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1. \(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
2. Gọi: \(\left\{{}\begin{matrix}n_{Zn}=x\left(mol\right)\\n_{Al}=y\left(mol\right)\end{matrix}\right.\) ⇒ 65x + 27y = 17,7 (1)
Theo PT: \(n_{H_2}=n_{Zn}+\dfrac{3}{2}n_{Al}=x+\dfrac{3}{2}y=\dfrac{5,6}{22,4}=0,25\left(mol\right)\left(2\right)\)
Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}x=\dfrac{66}{235}\\y=-\dfrac{29}{1410}\end{matrix}\right.\)
Tới đây thì ra số mol âm, bạn xem lại đề nhé.
1. \(Zn+H_2SO_4\rightarrow ZnSO_4+H_2\)
\(2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\)
2. Gọi: \(\left\{{}\begin{matrix}n_{Zn}=x\left(mol\right)\\n_{Al}=y\left(mol\right)\end{matrix}\right.\) ⇒ 65x + 27y = 9,2 (1)
Theo PT: \(n_{H_2}=n_{Zn}+\dfrac{3}{2}n_{Al}=x+\dfrac{3}{2}y=\dfrac{5,6}{22,4}=0,25\left(mol\right)\left(2\right)\)
Từ (1) và (2) ⇒ x = y = 0,1 (mol)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{Zn}=\dfrac{0,1.65}{9,2}.100\%\approx70,65\%\\\%m_{Al}\approx29,35\%\end{matrix}\right.\)
3. Theo PT: \(\left\{{}\begin{matrix}n_{ZnSO_4}=n_{Zn}=0,1\left(mol\right)\\n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{2}n_{Al}=0,05\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}m_{ZnSO_4}=0,1.160=16\left(g\right)\\m_{Al_2\left(SO_4\right)_3}=0,05.342=17,1\left(g\right)\end{matrix}\right.\)
\(a.2Al+6HCl->2AlCl_3+3H_2\\ Mg+2HCl->MgCl_2+H_2\\ b.n_{Al}=a,n_{Mg}=b\\ 27a+24b=7,5\left(I\right)\\ 1,5a+b=\dfrac{7,84}{22,4}=0,35\left(II\right)\\ a=0,1;b=0,2\\ \%m_{Al}=\dfrac{27\cdot0,1}{7,5}\cdot100\%=36\%\\ \%m_{Mg}=64\%\\ c.m_{HCl}=36,5\left(0,1\cdot3+0,2\cdot2\right)=18,25g\\ d.m_{ddsau}=7,5+\dfrac{18,25}{14,6:100}-0,35\cdot2=131,8g\\ C\%\left(AlCl_3\right)=\dfrac{133,5\cdot0,1}{131,8}\cdot100\%=10,1\%\\ C\%\left(MgCl_2\right)=\dfrac{95\cdot0,2}{131,8}\cdot100\%=14,4\%\)
a)
Mg + 2HCl --> MgCl2 + H2
b)
\(n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
PTHH: Mg + 2HCl --> MgCl2 + H2
0,3<-----------------0,3
=> mMg = 0,3.24 = 7,2 (g)
=> mAg = 10,4 - 7,2 = 3,2 (g)
c) \(\left\{{}\begin{matrix}\%m_{Mg}=\dfrac{7,2}{10,4}.100\%=69,23\%\\\%m_{Ag}=\dfrac{3,2}{10,4}.100\%=30,77\%\end{matrix}\right.\)
\(n_{H_2}=\dfrac{0,448}{22,4}=0,02\left(mol\right)\\ a,PTHH:2Al+6HCl\rightarrow2AlCl_3+3H_2\\ n_{Al}=\dfrac{2}{3}.0,02=\dfrac{1}{75}\left(mol\right)\\ b,\%m_{Al}=\dfrac{\dfrac{1}{75}.27}{30}.100=1,2\%\Rightarrow\%m_{Cu}=100\%-1,2\%=98,8\%\)
Ta có nH2 = \(\dfrac{5,6}{22,4}\) = 0,25 ( mol )
2Al + 6HCl \(\rightarrow\) 2AlCl3 + 3H2
x...........3x............x............1,5x
Fe + 2HCl \(\rightarrow\) FeCl2 + H2
y.......2y............y............y
=> \(\left\{{}\begin{matrix}27x+56y=8,3\\1,5x+y=0,25\end{matrix}\right.\)
=> \(\left\{{}\begin{matrix}x=0,1\\y=0,1\end{matrix}\right.\)
=> mAl = 27 . 0,1 = 2,7 ( gam )
=> %mAl = \(\dfrac{2,7}{8,3}\) . 100 \(\approx\) 32,5 %
=> %mFe = 100 - 32,5 = 67,5 %
PTHH :
Fe(x) + 2HCl ----> FeCl2 + H2(x)
2Al(y) + 6HCl -----> 2AlCl3 + 3H2(1,5y)
nH2 = 5,6 : 22,4 = 0,25 (mol)
Đặt số mol của Fe là x ; số mol của Al là y
Ta có :
56x + 27y = 8,3 (*)
x + 1,5y = 0,25 => x = 0,25 - 1,5y (**)
Thay (**) vào (*) ta có :
56(0,25 - 1,5y) + 27y = 8,3
=> 14 - 84y + 27y = 8,3
=> 14 - 57y = 8,3
=> 57y = 5,7
=> y = 0,1 (mol)
=> x = 0,25 - 1,5 . 0,1 = 0,1 (mol)
=> mFe = 0,1 . 56 = 5,6 (g)
=> mAl = 0,1 . 27 = 2,7 (g)
=> %mFe = 5,6 . 100% : 8,3 = 67,5%
=> %mAl = 100% - 67,5% = 32,5%
$n_{Al} = a(mol) ; n_{Fe} = b(mol) \Rightarrow 27a + 56b = 8,3(1)$
$2Al + 6HCl \to 2AlCl_3 + 3H_2$
$Fe + 2HCl \to FeCl_2 + H_2$
$n_{H_2} = 1,5a + b = \dfrac{5,6}{22,4} = 0,25(2)$
Từ (1)(2) suy ra a = b = 0,1
$\%m_{Al} = \dfrac{0,1.27}{8,3}.100\% = 32,53\%$
$\%m_{Fe} = 100\% - 32,53\% = 67,47\%$
a, Cu không tác dụng với dd HCl.
PT: \(Zn+2HCl\rightarrow ZnCl_2+H_2\)
b, Ta có: \(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
Theo PT: \(n_{Zn}=n_{H_2}=0,2\left(mol\right)\)
\(\Rightarrow m_{Zn}=0,2.65=13\left(g\right)\)
\(\Rightarrow m_{Cu}=19,4-13=6,4\left(g\right)\)
c, Ta có: \(\left\{{}\begin{matrix}\%m_{Zn}=\dfrac{13}{19,4}.100\%\approx67,01\%\\\%m_{Cu}\approx32,99\%\end{matrix}\right.\)
Bạn tham khảo nhé!
\(n_{H_2}=\dfrac{5,6}{22,4}=0,25(mol)\\ a,PTHH:Fe+2HCl\to FeCl_2+H_2\\ 2Al+6HCl\to 2AlCl_3+3H_2\)
\(b,\) Đặt \(n_{Fe}=x(mol);n_{Al}=y(mol)\)
\(\Rightarrow 56x+27y=8,3(1)\)
Theo PTHH: \(x+1,5y=0,25(2)\)
\((1)(2)\Rightarrow x=y=0,1(mol)\\ \Rightarrow \%_{Fe}=\dfrac{0,1.56}{8,3}.100\%=67,47\%\\ \%_{Al}=100\%-67,47\%=32,53\%\)