CuO+2HCl\(\rightarrow\)CuCl2+H2O
MgO+2HCl\(\rightarrow\)MgCl2+H2O
nHCl=0,2.2=0,4 mol
Gọi a là nCuO b là nMgO
Ta có\(\left\{{}\begin{matrix}\text{80a+40b=12}\\\text{2a+2b=0,4}\end{matrix}\right.\rightarrow a=b=0,1\)
%mCuO=\(\frac{\text{0,1.80}}{12}.100\%\)=66,67%