Mr (BaSO4) = Ar(Ba)+ Ar(S) + 4Ar(O) = 137+32+64 = 233
Mr (HNO3) =Ar(H) + Ar(N)+ 3Ar(O) = 1+14+48 =53
Mr (CuCl2) = Ar(Cu) +2Ar(Cl) = 64+ 2*35 = 134
Mr ( Al2(SO4)3) = 2Ar(Al) + 3Ar(S) + 12(O) = 340
Mr (Cu(OH)2) = Ar(Cu) +2Ar(O) + 2Ar(H) = 98
Mr (AgNO3) = Ar(Ag) + Ar(N) + 3Ar(O) = 108+14+48=170
Mr (BaCl2) = Ar(Ba) + 2Ar(Cl) = 137+70=207
Mr(H2SO4) = 2Ar(H) + Ar(S) + 4Ar(O)= 2+32 + 64 =98