The purpose of this lab is to determine the empirical formula of the compound magnesium oxide. The empirical formula is the simplest whole number ratio of the elementsi n a compound. One mole of a substance has the number of moles of different types of atoms in the same ratio as the stoichiometric ratio. To find the empirical formula of a compound by performing an experiment a person would, determine the mass of each element in the compound, calculate the number of moles of each element in the sample and then write the molar ratio of each element as the smallest possible whole number. The empirical formula for magnesium oxide is MgO. It has a 1:1 ratio of magnesium to oxygen. After completing the experiment, the results should show a 1:1 ratio of magnesium to oxygen.