What change takes place when ferrous sulphate is heated in a dry test tube? Write a balanced chemical equation for the reaction taking place.

When ferrous sulphate crystals are heated in a dry test tube following changes are observed: 

1) A change in color and state occurs. 

2) A gas is produced during this process. 

Crystals of ferrous sulphate are considered to be light green before heating. When heated, ferrous sulphate crystals change to a brown or reddish-brown color. 

As the compound (ferrous sulphate) breaks down into two or more different compounds, it is a decomposition reaction. 

The chemical reaction is as follows:

$2FeS{O}_4\left(s\right)+Heat\to F{e}_2{O}_3+S{O}_2\left(g\right)+S{O}_3\left(g\right)$