what is the colour of feso4.7h2o crystals ? how does this colour changes upon heating ?
give balanced chemical equation for the changes ?
Ferrous sulphate is blue-green in colour. On being heated, it loses water of crystallisation and is converted to anhydrous ferrous sulphate. The anhydrous ferrous sulphate on further heating decomposes to ferric oxide, sulphur dioxide and sulphur trioxide. Ferric oxide is reddish brown in colour. This is an example of decomposition reaction. Following is the equation for the reaction
2FeSO4(s)------Heat----> Fe2O3(s) + SO2(g) + SO3(g)
The colour of FeSO4 crystals is pale green.When it is heated, FeSO4.7H2O first loses its water of crystallisation. These pale green crystals then decompose to form Ferric Oxide, Sulphur dioxide and sulphur trioxide. These gases escape inthe atmosphere, but the ferric oxide remains and shows the brown colour crystals.