The molecular problem for aluminum oxide is Al2O3 Atomic mass of Al = 26.982 Atomic mass of O = 16 From the problem, 1 mole of AL2O3 contains: 2 g-atom of Al or 2 x 26.982 = 53.964 g 3 g-atom of O or 3 x 16 = 48 g the mass of 1 mole of Al2O3 is equal to 53.964 + 48 = 101.964 g