Cho 3,72g hh nhôm, nhôm oxit tác dụng vừa đủ với 131,4g dd ax HCl (D=1,04g/ml), sau phản ứng thu 3,36l khí dktc.
Tính nồng độ phần trăm và nồng độ mol của dd HCl
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a) 2Al + 6HCl --> 2AlCl3 + 3H2
b) \(n_{Al}=\dfrac{2,7}{27}=0,1\left(mol\right)\); nHCl = 0,5.2 = 1 (mol)
Xét tỉ lệ: \(\dfrac{0,1}{2}< \dfrac{1}{6}\) => Al hết, HCl dư
PTHH: 2Al + 6HCl --> 2AlCl3 + 3H2
0,1->0,3---->0,1---->0,15
=> VH2 = 0,15.22,4 = 3,36 (l)
c) \(\left\{{}\begin{matrix}C_{M\left(AlCl_3\right)}=\dfrac{0,1}{0,5}=0,2M\\C_{M\left(HCl.dư\right)}=\dfrac{1-0,3}{0,5}=1,4M\end{matrix}\right.\)
Theo gt ta có: $n_{Al}=0,1(mol)$
a, $2Al+6HCl\rightarrow 2AlCl_3+3H_2$
b, $\Rightarrow n_{H_2}=0,15(mol)\Rightarrow V_{H_2}=3,36(l)$
c, Ta có: $n_{HCl}=0,3(mol)\Rightarrow m_{HCl}=10,95(g)\Rightarrow \%m_{ddHCl}=219(g)$
d, Bảo toàn khối lượng ta có: $m_{dd}=221,4(g)$
$\Rightarrow \%C_{AlCl_3}=6,02\%$
PTHH: \(CuO+2HCl\rightarrow CuCl_2+H_2O\)
Ta có: \(n_{CuO}=\dfrac{4}{80}=0,05\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{HCl}=0,1\left(mol\right)\\n_{CuCl_2}=0,05\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}m_{ddHCl}=\dfrac{0,1\cdot36,5}{7,3\%}=50\left(g\right)\\C\%_{CuCl_2}=\dfrac{0,05\cdot135}{4+50}\cdot100\%=12,5\%\end{matrix}\right.\)
a) \(n_{Na_2CO_3}=\dfrac{21,2}{106}=0,2\left(mol\right)\)
PTHH: Na2CO3 + 2HCl --> 2NaCl + CO2 + H2O
0,2------------------>0,4---->0,2
mdd sau pư = 200 + 21,2 - 0,2.44 = 212,4(g)
=> \(C\%\left(NaCl\right)=\dfrac{0,4.58,5}{212,4}.100\%=11,017\%\)
$PTHH:Na_2CO_3+2HCl\to 2NaCl+H_2O+CO_2\uparrow$
$n_{Na_2CO_3}=\dfrac{21,2}{106}=0,2(mol)$
Theo PT: $n_{NaCl}=n_{CO_2}=0,2(mol)$
$\Rightarrow m_{NaCl}=0,4.58,5=23,4(g);m_{CO_2}=0,2.44=8,8(g)$
$\Rightarrow C\%_{NaCl}=\dfrac{23,4}{21,2+200-8,8}.100\%\approx 11,01\%$
\(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)
a.
\(Fe+2HCl\rightarrow FeCl_2+H_2\)
\(V_{H_2}=24,79.0,2=4,958\left(l\right)\)
b.
\(n_{HCl}=2.n_{Fe}=0,4\left(mol\right)\\ CM_{HCl}=\dfrac{0,4}{0,2}=2M\)
Ta có: \(n_{H_2}=\dfrac{10,08}{22,4}=0,45\left(mol\right)\)
PT: \(2Al+6HCl\rightarrow2AlCl_3+3H_2\)
_____0,3_____0,9______0,2____0,45 (mol)
a, mAl = 0,3.27 = 8,1 (g)
b, \(C_{M_{HCl}}=\dfrac{0,9}{0,15}=6\left(M\right)\)
\(a,n_{H_2SO_4}=0,5\cdot0,1=0,05\left(mol\right)\\ PTHH:2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\\ \Rightarrow n_{H_2}=n_{H_2SO_4}=0,05\left(mol\right)\\ \Rightarrow V_{H_2\left(đktc\right)}=0,05\cdot22,4=1,12\left(l\right)\\ b,n_{Al}=\dfrac{2}{3}n_{H_2SO_4}=\dfrac{1}{30}\left(mol\right)\\ \Rightarrow m_{Al}=\dfrac{1}{30}\cdot27=0,9\left(g\right)\\ c,n_{Al_2\left(SO_4\right)_3}=\dfrac{1}{3}n_{H_2SO_4}\approx0,017\left(mol\right)\\ \Rightarrow C_{M_{Al_2\left(SO_4\right)_3}}=\dfrac{0,017}{0,1}\approx0,17M\)
a) \(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\)
PTHH: 2Al + 6HCl --> 2AlCl3 + 3H2
_____0,2-->0,6----->0,2---->0,3
=> \(C_{M\left(HCl\right)}=\dfrac{0,6}{0,2}=3M\)
b) VH2 = 0,3.24,79 = 7,437 (l)
c) \(C_{M\left(AlCl_3\right)}=\dfrac{0,2}{0,2}=1M\)
\(n_{H2}=\frac{3,36}{22,4}=0,15\left(mol\right)\)
\(PTHH:2Al+6HCl\rightarrow2AlCl_3+3H_2\)
0,1_____________________________0,15
\(Al_2O_3+6HCl\rightarrow2AlCl_3+3H_2O\)
\(m_{Al2O3}=3,72-0,1.27=1,02\left(g\right)\)
\(\rightarrow n_{AlCl3}=n_{Al}+2n_{Al2O3}=0,12\left(mol\right)\)
\(\rightarrow n_{Al2O3}=\frac{1,02}{102}=0,1\left(mol\right)\)
Khối lượng dd sau phản ứng
\(m=3,71+131,4-0,15.2=134,82\)
\(\rightarrow C\%_{AlCl3}=\frac{0,12.133,5}{134,82}=11,88\%\)
Vdd sau phản ứng \(\frac{131,1}{1,04}=126\left(ml\right)=0,126l\)
\(\rightarrow CM_{AlCl3}=\frac{0,12}{0,126}=0,95M\)
C% và CM của dd HCl ạ