Iron (II) sulfate also known as ferrous sulphate. Its chemical formula is FeSO₄, and formula weight is the sum of the atomic weights of all atoms that are present in a given chemical formula.
Molar mass of Fe is 55.8450 g/mol
Molar mass of S = 32.065 g/mol
Molar mass of oxygen = 15.999 g/mol
Now add the masses according to formula:
55.8450 + 32.065 + 4(15.999) = 151.96 is the formula weight of FeSO₄
