Odpowiedź:
mFe203 = 2 × 56 u + 3 × 16 u = 112 u + 48 u = 160 u
mMgS = 24 u + 32 u = 56 u
mAlCl3 = 27 u + 3 × 35 u = 27 u + 105 u = 132 u