\(n_{HCl}=0.5\cdot1=0.5\left(mol\right)\)
\(n_{H_2}=\dfrac{3.36}{22.4}=0.15\left(mol\right)\)
\(Mg+2HCl\rightarrow MgCl_2+H_2\)
\(0.15.....0.3........................0.15\)
\(CuO+2HCl\rightarrow CuCl_2+H_2O\)
\(0.1.........0.5-0.3\)
\(m_A=0.15\cdot24+0.1\cdot80=11.6\left(g\right)\)