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Trong \(20,4g\) hỗn hợp có: \(\left\{{}\begin{matrix}n_{Zn}=a\left(mol\right)\\n_{Fe}=b\left(mol\right)\\n_{Al}=c\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow65a+56b+27c=20,4\left(1\right)\)
\(n_{H_2}=\dfrac{10,08}{22,4}=0,45mol\)
\(BTe:2n_{Zn}+2n_{Fe}+3n_{Al}=2n_{H_2}\)
\(\Rightarrow2a+2b+3c=2\cdot0,45\left(2\right)\)
Trong \(0,2mol\) hhX có \(\left\{{}\begin{matrix}Zn:ka\left(mol\right)\\Fe:kb\left(mol\right)\\Al:kc\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow ka+kb+kc=0,2\)
\(n_{Cl_2}=\dfrac{6,16}{22,4}=0,275mol\)
\(BTe:2n_{Zn}+3n_{Fe}+3n_{Al}=2n_{Cl_2}\)
\(\Rightarrow2ka+3kb+3kc=2\cdot0,275\)
Xét thương:
\(\dfrac{ka+kb+kc}{2ka+3kb+3kc}=\dfrac{0,2}{2\cdot0,275}\Rightarrow\dfrac{a+b+c}{2a+3b+3c}=\dfrac{4}{11}\)
\(\Rightarrow3a-b-c=0\left(3\right)\)
Từ (1), (2), (3)\(\Rightarrow\left\{{}\begin{matrix}a=0,1mol\\b=0,2mol\\c=0,1mol\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}m_{Zn}=6,5g\\m_{Fe}=11,2g\\m_{Al}=2,7g\end{matrix}\right.\)
a) \(2Al+6HCl\rightarrow2AlCl_3+3H_2\left(1\right)\\ Fe+2HCl\rightarrow FeCl_2+H_2\left(2\right)\\ 2Al+2NaOH+2H_2O\rightarrow2NaAlO_2+3H_2\)
Cho hỗn hợp tác dụng với NaOH, chất rắn không tan là Fe
=> mFe= 1,12 (g) \(\Rightarrow n_{Fe}=0,02\left(mol\right)\)
Ta có: \(n_{H_2\left(2\right)}=n_{Fe}=0,02\left(mol\right)\)
=> \(n_{H_2\left(1\right)}=\Sigma n_{H_2}-n_{H_2\left(2\right)}=0,065-0,02=0,045\left(mol\right)\)
\(\Rightarrow n_{Al}=\dfrac{2}{3}n_{H_2\left(1\right)}=0,03\left(mol\right)\)
\(\Rightarrow m_{Al}=0,03.27=0,81\left(g\right)\)
\(\Rightarrow\%m_{Al}=41,97\%,\%m_{Fe}=58,03\%\)
b) \(m_{FeCl_2}=0,02.127=2,54\left(g\right)\\ m_{AlCl_3}=0,03.133,5=4,005\left(g\right)\)
Gọi số mol của Zn, Mg và Fe lần lượt là x, y và z mol
TN1: tác dụng với dung dịch HCl tạo 0,5 mol khí H2
Đáp án: B
\(n_{O\left(oxide\right)}=n_{H_2O}=2n_{O_2}=2\cdot\dfrac{4,48}{22,4}=0,4mol\\ n_{Cl^{^-}}=n_{HCl}=2n_{H_2O}=0,8mol\\ m=12+35,5.0,8=40,4g\)
a) PTHH : \(Fe+2HCl-t^o->FeCl_2+H_2\) (1)
\(2Fe+3Cl_2-t^o->2FeCl_3\) (2)
\(Cu+Cl_2-t^o->CuCl_2\) (3)
b) Theo pthh (1) : \(n_{Fe}=n_{H2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
\(\Rightarrow m_{Fe}=0,1.56=5,6\left(g\right)\)
Theo pthh (2) và (3) : \(\Sigma n_{Cl2}=\dfrac{3}{2}n_{Fe}+n_{Cu}\)
\(\Rightarrow\dfrac{6,72}{22,4}=\dfrac{3}{2}.0,1+n_{Cu}\)
\(\Rightarrow0,3=0,15+n_{Cu}\)
\(\Rightarrow n_{Cu}=0,15\left(mol\right)\)
\(\Rightarrow m_{Cu}=0,15.64=9,6\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{Fe}=\dfrac{5,6}{5,6+9,6}\cdot100\%\approx36,84\%\\\%m_{Cu}=100\%-36,84\%=63,16\%\end{matrix}\right.\)
\(n_{Cu}=a\left(mol\right),n_{Fe}=b\left(mol\right),n_{Al}=c\left(mol\right)\)
\(m_X=64a+56b+27b=35.7\left(g\right)\left(1\right)\)
\(n_{Cl_2}=\dfrac{21.84}{22.4}=0.975\left(mol\right)\)
\(Cu+Cl_2\underrightarrow{^{^{t^0}}}CuCl_2\)
\(Fe+\dfrac{3}{2}Cl_2\underrightarrow{^{^{t^0}}}FeCl_3\)
\(Al+\dfrac{3}{2}Cl_2\underrightarrow{^{^{t^0}}}AlCl_3\)
\(n_{Cl_2}=a+1.5b+1.5c=0.975\left(mol\right)\left(2\right)\)
\(n_{hh}=ka+kb+kc=0.25\left(mol\right)\)
\(n_{H_2}=kb+k\cdot1.5c=0.2\left(mol\right)\)
\(\Leftrightarrow a-0.25b-0.875c=0\left(3\right)\)
\(\left(1\right),\left(2\right),\left(3\right):a=0.3,b=0.15,c=0.3\)
\(\%Cu=\dfrac{0.3\cdot64}{35.7}\cdot100\%=53.78\%\)
\(\%Fe=\dfrac{0.15\cdot56}{35.7}\cdot100\%=23.52\%\)
\(\text{%Al=22.7%}\)
dap an B nao ? lam gi co dap an B