Calculating Relative Formula Mass

1. Calculate the relative formula mass (Mr) of sulfuric acid (H2SO4).        

Relative atomic masses (Ar):  H = 1  O = 16  S = 32

Mr = (2 x 1) + 32 + (4 x 16)

Mr = 98


2. Calculate the relative formula mass (Mr) of magnesium fluoride (MgF2).       

Relative atomic masses (Ar): F = 19  Mg = 24

Mr = 24 + (2 × 19)

Mr = 62