Ответ:

Ar(K2SO4)=(39*2)+32+(16*4)=174

w(K2)= (2*39)/174(только это пиши дробью)=0,448*100=44,8

w(S)=(1*32)/174=0.183*100=18.3

w(O4)=(16*4)/174=0.367*100=36.7

Ar(BaCO3)=137+13+(16*3)=198

w(Ba)=(1*137)/198=0.691*100=69.1

w(C)=(1*13)/198=0.065*100=6.5

w(O3)=(3*16)/198=0.242*100=24.2

Ar(AgNO3)=107+15+(16*3)=170

w(Ag)=(1*107)/170=0.629*100=62.9

w(N)=(1*15)/170=0.088*100=8.8

w(03)=(3*16)/170=0.282*100=28.2

Ar(CuNO3)=64+15+(16*3)=127

w(Cu)=(64*1)/127=0.503*100=50.3

w(N)=(1*15)/127=0.118*100=11.8

w(O3)=(16*3)/127=0.377*100=37.7

Ar(Fe2SO4)=(55*2)+33+(16*4)=207

w(Fe2)=(2*55)/207=0.531*100=53.1

w(S)=(1*3)/207=0.014*100=1.4

w(O4)=(16*4)/207=0.309*100=30.9