PTHH:
\(MgO+2HCl\rightarrow MgCl_2+H_2O\) (1)
\(Fe_2O_3+6HCl\rightarrow2FeCl_3+3H_2O\) (2)
\(ZnO+2HCl\rightarrow ZnCl_2+H_2O\) (3)
\(CuO+2HCl\rightarrow CuCl_2+H_2O\) (4)
Ta có: \(n_{HCl}=\dfrac{150.7,3\%}{36,5}=0,3\left(mol\right)\)
Theo PT: \(\left\{{}\begin{matrix}n_{Cl}=n_{HCl}=0,3\left(mol\right)\\n_O=\dfrac{1}{2}n_{HCl}=0,15\left(mol\right)\end{matrix}\right.\)
`=>` \(\left\{{}\begin{matrix}m_{KL}=11,5-0,3.35,5=0,85\left(g\right)\\m_O=0,15.16=2,4\left(g\right)\end{matrix}\right.\)
`=>` \(m=m_{oxit}=0,85+2,4=3,25\left(g\right)\)