Empirical formula use with page 344. explain empirical formula by completing the following statements. to determine the empirical for a compound, you must first determine the smallest whale number ratio of the moles of the elements in the compound. this ratio provides the in the empirical formula if the empirical formula differs from the molecular formula, the molecular formula will be a multiple of the empirical formula. the data used to determine the chemical formula may be in the form of or it may be the actual masses. when the percent composition is given, you can assume that the total mass of the compound is 100.0 g to simplify calculations. the of elements in a compound must be_ whole numbers to be used as in the chemical formula.