Mr(SO3) = Ar(S)+Ar(O)*3 = 32+16*3 = 80
Mr(NaOH) = Ar(Na)+Ar(O)+ArH) = 23+16+1 = 40
Mr(H2CO3) = Ar(H)*2+Ar(C)+Ar(O)*3 = 1*2+12+16*3 = 62
Mr(CaCl2) = Ar(Ca)+Ar(Cl)*2 = 40+35.5*2 = 111
Mr(Ba(OH)2) = Ar(Ba)+Ar(O)*2+Ar(H)*2 = 137+16*2+1*2 = 171
Mr(SO3) = Ar(S)+Ar(O)*3 = 32+16*3 = 80
Mr(NaOH) = Ar(Na)+Ar(O)+ArH) = 23+16+1 = 40
Mr(H2CO3) = Ar(H)*2+Ar(C)+Ar(O)*3 = 1*2+12+16*3 = 62
Mr(CaCl2) = Ar(Ca)+Ar(Cl)*2 = 40+35.5*2 = 111
Mr(Ba(OH)2) = Ar(Ba)+Ar(O)*2+Ar(H)*2 = 137+16*2+1*2 = 171