empirical formula is the simplest ratio of whole numbers of components making up a compound. empirical formula can be calculated as follows C H O mass 12.0 g 2.00 g 5.33 g number of moles 12.0 g / 12 g/mol 2.00 g / 1 g/mol 5.33 g / 16 g/mol = 1.00 mol = 2.00 mol = 0.333 mol divide by the least number of moles 1.00 / 0.333 2.00 / 0.333 0.333/ 0.333 = 3.00 = 6.01 = 1.00 the number of atoms C - 3 H - 6 O - 1 empirical formula is C₃H₆O