Cho 11g hỗn hợp X gồm Al và Fe tác dụng với dung dịch HCl 2M tạo thành 8,96l khí (đktc)
a) Tính % khối lượng các chất có tronh hỗn hợp ban đầu
b) Tính V HCl cần dùng vừa đủ
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\(Fe\left(a\right)+2HCl-->FeCl_2+H_2\left(a\right)\)
\(2Al\left(b\right)+6HCl-->2AlCl_3+3H_2\left(\dfrac{3}{2}b\right)\)
Gọi a,b lần lượt là số mol của Fe và Al trong hh ban đầu
nH2= 8,96/22,4=0,4 mol
Ta có HPT:
\(\left\{{}\begin{matrix}56a+27b=11\\a+\dfrac{3}{2}b=0,4\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,1\\b=0,2\end{matrix}\right.\)
Đến đây thì dễ rồi bạn :)
a) PTHH: 2Al + 6HCl ----> 2AlCl3 + 3H2 (1)
Fe + 2HCl ----> FeCl2 + H2 (2)
n\(H_2\) = \(\dfrac{8,96}{22,4}=0,4\left(mol\right)\)
- Gọi số mol của Al là a (mol)
- Gọi số mol của Fe là b (mol)
Theo PTHH (1) : n\(H_{2\left(1\right)}\) = \(\dfrac{3}{2}n_{Al}\) = \(\dfrac{3}{2}a\left(mol\right)\)
Theo PTHH (2) : n\(H_{2\left(2\right)}\)= nFe = b (mol)
Từ đó ta có hệ:
27a + 56b = 11
\(\dfrac{3}{2}\)a + b = 0,4
Giải hệ ra ta được: a = 0,2 (mol), b = 0,1 (mol)
=> mAl = 0,2.27 = 5,4 (g)
mFe = 56.0,1 = 5,6 (g)
=> %mAl = \(\dfrac{5,4}{11}.100\%=49,09\%\)
%mFe = 100% - 49,09% = 50,91%
b) Theo PTHH : nHCl(1) = \(\dfrac{6}{2}n_{Al}=0,6\left(mol\right)\)
Theo PTHH: nHCl(2) = 2nFe = 0,2 (mol)
=> nHCl = nHCl(1) + nHCl(2) = 0,6+0,2=0,8 (mol)
=> VHCl = \(\dfrac{n}{C_M}=\dfrac{0,8}{2}=0,4\left(l\right)\)
\(n_{Al}=a\left(mol\right)\)
\(n_{Fe}=b\left(mol\right)\)
\(m=27a+56b=19.3\left(g\right)\left(1\right)\)
\(n_{H^+}=0.2\cdot2+0.2\cdot2.25\cdot2=1.3\left(mol\right)\)
\(2Al+6H^+\rightarrow2Al^{3+}+3H_2\)
\(Fe+2H^+\rightarrow Fe^{2+}+H_2\)
\(n_{H^+}=3a+2b=1.3\left(mol\right)\left(2\right)\)
\(\left(1\right),\left(2\right):a=0.3,b=0.2\)
\(\%Al=\dfrac{0.3\cdot27}{19.3}\cdot100\%=41.96\%\)
\(\%Fe=58.04\%\)
\(b.\)
\(n_{H_2}=\dfrac{1}{2}n_{H^+}=0.65\left(mol\right)\)
Bảo toàn khối lượng :
\(m_{Muối}=19.3+0.4\cdot36.5+0.45\cdot98-0.65\cdot2=76.7\left(g\right)\)
a.\(n_{H_2}=\dfrac{V_{H_2}}{22,4}=\dfrac{8,96}{22,4}=0,4mol\)
Gọi \(\left\{{}\begin{matrix}n_{Fe}=x\\n_{Zn}=y\end{matrix}\right.\)
\(Fe+2HCl\rightarrow FeCl_2+H_2\)
x x ( mol )
\(Zn+2HCl\rightarrow ZnCl_2+H_2\)
y y ( mol )
Ta có:
\(\left\{{}\begin{matrix}56x+65y=25,55\\x+y=0,4\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x=0,05\\y=0,35\end{matrix}\right.\)
\(\Rightarrow m_{Fe}=0,05.56=2,8g\)
\(\Rightarrow m_{Zn}=0,35.65=22,75g\)
\(\%m_{Fe}=\dfrac{2,8}{25,55}.100=10,95\%\)
\(\%m_{Zn}=100\%-10,95\%=89,05\%\)
b.\(n_{HCl}=2.0,05+2.0,35=0,8mol\)
\(C_M=\dfrac{n}{V}\Rightarrow V=\dfrac{n}{C_M}=\dfrac{0,8}{2}=0,4l\)
a, PT: \(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
\(Al_2O_3+6HCl\rightarrow2AlCl_3+3H_2O\)
Ta có: \(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
Theo PT: \(n_{Al}=\dfrac{2}{3}n_{H_2}=0,1\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{Al}=\dfrac{0,1.27}{5,25}.100\%\approx51,43\%\\\%m_{Al_2O_3}\approx48,57\%\end{matrix}\right.\)
b, \(n_{Al_2O_3}=\dfrac{5,25-0,1.27}{102}=0,025\left(mol\right)\)
Theo PT: \(n_{HCl}=3n_{Al}+6n_{Al_2O_3}=0,45\left(mol\right)\)
\(\Rightarrow m_{ddHCl}=\dfrac{0,45.36,5}{29,2\%}=56,25\left(g\right)\)
c, \(n_{H_2SO_4}=\dfrac{1}{2}n_{HCl}=0,225\left(mol\right)\)
\(\Rightarrow m_{ddH_2SO_4}=\dfrac{0,225.98}{19,6\%}=112,5\left(g\right)\)
2al+6hcl-> 2alcl3+ 3h2
fe+2hcl-> fecl2+h2
nh2=13,44/22,4=0,6 mol
27a+56b=16,5
1,5a+ b=0,6
a=0,3, b=0,15
%mal=0,3*27/16,5*100=49,09%
%mfe=50,9%
nhcl=3a+2b=1,2
Vdd hcl=1,2/2=0,6l
a/ Fe + 2HCl \(\rightarrow\) FeCl2 + H2
nH2 = \(\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
Theo PTHH: nH2 = nFe = 0,15 (mol) \(\Rightarrow m_{Fe}=0,15.56=8,4\left(g\right)\)
\(\Rightarrow m_{Cu}=11-8,4=2,6\left(g\right)\)
\(\Rightarrow\%m_{Fe}=\dfrac{8,4}{11}.100\%\approx76,4\%\)
\(\Rightarrow\%m_{Cu}=100-76,4\approx23,6\%\)
b/ Theo PTHH ta có: nHCl = 2nFe = 2.0,15 = 0,3 (mol)
\(\Rightarrow V_{ddHCl}=\dfrac{0,3}{2}=0,15\left(M\right)\)
c/ mHCl = 36,5 . 0,3 = 10,95(g)
\(\Rightarrow C\%_{HCl}=\dfrac{m_{HCl}}{m_{ddHCl}}.100\%=\dfrac{10,95}{200}.100\%=5,475\%\)
a, PT: \(Fe+2HCl\rightarrow FeCl_2+H_2\)
Ta có: \(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
Theo PT: \(n_{Fe}=n_{H_2}=0,15\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{Fe}=\dfrac{0,15.56}{11}.100\%\approx76,36\%\\\%m_{Cu}\approx23,64\%\end{matrix}\right.\)
b, Theo PT: \(n_{HCl}=2n_{H_2}=0,3\left(mol\right)\)
\(\Rightarrow V_{ddHCl}=\dfrac{0,3}{2}=0,15\left(l\right)\)
c, \(C\%_{HCl}=\dfrac{0,3.36,5}{200}.100\%=5,475\%\)
a)
Gọi số mol Mg, Al là a, b (mol)
=> 24a + 27b = 26,25 (1)
\(n_{H_2}=\dfrac{30,8}{22,4}=1,375\left(mol\right)\)
PTHH: Mg + 2HCl --> MgCl2 + H2
a-->2a--------->a------>a
2Al + 6HCl --> 2AlCl3 + 3H2
b---->3b------->b------>1,5b
=> a + 1,5b = 1,375 (2)
(1)(2) => a = 0,25 (mol); b = 0,75 (mol)
=> \(\left\{{}\begin{matrix}\%m_{Mg}=\dfrac{0,25.24}{26,25}.100\%=22,857\%\\\%m_{Al}=\dfrac{0,75.27}{26,25}.100\%=77,143\%\end{matrix}\right.\)
b)
nHCl = 2a + 3b = 2,75 (mol)
=> mHCl = 2,75.36,5 = 100,375 (g)
=> \(m_{dd.HCl}=\dfrac{100,375.100}{10}=1003,75\left(g\right)\)
c)
mdd sau pư = 1003,75 + 26,25 - 1,375.2 = 1027,25 (g)
\(\left\{{}\begin{matrix}C\%_{MgCl_2}=\dfrac{0,25.95}{1027,25}.100\%=2,312\%\\C\%_{AlCl_3}=\dfrac{0,75.133,5}{1027,25}.100\%=9,747\%\end{matrix}\right.\)
\(a,n_{Al}=x(mol);n_{Fe}=y(mol)\\ \Rightarrow 27x+56y=11(1)\\ n_{H_2}=\dfrac{8,96}{22,4}=0,4(mol)\\ 2Al+6HCl\to 2AlCl_3+3H_2\\ Fe+2HCl\to FeCl_2+H_2\\ \Rightarrow 1,5x+y=0,4(2)\\ (1)(2)\Rightarrow x=0,2(mol);y=0,1(mol)\\ \Rightarrow \begin{cases} \%_{Al}=\dfrac{0,2.27}{11}.100\%=49,09\%\\ \%_{Fe}=100\%-49,09\%=50,91\% \end{cases}\\ b,\Sigma n_{HCl}=3x+2y=0,8(mol)\\ \Rightarrow V_{dd_{HCl}}=\dfrac{0,8}{2}=0,4(l)\)