What is meant by 'hydrated' and 'anhydrous' salts? Explain with examples.

The salts which contain water of crystallisation are called hydrated salts. Example: Copper sulphate crystals contain 5 molecules of water of crystallisation. The salts which have lost their water of crystallisation are called anhydrous salts. Example: On strong heating, copper sulphate crystals lose all the water of crystallisation and form anhydrous copper sulphate which is white in colour.