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a)
$X + 2HCl \to XCl_2 + H_2$
$2Y + 6HCl \to 2YCl_3 + 3H_2$
$n_{HCl} = \dfrac{47,45}{36,5} = 1,3(mol) \Rightarrow n_{H_2} = \dfrac{1}{2}n_{HCl} = 0,65(mol)$
$\Rightarrow V_{H_2} = 0,65.22,4 = 14,56(lít)$
b) Bảo toàn khối lượng : $m_{muối} = 12,9 + 1,3.36,5 - 0,65.2 = 59,05(gam)$
c) Gọi $n_X = a(mol) \Rightarrow n_{Al} = 1,5a(mol)$
Theo PTHH : $n_{H_2} = a + 1,5a.\dfrac{3}{2} = 0,65(mol) \Rightarrow a = 0,2$
$\Rightarrow m_{hh} = 0,2.X + 0,2.1,5.27 = 12,9$
$\Rightarrow X = 24(Magie)$
Gọi \(\left\{{}\begin{matrix}n_{Al}=x\left(mol\right)\\n_{Fe}=y\left(mol\right)\end{matrix}\right.\)
\(n_{H_2}=\dfrac{4,48}{22,4}=0,2mol\)
\(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
\(Fe+2HCl\rightarrow FeCl_2+H_2\)
Theo pt: \(\Rightarrow\left\{{}\begin{matrix}3x+y=0,2\\27x+56y=5,5\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=\dfrac{19}{470}\\y=\dfrac{37}{470}\end{matrix}\right.\)
\(\%m_{Al}=\dfrac{\dfrac{19}{470}\cdot27}{5,5}\cdot100\%=19,84\%\)
\(\%m_{Fe}=100\%-19,84\%=80,16\%\)
PTHH: \(Mg+H_2SO_4\rightarrow MgSO_4+H_2\)
a______________________a (mol)
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
b_____________________b (mol)
Ta lập HPT: \(\left\{{}\begin{matrix}24a+56b=10,4\\a+b=\dfrac{6,72}{22,4}=0,3\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}a=0,2\\b=0,1\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{Mg}=\dfrac{0,2\cdot24}{10,4}\cdot100\%\approx46,15\%\\m_{ddH_2SO_4}=\dfrac{\left(0,2+0,1\right)\cdot98}{10\%}=294\left(g\right)\end{matrix}\right.\)
a) PTHH: \(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)
b) Ta có: \(n_{HCl\left(p/ứ\right)}=2n_{Mg}=2\cdot\dfrac{7,2}{24}=0,6\left(mol\right)\)
\(\Rightarrow n_{HCl}=0,6\cdot110\%=0,66\left(mol\right)\) \(\Rightarrow m_{ddHCl}=\dfrac{0,66\cdot36,5}{7,3\%}=330\left(g\right)\)
c) PTHH: \(Fe_2O_3+3H_2\xrightarrow[]{t^o}2Fe+3H_2O\)
Theo PTHH: \(n_{Fe}=\dfrac{2}{3}n_{H_2}=\dfrac{2}{3}n_{Mg}=0,2\left(mol\right)\) \(\Rightarrow m_{Fe}=0,2\cdot56=11,2\left(g\right)\)
\(n_{Fe} = a(mol) ; n_M = b(mol)\\ \Rightarrow 56a + Mb = 12\)
\(Fe + 2HCl \to FeCl_2 + H_2\\ M + 2HCl \to MCl_2 + H_2\\ n_{H_2} = a + b = \dfrac{4,48}{22,4} = 0,2(mol)\\ \Rightarrow a = 0,2 - b ( 0< b < 0,2)\)
Suy ra:
56(0,2 - b) + Mb = 12
\(\Rightarrow M = \dfrac{0,8 + 56b}{b}\)
Vì 0 < b < 0,12
Nên M > 62,67(1)
Mặt khác,
\(n_M > \dfrac{1}{2}n_{HCl} = 0,35\\ \Rightarrow M < \dfrac{23,8}{0,35} = 68(2)\)
Từ (1)(2) suy ra: 62,67 < M < 68
Do đó, M = 65(Zn) thì thỏa mãn
Vậy M là Zn(Kẽm)
Gọi \(\left\{{}\begin{matrix}n_{Fe}=x\left(mol\right)\\n_{Ca}=y\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow56x+40y=10,4\left(1\right)\)
\(n_{HCl}=\dfrac{25,55}{36,5}=0,7mol\)
\(Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)
\(Ca+2HCl\rightarrow CaCl_2+H_2\uparrow\)
\(\Rightarrow2x+2y=0,7\left(2\right)\)
Tư (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}x=-0,225mol\\y=0,575mol\end{matrix}\right.\)
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