\(n_{HCl}=0,2.1,5=0,3\left(mol\right)\\ Đặt:\left\{{}\begin{matrix}n_{CuO}=a\left(mol\right)\\n_{MgO}=b\left(mol\right)\end{matrix}\right.\left(a,b>0\right)\\ CuO+2HCl\rightarrow CuCl_2+H_2O\\ MgO+2HCl\rightarrow MgCl_2+H_2O\\ \rightarrow\left\{{}\begin{matrix}80a+40b=20\\2a+2b=0,3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,35\\b=0,2\end{matrix}\right.\)
Em xem lại đề bài 1
Bài 2:
\(m_{Cu}=3\left(g\right)\\ m_{hh\left(Zn,Fe\right)}=21,6-3=18,6\left(g\right)\\ Đặt:\left\{{}\begin{matrix}n_{Zn}=a\left(mol\right)\\n_{Fe}=b\left(mol\right)\end{matrix}\right.\left(a,b>0\right)\\ Zn+H_2SO_4\rightarrow ZnSO_4+H_2\\ Fe+H_2SO_4\rightarrow FeSO_4+H_2\\ \rightarrow\left\{{}\begin{matrix}65a+56b=18,6\\a+b=0,3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,2\\b=0,1\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}m_{Zn}=0,2.65=13\left(g\right)\\m_{Fe}=0,1.56=5,6\left(g\right)\end{matrix}\right. \)
