*CuO
\(\%M_{Cu}=\frac{64}{80}.100\%=80\%\)
\(\%M_O=100-80=20\%\)
*P2O5
\(\%M_P=\frac{31.2}{142}.100\%=43,66\%\)
\(\%M_O=100-43,66=56,34\%\)
*\(H2SO4\)
\(\%M_H=\frac{1}{98}.100\%=1,02\%\)
\(\%M_S=\frac{32}{98}.100\%=32,65\%\)
\(\%M_O=100-32,65-1,02=66,33\%\)
Còn lại e làm tương tự nha