We have a mass that has 83.5 grams, containing only sulfur and oxygen and we're given the mass of the sulfur. And so what we want to find is the empirical formula? So, if we know it's only sulfur and oxygen, if it's not sulfur, the rest of the mass must be oxygen. So we can actually find the mass of the oxygen by subtracting 83.5 grams of compound, minus our 33.4 grams of sulfur, and we end up having 50.1 grams of oxygen. So, when we're trying to find empirical formulas, what we've got to find is the molar ratio between the elements in that compound. So, we're going to look at our sulfur first. We know we have 33.4 grams of sulfur, and I want to get that into moles. And our molar mass of sulfur is 32.0 grams per mole, and what that gives me is 1.04 moles of sulfur. I'm going to do the same thing for my oxygen, but I have 50.1 grams of oxygen, and my mass of oxygen is 16.0 grams per mole, and that gives me 3.13 moles of oxygen. Now, I can actually look at these ratios and figure out what the formula is. I don't want to leave it as sulfur 1.04, oxygen 3.13. We want nice integers for our subscripts. So, what we want to do is actually divide by the lowest number of moles. In this case, it's going to be the 1.04, and I'm going to divide each of those values by that same number, and what I get is a 1 for the sulfur and a 3 for the oxygen. And so, I can now write my empirical formula because I get sulfur 1, which we're not going to put the subscript in, O3. So, that shows me the molar ratio between the sulfur and the oxygen, and it leaves me with whole number integers for my subscripts.