empirical formula is the simplest ratio of whole numbers of components in a compound calculating for 100 g of the compound C H I mass 3.05 g 0.26 g 96.69 g number of moles 3.05 g / 12 g/mol 0.26 g / 1 g/mol 96.69 g / 127 g/mol = 0.254 mol = 0.26 mol = 0.7613 mol divide by the least number of moles 0.254/ 0.254 = 1.0 0.26 / 0.254 = 1.0 0.7613 / 0.254 = 2.99 when rounded off C - 1 H - 1 I - 3