М(AlCl3)=27+35,5*3=133,5
W(Al)=27:133,5*100=20,2
W(Cl)=35,3:133,5*100=26,5
Fe2 (SO4)3=56*2+32*3+16*3*4=400
W(Fe)=112:400*100=28
W(S)=96:400*100=24
W(O)=192:400*100=48
М(KMNO4)=39+55++16*4=158
W(K)=39:158*100=24,6
W(MN)=55:158*100=34,8
W(О)=64:158*100=40,5