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PTHH: 2Al + 3H2SO4 ---> Al2(SO4)3 + 3H2
Ag không phản ứng với HCl vì trong dãy hoạt động hóa học thì Ag đứng sau H.
=> \(n_{H_2}=\frac{13,44}{22,4}=0,6\) (mol)
Theo PTHH: \(n_{Al}=\frac{2}{3}n_{H_2}=\frac{2}{3}.0,6=0,4\) (mol)
=> mAl = 0,4.27 = 10,8 (g)
=> mAg = 12 - 10,8 = 1,2(g)
a)PTHH: 2Al + 3H2SO4 --> Al2(SO4)3 + 3H2
(mol) 2 3 1 3
(mol) 0,4 <-- 0,6 <-- 0,2 <-- 0,6
nH2= V/22,4 = 13,44/22,4 = 0,6(mol)
mAl=n.M= 0,4.27 = 10,8(g)
%mAl = mAl/mhh.100% = 10,8/12.100% = 90%
b) mH2SO4 = n.M = 0,6.98=58,8(g)
mddH2SO4 = 58,8.100%/7,35 = 800(g)
VddH2SO4=mdd/D = 800/1,025= 780,48(ml)
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\(a.PTHH:\)
\(Mg+2HCl--->MgCl_2+H_2\uparrow\left(1\right)\)
\(MgO+2HCl--->MgCl_2+H_2O\left(2\right)\)
b. ta có: \(n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
Theo PT(1): \(n_{Mg}=n_{H_2}=0,2\left(mol\right)\)
\(\Rightarrow m_{MgO}=12-0,2.24=7,2\left(g\right)\)
\(\Rightarrow\%_{MgO}=\dfrac{7,2}{12}.100\%=60\%\)
c. Ta có: \(n_{hh}=0,2+\dfrac{7,2}{40}=0,38\left(mol\right)\)
Theo PT(1,2): \(n_{HCl}=2.n_{hh}=2.0,38=0,76\left(mol\right)\)
\(\Rightarrow m_{HCl}=0,76.36,5=27,74\left(g\right)\)
\(\Rightarrow m_{dd_{HCl}}=138,7\left(g\right)\)
\(\Rightarrow V_{dd_{HCl}}=126\left(ml\right)\)
\(a.Mg+2HCl\rightarrow MgCl_2+H_2\\ MgO+2HCl\rightarrow MgCl_2+H_2O\\ b.n_{H_2}=n_{Mg}=0,3\left(mol\right)\\ \Rightarrow\%m_{Mg}=\dfrac{0,3.24}{15,6}.100=48,15\%;\%m_{MgO}=53,85\%\)
a) Đặt: nMg=x(mol); nZnO=y(mol)
nH2SO4= 0,2(mol)
PTHH: Mg + H2SO4 -> MgSO4 + H2
x___________x____x_______x(mol)
ZnO + H2SO4 -> ZnSO4 + H2O
y____y______y(mol)
Ta có:
\(\left\{{}\begin{matrix}24x+81y=12,9\\22,4x=4,48\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0,2\\y=0,1\end{matrix}\right.\)
mMg=0,2.24=4,8(g)
%mMg=(4,8/12,9).100=37,209%
=>%mZnO=62,791%
b) nH2SO4=x+y=0,3(mol)
=> \(C\%ddH2SO4=\dfrac{0,3.98}{120}.100=24,5\%\)
\(n_{H_2}=\dfrac{3,36}{22,4}0,15(mol)\\ a,PTHH:Fe+H_2SO_4\to FeSO_4+H_2\\ b,n_{Fe}=n_{H_2}=0,15(mol)\\ \Rightarrow \%_{Fe}=\dfrac{0,15.56}{14,8}.100\%=56,76\%\\ \Rightarrow \%_{Cu}=100\%-56,76\%=43,24\%\\ c,n_{H_2SO_4}=0,15(mol)\\ \Rightarrow m_{dd_{H_2SO_4}}=\dfrac{0,15.98}{20\%}=73,5(g)\\ \Rightarrow V_{dd_{H_2SO_4}}=\dfrac{73,5}{1,4}=52,5(l)\)
\(a)Zn+H_2SO_4\rightarrow ZnSO_4+H_2\\ Fe+H_2SO_4\rightarrow FeSO_4+H_2\\ n_{H_2}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\\ b)Đặt:n_{Zn}=x\left(mol\right);n_{Fe}=y\left(mol\right)\\ Tacó:\left\{{}\begin{matrix}65x+56y=12,1\\x+y=0,2\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}x=0,1\\y=0,1\end{matrix}\right.\\ \Rightarrow m_{Fe}=0,1.56=5,6\left(g\right);m_{Zn}=0,1.65=6,5\left(g\right)\\ c)n_{H_2SO_4}=n_{H_2}=0,2\left(mol\right)\\ \Rightarrow C\%_{H_2SO_{\text{ 4}}}=\dfrac{0,2.98}{196}.100=10\%\)
PTHH: \(Zn+2HCl\rightarrow ZnCl_2+H_2\uparrow\)
Ta có: \(n_{H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{Zn}=0,3\left(mol\right)=n_{ZnCl_2}\\n_{HCl}=0,6\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}\%m_{Zn}=\dfrac{0.3\cdot65}{35,5}\cdot100\%\approx54,93\%\\\%m_{Cu}=45,07\%\\C\%_{HCl}=\dfrac{0,6\cdot36,5}{500}\cdot100\%=4,38\%\\m_{ZnCl_2}=0,3\cdot136=40,8\left(g\right)\end{matrix}\right.\)
Mặt khác: \(\left\{{}\begin{matrix}m_{Cu}=35,5-0,3\cdot65=16\left(g\right)\\m_{H_2}=0,3\cdot2=0,6\left(g\right)\end{matrix}\right.\)
\(\Rightarrow m_{dd}=m_{KL}+m_{ddHCl}-m_{Cu}-m_{H_2}=518,9\left(g\right)\)
\(\Rightarrow C\%_{ZnCl_2}=\dfrac{40,8}{518,9}\cdot100\%\approx7,86\%\)
\(n_k=n_{H_2}=0,125\left(mol\right)\)
a,b, \(PTHH:Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
.............0,125...0,125....................0,125...
\(\Rightarrow m_{Fe}=7\left(g\right)\)
Do Cu không phản ứng với H2SO4 .
\(\Rightarrow m_{Cu}=m_{hh}-m_{Fe}=10-7=3\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}\%Fe=70\%\\\%Cu=30\%\end{matrix}\right.\)
c, Có : \(m_{dd}=m_{Fe}+m_{ddH_2SO_4}-m_{H_2}=206,75\left(g\right)\)
\(\Rightarrow C\%=\dfrac{m_{H_2SO_4}}{m_{dd}}.100\%\approx5,925\%\)