The Molecular Formula tells you the number of atoms of each of the elements in one molecule of a compound. In a previous video, we found the Empirical Formula, and this is a related idea, but not the same thing. The Empirical Formula gives the lowest whole number ratio of the atoms of the elements in a compound. In this video, we show you how to calculate the molecular formula given the Empirical Formula and the Molar Mass. We also talk about how the empirical formula and molecular formula are related.