To balance the chemical equation, we need to make sure that the number of atoms of each element on the reactant side is equal to the number of atoms on the product side.Fe + O2 Fe2O3First, balance the iron Fe atoms:4Fe + O2 2Fe2O3Now, balance the oxygen O atoms:4Fe + 3O2 2Fe2O3The balanced chemical equation is:4Fe + 3O2 2Fe2O3