dish are obtained.