Let us consider we have 100g of the compound.
So then we will have 63.52g of iron and 36.48g of sulphur.
Fe = 56g/mol
S = 32g/mol
Amount of Fe moles in 100g of compound `= 63.52/56 = 1.1343` mol
Amount of S moles in 100g of compound `= 36.48/32 = 1.0133` mol
So the mole ratio of
So the empirical formula of the compound is FeS.
Usually FeS is also a frequent compound between Fe and S. So the chemical formula of the compound can also be FeS.