|Class 7 Chemistry Physical and Chemical Changes||Crystallisation|
Crystallisation: A physical change
The process of deriving large crystals of pure substances from their solutions is known as crystallisation. It is a physical change. Crystals of salt are obtained by the evaporation of sea water.
Similarly crystals of copper sulphate can be obtained by adding copper sulphate powder to the boiling solution of water and dilute sulphuric acid. This mixture when filtered and allowed to cool produces crystals of copper sulphate.