Bài 3:
a, Gọi: \(\left\{{}\begin{matrix}n_{Zn}=x\left(mol\right)\\n_{Fe}=y\left(mol\right)\end{matrix}\right.\) ⇒ 65x + 56y = 14,9 (g) (1)
PT: \(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\)
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
Theo PT: \(n_{H_2SO_4}=n_{Zn}+n_{Fe}=x+y=2.0,125=0,25\left(mol\right)\left(2\right)\)
Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}n_{Zn}=0,1\left(mol\right)\\n_{Fe}=0,15\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{Zn}=0,1.65=6,5\left(g\right)\\m_{Fe}=0,15.56=8,4\left(g\right)\end{matrix}\right.\)
b, Theo PT: \(n_{H_2}=n_{H_2SO_4}=0,25\left(mol\right)\)
PT: \(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)
Theo PT: \(n_{CuO}=n_{H_2}=0,25\left(mol\right)\Rightarrow m_{CuO}=0,25.80=20\left(g\right)\)
