% composition = Ar/Mr x 100%
MM (molar mass) ZnSO₄ = 161 g/mol
AM (atomic mass) Zn = 65.38 g/mol
% Zn = 65.38/161 x 100% = 40.6%
AM (atomic mass) S = 32 g/mol
% Zn = 32/161 x 100% = 19.9%
AM (atomic mass) O = 16 g/mol
% Zn = 4.16/161 x 100% = 39.6%
