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PTHH: \(Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)
\(FeO+2HCl\rightarrow FeCl_2+H_2O\)
Ta có: \(n_{H_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)=n_{Fe}\) \(\Rightarrow n_{FeO}=\dfrac{12,8-0,1\cdot56}{72}=0,1\left(mol\right)\)
Theo các PTHH: \(\Sigma n_{HCl}=2n_{Fe}+2n_{FeO}=0,4\left(mol\right)\)
\(\Rightarrow V_{HCl}=\dfrac{0,4}{0,1}=4\left(l\right)\)
\(n_{H_2}=\dfrac{2,24}{22,4}=0,1mol\)
Fe + 2HCl => FeCl2 + H2
0,1 0,2 0,1
=> FeO = \(\dfrac{12,8-0,1.56}{72}=0,1\left(mol\right)\)
FeO + 2HCl => FeCl2 + H2O
0,1 0,2
VHCl = 0,2 . 22,4 = 4,48 lít
\(n_{O_2}=\dfrac{22,12-21,16}{32}=0,03\left(mol\right)\)
\(n_{KMnO_4}=\dfrac{22,12}{158}=0,14\left(mol\right)\)
Mn+7 + 5e --> Mn+2
0,14-->0,7
2O-2 - 4e --> O20
0,12<--0,03
2Cl- - 2e --> Cl20
2a<---a
Bảo toàn e: 2a + 0,12 = 0,7
=> a = 0,29 (mol)
=> VCl2 = 0,29.22,4 = 6,496 (l)
Bảo toàn nguyên tố: \(\left\{{}\begin{matrix}n_{Fe}=n_{FeCl_3}=a\left(mol\right)\\n_{Cu}=n_{CuCl_2}=b\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}56a+64b=12\\162,5a+135b=29,75\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}a=0,1\\b=0,1\end{matrix}\right.\)
\(\Rightarrow\%m_{Fe}=\dfrac{0,1\cdot56}{12}\cdot100\%\approx46,67\%\)
\(2A+2aHCl\rightarrow2ACl_a+aH_2\)
\(TheoPTHH:n_{H_2}=\dfrac{an_A}{2}=0,5an_A=0,5.a.\dfrac{1,17}{A}=\dfrac{V}{22,4}=0,015\)
\(\Rightarrow\dfrac{a}{A}=\dfrac{1}{39}\)
\(\Rightarrow\) A là Kali ( K ).
\(\Rightarrow n_{HCl}=2n_{H_2}=0,03\left(mol\right)\)
\(\Rightarrow V_{HCl}=\dfrac{n}{C_M}=\dfrac{0,03}{1,2}=0,025\left(l\right)=25\left(ml\right)\)
a) Ta có: \(n_{H_2}=\dfrac{15,68}{22,4}=0,7\left(mol\right)\)
Gọi a và b lần lượt là số mol của Al và Zn
Bảo toàn mol e: \(3a+2b=1,4\)
Mà \(27a+65b=31,4\)
\(\Rightarrow\left\{{}\begin{matrix}a=0,2\\b=0,4\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}\%m_{Al}=\dfrac{0,2\cdot27}{31,4}\cdot100\%\approx17,2\%\\\%m_{Zn}=82,8\%\end{matrix}\right.\)
b) Bảo toàn nguyên tố: \(n_{HCl}=2n_{H_2}=1,4mol\)
\(\Rightarrow V_{HCl}=\dfrac{1,4}{2}=0,7\left(l\right)=700\left(ml\right)\)
Đặt :
nAl = a mol
nZn = b mol
mB = 27a + 65b = 31.4 (g) (1)
2Al + 6HCl => 2AlCl3 + 3H2
a___________________1.5a
Zn + 2HCl => ZnCl2 + H2
b__________________b
nH2 = 1.5a + b = 15.68/22.4 = 0.7 (mol) (2)
(1) , (2) :
a = 0.2
b = 0.4
%Al = 5.4/31.4 * 100% = 17.19%
%Zn = 100 - 17.19 = 82.81%
nHCl = 2nH2 = 0.7*2 = 1.4 (mol)
Vdd HCl = 1.4 / 2 = 0.7 (l)
Ta có: \(n_{H_2}=\dfrac{15,68}{22,4}=0,7\left(mol\right)\)
Gọi a và b lần lượt là số mol của Al và Fe
Bảo toàn mol e: \(3a+2b=1,4\)
Mà \(27a+56b=27,8\)
\(\Rightarrow\left\{{}\begin{matrix}a=0,2\\b=0,4\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}\%m_{Al}=\dfrac{0,2\cdot27}{27,8}\cdot100\approx19,42\%\\\%m_{Fe}=80,58\%\end{matrix}\right.\)
Đặt :
nAl = a mol
nFe = b mol
mB = 27a + 56b = 27.8 (g) (1)
2Al + 6HCl => 2AlCl3 + 3H2
a___________________1.5a
Fe + 2HCl => FeCl2 + H2
b__________________b
nH2 = 1.5a + b = 15.68/22.4 = 0.7 (mol) (2)
(1) , (2) :
a = 0.2
b = 0.4
%Al = 5.4/27.8 * 100% = 19.42%
%Fe = 100 - 19.42 = 80.58%
PTHH: \(CaO+2HCl\rightarrow CaCl_2+H_2O\) (1)
\(CaCO_3+2HCl\rightarrow CaCl_2+H_2O+CO_2\uparrow\) (2)
a) Ta có: \(\left\{{}\begin{matrix}\Sigma n_{CaCl_2}=\dfrac{33,3}{111}=0,3\left(mol\right)\\n_{CO_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}n_{CaO}=0,1mol\\n_{CaCO_3}=0,2mol\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{CaO}=0,1\cdot56=5,6\left(g\right)\\m_{CaCO_3}=0,2\cdot100=20\left(g\right)\end{matrix}\right.\)
\(\Rightarrow m_{hh}=20+5,6=25,6\left(g\right)\)
b) Theo các PTHH: \(\left\{{}\begin{matrix}n_{HCl\left(1\right)}=0,2mol\\n_{HCl\left(2\right)}=0,4mol\end{matrix}\right.\)
\(\Rightarrow\Sigma n_{HCl}=0,6mol\) \(\Rightarrow C_{M_{HCl}}=\dfrac{0,6}{0,3}=2\left(M\right)\)
PT: \(CaO+2HCl\rightarrow CaCl_2+H_2O\) (1)
\(CaCO_3+2HCl\rightarrow CaCl_2+H_2O+CO_2\) (2)
a, Ta có: \(n_{CO_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
\(\Sigma n_{CaCl_2}=\dfrac{33,3}{111}=0,3\left(mol\right)\)
Theo PT (2): \(n_{CaCl_2}=n_{CO_2}=0,2\left(mol\right)\)
\(\Rightarrow n_{CaCl_2\left(1\right)}=0,3-0,2=0,1\left(mol\right)\)
Theo PT (1): \(n_{CaO}=n_{CaCl_2}=0,1\left(mol\right)\)
Theo PT (2): \(n_{CaCO_3}=n_{CO_2}=0,2\left(mol\right)\)
\(\Rightarrow m_A=m_{CaO}+m_{CaCO_3}=0,1.56+0,2.100=25,6\left(g\right)\)
b, Theo PT (1) + (2): \(\Sigma n_{HCl}=2n_{CaO}+2n_{CaCO_3}=0,6\left(mol\right)\)
\(\Rightarrow C_{M_{ddHCl}}=\dfrac{0,6}{0,3}=2M\)
Bạn tham khảo nhé!
PTHH: \(2KMnO_4+16HCl_{\left(đ\right)}\rightarrow2KCl+2MnCl_2+5Cl_2\uparrow+8H_2O\)
Ta có: \(n_{KMnO_4}=\dfrac{14,2}{158}=\dfrac{71}{790}\left(mol\right)\)
\(\Rightarrow n_{Cl_2}=\dfrac{71}{316}\left(mol\right)\) \(\Rightarrow V_{Cl_2}=\dfrac{71}{316}\cdot22,4\approx5,03\left(l\right)\)