Mr(P2O5)=Ar(P)*2+Ar(O)*5=31*2+16*5=+62+80=142
w%(P)=(Ar(P)*2/Mr(P2O5))*100%=(62/142)*100%=43,7%
w%(O)=(Ar(O)*5/Mr(P2O5))*100%=(80/142)*100%=56,3%
ответ:w%(P)=43,7%,w%(O)=56,3%
AxBy
Mr(AxBy)=Ar(A)*x+Ar(B)*y
w%(A)=(Ar(A)*x/Mr(AxBy))*100%
w%(B)=(Ar(B)*y/Mr(AxBy))*100%
