a)
Gọi \(\left\{{}\begin{matrix}n_{Zn}=a\left(mol\right)\\n_{Mg}=b\left(mol\right)\end{matrix}\right.\left(a,b>0\right)\)
=> 65a + 24b = 8,9 (1)
PTHH:
`Zn + 2HCl -> ZnCl_2 + H_2`
a----->2a------------------->a
`Mg + 2HCl -> MgCl_2 + H_2`
b---->2b------------------>b
b)
\(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
=> a + b = 0,2 (2)
(1),(2) => a = b = 0,1
=> \(\left\{{}\begin{matrix}\%m_{Zn}=\dfrac{0,1.65}{8,9}.100\%=73,03\%\\\%m_{Mg}=100\%-73,03\%=26,97\%\end{matrix}\right.\)
c)
\(V_{dd.HCl}=\dfrac{2.\left(0,1+0,1\right)}{2}=0,2\left(l\right)\)
\(Đặt:n_{Mg}=a\left(mol\right);n_{Zn}=b\left(mol\right)\\ a,PTHH:Mg+2HCl\rightarrow MgCl_2+H_2\\ Zn+2HCl\rightarrow ZnCl_2+H_2\\ b,\Rightarrow\left\{{}\begin{matrix}24a+65b=8,9\\22,4a+22,4b=4,48\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,1\\b=0,1\end{matrix}\right.\\ \Rightarrow\%m_{Zn}=\dfrac{0,1.65}{8,9}.100\approx73,034\%\\ \Rightarrow\%m_{Mg}\approx26,966\%\\ c,n_{HCl}=2.\left(a+b\right)=2.0,2=0,4\left(mol\right)\\ V_{ddHCl}=\dfrac{0,4}{2}=0,2\left(l\right)\)
