MO2 = 2MO = 2*16 = 32
MCuO = MCu + MO = 64 + 16 = 80
MCa(NO3)2 = MCa + 2MN + 6MO = 40 + 2*14 + 6*16 = 164
MHCl = MH + MCl = 1 + 35,5 = 36,5
MAgNO3 = MAg + MN + 3MO = 108 + 14 + 3*16 = 170
MCuSO4 = MCu + MS + 4MO = 64 + 32 + 4*16 = 160
MNaOH = MNa + MO + MH = 23 + 16 + 1 = 40
MAl2O3 = 2MAl + 3MO = 2*27 + 3*16 = 102
MFe(OH)3 = MFe + 3MO + 3MH = 56 + 3*16 + 3*1 = 107
MMg3(PO4)2 = 3MMg + 2MP + 8MO = 3*24 + 2*31 + 8*16 = 262
MHNO3 = MH + MN + 3MO = 1 + 14 + 3*16 = 63
MAl2(SO4)3 = 2MAl + 3MS + 12MO = 2*27 + 3*32 + 12*16 = 342