Câu 1:
Chỉ Al tác dụng với dd HCl.
PT: \(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
___0,3___________________0,45 (mol)
\(\Rightarrow V_{H_2}=0,45.22,4=10,08\left(l\right)\)
Câu 2:
Gọi: \(\left\{{}\begin{matrix}n_{Al}=x\left(mol\right)\\n_{Zn}=y\left(mol\right)\end{matrix}\right.\)
⇒ 27x + 65y = 21,1 (1)
PT: \(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
\(Zn+2HCl\rightarrow ZnCl_2+H_2\)
Ta có: \(n_{H_2}=\dfrac{14,56}{22,4}=0,65\left(mol\right)\)
Theo PT: \(n_{H_2}=\dfrac{3}{2}n_{Al}+n_{Zn}=\dfrac{3}{2}x+y\left(mol\right)\)
\(\Rightarrow\dfrac{3}{2}x+y=0,65\left(2\right)\)
Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}x=0,3\left(mol\right)\\y=0,2\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow m_{Zn}=0,2.65=13\left(g\right)\)
Bạn tham khảo nhé!
Câu 3:
Gọi: \(\left\{{}\begin{matrix}n_{Mg}=x\left(mol\right)\\n_{Zn}=y\left(mol\right)\end{matrix}\right.\)
⇒ 24x + 65y = 6,85 (1)
PT: \(2Mg+O_2\underrightarrow{t^o}2MgO\)
\(2Zn+O_2\underrightarrow{t^o}2ZnO\)
Ta có: \(n_{O_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
Theo PT: \(n_{O_2}=\dfrac{1}{2}n_{Mg}+\dfrac{1}{2}n_{Zn}=\dfrac{1}{2}x+\dfrac{1}{2}y\left(mol\right)\)
⇒ x + y = 0,2 (2)
Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}x=0,15\left(mol\right)\\y=0,05\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\%n_{Mg}=\dfrac{0,15}{0,15+0,05}.100\%=75\%\)
Bạn tham khảo nhé!