cho hh A gồm rượu etylic và axit axetic . cho 21,1 g A pư vs K dư thu đc 4,48l khí . tính phần trăm khối lượng hh A
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\(n_{H_2}=\dfrac{0,672}{22,4}=0,03\left(mol\right)\)
PTHH:
\(CH_3COOH+NaOH\rightarrow CH_3COONa+H_2O\)
0,04<------------0,04
\(CH_3COOH+Na\rightarrow CH_3COONa+\dfrac{1}{2}H_2\uparrow\)
0,04----------------------------------------->0,02
\(C_2H_5OH+Na\rightarrow C_2H_5ONa+\dfrac{1}{2}H_2\uparrow\)
0,005<--------------------------------0,01
\(\rightarrow m_{C_2H_5OH}=0,005.46=0,23\left(g\right)\)
2C2H5OH + 2Na--> 2C2H5Na + H2
a a/2 mol
2CH3COOH + 2Na --> 2CH3COONa + H2
b b/2 mol
n khí = 3,36/22,4=0,15 mol
=> a/2 + b/2 =0,15
và 46a + 60 b =15,2
=> a=0,2 mol : b=0,1 mol
=> mC2H5OH = 0,2 * 46=9,2 g
=>% mC2H5OH = 9,2*100/15,2=60,53%
% mCH3COOH = 100 - 60 ,53=39,47 %
n H2 =0,3 mol
n NaOH =0,2 mol
=>n OH= n H+ =0,2 mol
=>n CH3COOH=0,2 mol
=>m CH3COOH=0,2.60=12g
->n C2H5OH=0,1 mol
=>m C2H5OH=4,6g
=>mC2H5OH=\(\dfrac{4,6}{4,6+12}100=27,71\%\)
=>maxit=72,29%
b)
CH3COOH+C2H5OH->CH3COOC2H5+H2O
0,1-------------0,1
=>H=82%
=>m CH3COOC2H5=0,082.88=7,216g
a, \(n_{C_2H_4}=\dfrac{15,68}{22,4}=0,7\left(mol\right)\)
PT: \(C_2H_4+H_2O\underrightarrow{^{t^o,xt}}C_2H_5OH\)
Theo PT: \(n_{C_2H_5OH\left(LT\right)}=n_{C_2H_4}=0,7\left(mol\right)\)
Mà: H = 90%
\(\Rightarrow n_{C_2H_5OH\left(TT\right)}=0,7.90\%=0,63\left(mol\right)\)
\(\Rightarrow m_{C_2H_5OH\left(TT\right)}=0,63.46=28,98\left(g\right)\)
\(\Rightarrow V_{C_2H_5OH}=\dfrac{28,98}{0,8}=36,225\left(ml\right)\)
b, \(C_2H_5OH+O_2\underrightarrow{^{mengiam}}CH_3COOH+H_2O\)
Theo PT: \(n_{CH_3COOH}=n_{C_2H_5OH}=0,63\left(mol\right)\)
\(\Rightarrow m_{CH_3COOH}=0,63.60=37,8\left(g\right)\)
\(\Rightarrow m_{ddCH_3COOH}=\dfrac{37,8}{5\%}=756\left(g\right)\)
- Đặt \(\left\{{}\begin{matrix}n_{Al}=a\left(mol\right)\\n_{Mg}=b\left(mol\right)\end{matrix}\right.\Rightarrow27a+24b=10,2\left(1\right)\)
Khí thu được sau p/ứ là khí H2: \(n_{H_2}=\dfrac{11,2}{22,4}=0,5\left(mol\right)\)
\(2Al+6HCl\rightarrow2AlCl_3+3H_2\uparrow\)
2 3 (mol)
a 3/2 a (mol)
\(Mg+2HCl\rightarrow MgCl_2+H_2\uparrow\)
1 1 (mol)
b b (mol)
Từ hai PTHH trên ta có: \(\dfrac{3}{2}a+b=0,5\left(2\right)\)
\(\left(1\right),\left(2\right)\) ta có hệ: \(\left\{{}\begin{matrix}27a+24b=10,2\\\dfrac{3}{2}a+b=0,5\end{matrix}\right.\)
Giải ra ta có \(\left\{{}\begin{matrix}a=0,2\left(mol\right)\\b=0,2\left(mol\right)\end{matrix}\right.\)
a) \(\%Al=\dfrac{m_{Al}}{m_{hh}}.100\%=\dfrac{0,2.27}{10,2}.100\%\approx52,94\%\)
\(\%Mg=100\%-\%Al=100\%-52,94=47,06\%\)
b)
\(3H_2+Fe_2O_3\rightarrow^{t^0}2Fe+3H_2O\)
3 1 2 (mol)
0,5 1/6 1/3 (mol)
\(m_{Fe}=\dfrac{1}{3}.56=\dfrac{56}{3}\left(g\right)\)
\(m_{Fe_2O_3\left(pứ\right)}=\dfrac{1}{6}.160=\dfrac{80}{3}\left(g\right)\)
\(m_{Fe_2O_3\left(dư\right)}=60-m_{Fe}=60-\dfrac{56}{3}=\dfrac{124}{3}\left(g\right)\)
\(a=\dfrac{124}{3}+\dfrac{80}{3}=68\left(g\right)\)
Gọi \(\left\{{}\begin{matrix}n_{C2H5OH}:x\left(mol\right)\\n_{CH3COOH}:y\left(mol\right)\end{matrix}\right.\)
Ta có:
\(n_{H2}=\frac{4,48}{22,4}=0,2\left(mol\right)\)
\(2C_2H_5OH+2K\rightarrow C_2H_5OK+H_2\)
\(2CH_3COOH+2K\rightarrow2CH_3COOK+H_2\)
Giải hệ PT:
\(\left\{{}\begin{matrix}4x+100y=21,1\\0,5x+0,5y=0,2\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=0,35\\y=0,05\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{C2H5OH}=\frac{0,35.46}{21,1}.100\%=76,3\%\\\%m_{CH3COOH}=100\%-76,3\%=23,7\%\end{matrix}\right.\)