How do I calculate the relative formula mass of FeSO4 and the number of moles, when the formula mass of O=16, S=32, Fe=56 and the mass of FeSO4= 380g

The formula mass (Mr) of FeSO4 is the total mass of all the individual elemenets added together. So the Mr of FeSO4 = (1 x Fe) + (1 x S) + (4 x O) = 56 + 32 + 4x16 = 152 To calculate moles, the equation for moles is Mass divided by Mr (mass/Mr). Moles of FeSO4 = Mass/Mr = 380 / 152 = 2.5 moles