So actual yield divided by theoretical yield multiplies that by 100 to get our percent because otherwise this guy is a fraction and that will give you percent yield. Now, let's look at the following reaction. So in the following reaction, 1 mol of methane reacts with two moles of oxygen to produce 1 mol of carbon dioxide and two moles of water. Now, let's suppose we react 1 mol of methane with two moles of oxygen, and we find that our actual yield in grams was 38 grams of carbon dioxide. Now, if we find our theoretical yield, we could then find our percent yield. How would we go about finding our theoretical yield?