Regrettably, the chemical equation you provided is unbalanced and does not reflect an actual chemical reaction.
Fe (iron) and FeSO4 (iron(II) sulfate) cannot react with each other to produce Fe2(SO4)3 (iron(III) sulfate) and FeSO4.
Here is an example of how a reaction might occur between iron and sulfate:
Fe + CuSO4 -> FeSO4 + Cu
Where iron reacts with copper(II) sulfate to produce iron(II) sulfate and copper.
If you have another chemical equation that needs explaining, please provide it to us!