# Example 1 - Empirical Formula

Determine the empirical formula of a compound which has a percentage of composition Mg: 20.2%, S: 26.6%, O: 53.2%. [Relative atomic mass: Mg = 24; S = 32; O = 16]

 Element Mg S O Percentage 20.2% 26.6% 53.2% Mass in 100g 20.2g 26.6g 53.2g Number of mole $20.2 24 =0.8417mol$ $26.6 32 =0.8313mol$ $53.2 16 =3.325mol$ Simple ratio $0.8417 0.8313 =1$ $0.8313 0.8313 =1$ $3.325 0.8313 =4$