In the reaction of magnesium and oxygen to form magnesium oxide, 37.14 g of magnesium is reacted with an excess of oxygen. If 27.24 g of magnesium oxide forms, what is the percentage yield?
37.14g = 1.528 moles Mg
27.24g = 0.676 moles MgO
2Mg + O2 → 2MgO
you expected to get 1.528/2 = 0.764 moles MgO. That makes the yield
0.676/0.764 = 0.8848 or 88.48%