Ferrous sulphate crystals lose water when heated. FeSO 4 . 5 H 2 O ( l ) Hydrated Ferrous Sulpahte FeSO 4 ( l ) Anhydrous Ferrous Sulpahte + 5 H 2 O ( g ) Water. As a result of the creation of anhydrous ferrous sulphate , their colour changes from light green to white
