Mr(SO3) = 32 + 16*3 = 80
Mr(P2O5) = 31*2 + 16*5 = 142
Mr(H2SO4) = 1*2 + 32 + 16*4 = 98
Mr(CaCO3) = 40 + 12 + 16*3 = 100
Mr(Fe(OH)3) = 56 + 16*3 + 1*3 = 107
Mr(O2) = 16*2 = 32
Mr(Cl2) = 35*2=70
Mr(SO3) = 32 + 16*3 = 80
Mr(P2O5) = 31*2 + 16*5 = 142
Mr(H2SO4) = 1*2 + 32 + 16*4 = 98
Mr(CaCO3) = 40 + 12 + 16*3 = 100
Mr(Fe(OH)3) = 56 + 16*3 + 1*3 = 107
Mr(O2) = 16*2 = 32
Mr(Cl2) = 35*2=70