CuCI2
Mr(CuCI2)=64+35*2=134
FeS
Mr(FeS)=56+32=88
Al2(SO4)3
Mr(Al2(SO4)3)=27*2(32+16*4)*3=214
MgO
Mr(MgO)=24+16=40
Fe(OH)3
Mr(56(1+16)*3)=107
CuCI2
Mr(CuCI2)=64+35*2=134
FeS
Mr(FeS)=56+32=88
Al2(SO4)3
Mr(Al2(SO4)3)=27*2(32+16*4)*3=214
MgO
Mr(MgO)=24+16=40
Fe(OH)3
Mr(56(1+16)*3)=107