Cho 2,7g Al phản ứng hoàn toàn với dd HCl 1mol a. Viết phương trình phản ứng b.tính thể tích khí H2 thu được ở dktc c.tính dd HCl 1mol đã dùng
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Bài 1 :
\(a) Fe_2O_3 + 3H_2 \xrightarrow{t^o}2Fe + 3H_2O\\ b) n_{Fe_2O_3} = \dfrac{80}{160}= 0,5(mol)\\ n_{H_2} = 3n_{Fe_2O_3} = 1,5(mol)\\ \Rightarrow V_{H_2} = 1,5.22,4 = 33,6(lít)\\ n_{Fe} = 2n_{Fe_2O_3} = 1(mol)\\ m_{Fe} = 1.56 = 56(gam)\)
Bài 2 :
\(a) Fe + 2HCl \to FeCl_2 + H_2\\ n_{H_2} = n_{Fe} =\dfrac{5,6}{56} = 0,1(mol)\\ V_{H_2} = 0,1.22,4 = 2,24(lít)\\ n_{HCl} =2 n_{Fe} = 0,2(mol)\\ m_{HCl} = 0,2.36,5 = 7,3(gam)\)
a) PTHH: \(Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)
b+c) Ta có: \(n_{Fe}=\dfrac{16,8}{56}=0,3\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{H_2}=0,3\left(mol\right)\\n_{HCl}=0,6\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{HCl}=0,6\cdot36,5=21,9\left(g\right)\\V_{H_2}=0,3\cdot22,4=6,72\left(l\right)\end{matrix}\right.\)
d) PTHH: \(NaOH+HCl\rightarrow NaCl+H_2O\)
Ta có: \(\left\{{}\begin{matrix}n_{HCl}=0,6\left(mol\right)\\n_{NaOH}=\dfrac{20}{40}=0,5\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\) HCl còn dư, NaOH p/ứ hết
\(\Rightarrow\) Dung dịch sau p/ứ làm quỳ tím hóa đỏ
Theo PTHH: \(\left\{{}\begin{matrix}n_{NaCl}=0,5\left(mol\right)\\n_{HCl\left(dư\right)}=0,1\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{NaCl}=0,5\cdot58,5=29,25\left(g\right)\\m_{HCl\left(dư\right)}=0,1\cdot36,5=3,65\left(g\right)\end{matrix}\right.\)
Mặt khác: \(m_{dd}=m_{ddHCl}+m_{NaOH}=\dfrac{0,6\cdot36,5}{5\%}+20=458\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{NaCl}=\dfrac{29,25}{458}\cdot100\%\approx6,39\%\\C\%_{HCl\left(dư\right)}=\dfrac{3,65}{458}\cdot100\%\approx0,8\%\end{matrix}\right.\)
\(n_{Zn}=\dfrac{1,3}{65}=0,02\left(mol\right)\)
PTHH :
\(Zn+2HCl\rightarrow ZnCl_2+H_2\uparrow\)
0,02 0,04 0,02 0,02
\(V_{H_2}=0,02.22,4=0,448\left(l\right)\)
\(C_{M_{HCl}}=\dfrac{0,04}{4}=0,01M\)
b, \(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)
0,02 0,02
\(m_{Cu}=0,02.64=1,28\left(g\right)\)
\(m_{H_2SO_4}=\dfrac{200.9,8}{100}=19,6\left(g\right)\)
\(n_{H_2SO_4}=\dfrac{19,6}{98}=0,2\left(mol\right)\)
PTHH :
\(X+H_2SO_4\rightarrow XSO_4+H_2\)
0,2 0,2 0,2 0,2
\(M_X=\dfrac{8}{0,2}=40\left(dvC\right)\)
-> Canxi
\(b,V_{H_2}=0,2.22,4=4,48\left(l\right)\)
\(c,m_{CaSO_4}=0,2.136=27,2\left(g\right)\)
\(m_{ddCaSO_4}=8+200-\left(0,2.2\right)=207,6\left(g\right)\)
\(C\%=\dfrac{27,2}{207,6}.100\%\approx13,1\%\)
Gọi \(\left\{{}\begin{matrix}n_{Al}=a\left(mol\right)\\n_{Fe}=b\left(mol\right)\end{matrix}\right.\)
\(n_{HCl}=0,1.1,2=0,12\left(mol\right)\\ n_{H_2}=0,05\left(mol\right)\)
PTHH:
2Al + 6HCl ---> 2AlCl3 + 3H2
a 3a a 1,5a
Fe + 2HCl ---> FeCl2 + H2
b 2b b b
Hệ pt \(\left\{{}\begin{matrix}27a+56b=1,66\\1,5a+b=0,05\end{matrix}\right.\Leftrightarrow a=b=0,02\left(mol\right)\)
\(\rightarrow\left\{{}\begin{matrix}m_{Al}=0,02.27=0,54\left(g\right)\\m_{Fe}=0,02.56=1,12\left(g\right)\end{matrix}\right.\)
\(\rightarrow\left\{{}\begin{matrix}C_{M\left(AlCl_3\right)}=\dfrac{0,02}{0,1}=0,2M\\C_{M\left(FeCl_2\right)}=\dfrac{0,02}{0,1}=0,2M\\C_{M\left(HCl.dư\right)}=\dfrac{0,12-0,02.3-0,02.2}{0,1}=0,2M\end{matrix}\right.\)
\(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
\(n_{Al}=\dfrac{2.7}{27}=0.1\left(mol\right)\)
\(\Leftrightarrow n_{AlCl_3}=0.1\left(mol\right)\)
\(\Leftrightarrow n_{HCl}=0.3\left(mol\right)\)
\(\Leftrightarrow n_{H_2}=0.6\left(mol\right)\)
\(V=0.6\cdot22.4=13.84\left(lít\right)\)
Ta có: \(n_{HCl}=\dfrac{\dfrac{3,65\%.600}{100\%}}{36,5}=0,6\left(mol\right)\)
\(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\)
\(PTHH:2Al+6HCl--->2AlCl_3+3H_2\uparrow\)
Ta thấy: \(\dfrac{0,1}{2}< \dfrac{0,6}{6}\)
Vậy HCl dư, Al hết
Theo PT: \(n_{H_2}=\dfrac{3}{2}.n_{Al}=\dfrac{3}{2}.0,1=0,15\left(mol\right)\)
\(\Rightarrow V=V_{H_2}=0,15.22,4=3,36\left(lít\right)\)
Có lẽ đề cho dd HCl 1M (1 mol/l) chứ bạn nhỉ?
a, PT: \(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
b, \(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\)
Theo PT: \(n_{H_2}=\dfrac{3}{2}n_{Al}=0,15\left(mol\right)\Rightarrow V_{H_2}=0,15.22,4=3,36\left(l\right)\)
c, \(n_{HCl}=3n_{Al}=0,3\left(mol\right)\Rightarrow V_{ddHCl}=\dfrac{0,3}{1}=0,3\left(l\right)\)