Cho 2,8g Fe tác dụng với H2SO4 loãng vừa đủ tạo thành muối và V khí bay ra.
a) Tính V(l) khí
b) Dẫn V(l) khí trên tác dụng với CuO tạo thành m(g) rắn. Tính khối lượng CuO và khối lượng m(g) rắn
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\(n_{Fe}=\dfrac{22,4}{56}=0,4\) (mol) (1)
Phương trình hóa học :
Fe + 2HCl ---> FeCl2 + H2 (2)
Từ (1) và (2) ta có \(n_{FeCl_2}=n_{H_2}=0,4\) (mol) ; \(n_{HCl}=0,8\left(mol\right)\)
b) => \(m_{\text{muối}}=0,4.\left(56+35,5.2\right)=50.8\left(g\right)\)
c) \(V_{\text{khí}}=0,4.22,4=8,96\left(l\right)\)
d) \(m_{HCl}=0,8.36.5=29,2\left(g\right)\)
\(\Rightarrow C\%=\dfrac{29,2}{200}.100\%=14,6\%\)
\(Fe+2HCl\rightarrow FeCl_2+H_2\\ n_{Fe}=\dfrac{5,6}{56}=0,1\left(mol\right)\\ n_{H_2}=n_{Fe}=0,1\left(mol\right)\\ n_{CuO}=\dfrac{16}{80}=0,2\left(mol\right)\\ CuO+H_2-^{t^o}\text{ }\rightarrow Cu+H_2O\\ Lậptỉlệ:\dfrac{0,2}{1}>\dfrac{0,1}{1}\\ \Rightarrow CuOdư\\n_{H_2O}=n_{H_2}=0,1\left(mol\right)\\ BTKL:m_{CuO}+m_{H_2}=m_{cr}+m_{H_2O}\\ \Leftrightarrow16+0,1.2=m_{cr}+0,1.18\\ \Rightarrow m_{cr}=14,4\left(g\right)\)
a,\(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)
PTHH: 2Al + 3H2SO4 → Al2(SO4)3 + 3H2
Mol: 0,1 0,05 0,15
\(m_{Al}=0,1.27=2,7\left(g\right)\)
b,\(m_{Al_2\left(SO_4\right)_3}=0,05.342=17,1\left(mol\right)\)
a, \(n_{H_2}=\dfrac{8,96}{22,4}=0,4\left(mol\right)\)
PTHH: 2Al + 6HCl → 2AlCl3 + 3H2
Mol: x 1,5x
PTHH: Fe + 2HCl → FeCl2 + H2
Mol: y y
b, Ta có hpt: \(\left\{{}\begin{matrix}27x+56y=11\\1,5x+y=0,4\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0,2\\y=0,1\end{matrix}\right.\)
\(\Rightarrow\%m_{Al}=\dfrac{0,2.27.100\%}{11}=49,09\%\Rightarrow\%m_{Fe}=100\%-49,09\%=50,91\%\)
c, \(n_{CuO}=\dfrac{16}{80}=0,2\left(mol\right)\)
Ta có: \(\dfrac{0,2}{1}< \dfrac{0,4}{1}\) ⇒ CuO hết, H2 dư
PTHH: CuO + H2 → Cu + H2O
Mol: 0,2 0,2
\(m_{Cu}=0,2.64=12,8\left(g\right)\)
Gọi \(m_{Al}=a\left(g\right)\left(0< a< 11\right)\)
\(\rightarrow m_{Fe}=11-a\left(g\right)\)
\(\rightarrow\left\{{}\begin{matrix}n_{Al}=\dfrac{a}{27}\left(mol\right)\\n_{Fe}=\dfrac{11-a}{56}\left(mol\right)\end{matrix}\right.\)
PTHH:
\(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
\(\dfrac{a}{27}\) \(\dfrac{a}{18}\)
\(Fe+2HCl\rightarrow FeCl_2+H_2\)
\(\dfrac{11-a}{56}\) \(\dfrac{11-a}{56}\)
\(\rightarrow pt:\dfrac{a}{18}+\dfrac{11-a}{56}=0,4\\ \Leftrightarrow m_{Al}=a=5,4\left(g\right)\left(TM\right)\)
\(\rightarrow\left\{{}\begin{matrix}\%m_{Al}=\dfrac{5,4}{11}=49,1\%\\\%m_{Fe}=100\%-49,1\%=50,9\%\end{matrix}\right.\)
\(n_{CuO}=\dfrac{16}{80}=0,2\left(mol\right)\)
PTHH: \(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)
LTL: \(0,2< 0,4\rightarrow\) H2 dư
\(n_{Cu}=n_{CuO}=0,2\left(mol\right)\rightarrow m_{CuO}=0,2.64=12,8\left(g\right)\)
a) PTHH: \(2Al+6HCl\rightarrow2AlCl_3+3H_2\uparrow\)
a_____________________\(\dfrac{3}{2}\)a (mol)
\(Fe+2HCl\rightarrow FeCl_2+H_2\uparrow\)
b____________________b (mol)
Ta lập HPT: \(\left\{{}\begin{matrix}27a+56b=11\\\dfrac{3}{2}a+b=\dfrac{8,96}{22,4}=0,4\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}a=0,2\\b=0,1\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{Al}=\dfrac{0,2\cdot27}{11}\cdot100\%\approx49,09\%\\\%m_{Fe}=50,91\%\end{matrix}\right.\)
b) PTHH: \(CuO+H_2\xrightarrow[]{t^o}Cu+H_2O\)
Ta có: \(\left\{{}\begin{matrix}n_{CuO}=\dfrac{16}{80}=0,2\left(mol\right)\\n_{H_2}=\dfrac{3}{2}a+b=0,4\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\) H2 còn dư, tính theo CuO
\(\Rightarrow n_{Cu}=0,2\left(mol\right)\) \(\Rightarrow m_{Cu}=0,2\cdot64=12,8\left(g\right)\)
Gọi n Al = a ( mol ) , n Fe = b ( mol )
Có: n H2 = 0,4 ( mol )
PTHH
2AL + 6HCL ===> 2ALCL3 + 3H2
a--------------------------------------a
Fe + 2HCl ====> FeCL2 + H2
b------------------------------------b
Ta có hpt:
\(\left\{{}\begin{matrix}27a+56b=11\\1,5a+b=0,4\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}a=0,2\\b=0,1\end{matrix}\right.\)
=> m AL = 5,4 ( g ) ; m Fe = 5,6 ( g )
b) Có : n CuO = 0,2 ( mol )
PTHH:
CuO + H2 ====> Cu +H2O
0,2----0,2-----------0,2
theo pthh: n Cu = 0,2 ( mol ) => m Cu = 12,8 ( g )
\(n_{SO_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\)
PTHH: SO2 + Ca(OH)2 → CaSO3 + H2O
Mol: 0,1 0,1 0,1
\(V_{ddCa\left(OH\right)_2}=\dfrac{0,1}{1}=0,1\left(l\right)\)
\(m_{CaSO_3}=0,1.120=12\left(g\right)\)
a)
$Fe + H_2SO_4 \to FeSO_4 + H_2$
$n_{H_2} = n_{Fe} = \dfrac{2,8}{56} = 0,05(mol)$
$V_{H_2} = 0,05.22,4 = 1,12(lít)$
b)
$CuO + H_2 \xrightarrow{t^o} Cu + H_2O$
$n_{CuO} = n_{Cu} = n_{H_2} = 0,05(mol)$
$m_{CuO} = 0,05.80 = 4(gam)$
$m_{Cu} = 0,05.64 = 3,2(gam)$
\(n_{Fe}=\dfrac{2.8}{56}=0.05\left(mol\right)\)
\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)
\(0.05..............................0.05\)
\(V_{H_2}=0.05\cdot22.4=1.12\left(l\right)\)
\(CuO+H_2\underrightarrow{^{^{t^0}}}Cu+H_2O\)
\(n_{CuO}=n_{Cu}=n_{H_2}=0.05\left(mol\right)\)
\(m_{CuO}=0.05\cdot80=4\left(g\right)\)
\(m_{Cu}=0.05\cdot64=3.2\left(g\right)\)