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\(nC_2H_5OH=\dfrac{2,9}{46}=0,06\left(mol\right)\)
\(C_2H_5OH+Na\rightarrow C_2H_5ONa+\dfrac{1}{2}H_2\)
0,06 0,06 0,06 0,03 (mol)
VH2 = 0,03.22,4= 0,672 (l)
V = m /D
=> V rượu etylic = 2,9 / 0,8 = 3,625 (ml)
\(a,V_{C_2H_5OH}=\dfrac{96.30}{100}=28,8\left(ml\right)\\ \rightarrow m_{C_2H_5OH}=28,8.0,8=23,04\left(ml\right)\\ \rightarrow n_{C_2H_5OH}=\dfrac{23,04}{46}=0,5\left(mol\right)\)
PTHH: 2C2H5OH + 2Na ---> 2C2H5ONa + H2
0,5----------------------------------->0,25
\(\rightarrow V_{H_2}=0,25.22,4=5,6\left(l\right)\)
b, \(n_{CH_3COOH}=\dfrac{36}{60}=0,6\left(mol\right)\)
PTHH: \(C_2H_5OH+CH_3COOH\xrightarrow[t^o]{H_2SO_{4\left(đ\right)}}CH_3COOC_2H_5+H_2O\)
LTL: 0,5 < 0,6 => CH3COOH dư
Theo pthh: nCH3COOH = nC2H5OH = 0,5 (mol)
=> meste = 0,5.88.70% = 30,8 (g)
Đáp án: A
Vì dung dịch rượu gồm rượu etylic và nước nên ta gọi:
n H 2 O = x m o l và n C 2 H 5 O H = y m o l
PTHH:
2 N a + 2 H 2 O → 2 N a O H + H 2 ↑ ( 1 )
x mol → 0,5.x mol
2 N a + 2 C 2 H 5 O H → 2 C 2 H 5 O N a + H 2 ↑
y mol → 0,5.y mol
Ta có hệ phương trình:
18 x + 46 y = 10 , 1 0 , 5 x + 0 , 5 y = 0 , 125 ⇒ x = 0 , 05 y = 0 , 2
V C 2 H 5 O H nguyên chất = m D = 0 , 2 . 46 0 , 8 = 11 , 5 m l
V H 2 O = m D = 10 , 1 - 9 , 2 1 = 0 , 9 m l
=> V d d r ư ợ u = V H 2 O + V C 2 H 5 O H = 0,9 + 11,5 = 12,4 ml
=> Độ rượu D 0 = V C 2 H 5 O H V d d r u o u . 100 = 11 , 5 12 , 4 . 100 = 92 , 74 0
\(V_{C_2H_5OH}=\dfrac{100.40}{100}=40\left(ml\right)\\ \rightarrow m_{C_2H_5OH}=40.0,8=32\left(g\right)\\ \rightarrow n_{C_2H_5OH}=\dfrac{32}{46}=\dfrac{16}{23}\left(mol\right)\)
PTHH: \(C_2H_5OH+Na\rightarrow C_2H_5ONa+\dfrac{1}{2}H_2\uparrow\)
\(\dfrac{16}{23}\)----------------------------------->\(\dfrac{8}{23}\)
\(\rightarrow V_{H_2}=\dfrac{8}{23}.22,4=\dfrac{896}{115}\left(l\right)\)
Gọi \(\left\{{}\begin{matrix}n_{C_2H_5OH}=a\left(mol\right)\\n_{H_2O}=b\left(mol\right)\end{matrix}\right.\)
\(n_{H_2}=\dfrac{5,6}{22,4}=0,25\left(mol\right)\)
PTHH:
2C2H5OH + 2Na ---> 2C2H5ONa + H2
a --------------------------------------------> 0,5a
2H2O + 2Na ---> 2NaOH + H2
b --------------------------------> 0,5b
Hệ pt \(\left\{{}\begin{matrix}46a+18b=20,2\\0,5a+0,5b=0,25\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,4\left(mol\right)\\b=0,1\left(mol\right)\end{matrix}\right.\)
\(\rightarrow\left\{{}\begin{matrix}m_{C_2H_5OH}=0,4.46=18,4\left(g\right)\\m_{H_2O}=0,1.18=1,8\left(g\right)\end{matrix}\right.\rightarrow\left\{{}\begin{matrix}V_{C_2H_5OH}=\dfrac{18,4}{0,8}=23\left(ml\right)\\V_{H_2O}=\dfrac{1,8}{1}=1,8\left(ml\right)\end{matrix}\right.\)
=> Độ rượu là: \(\dfrac{23}{23+1,8}=92,74^o\)
\(n_{C_2H_4}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\)
PTHH: C2H4 + H2O \(\xrightarrow[Axit]{Men.rượu}\) C2H5OH
0,2 0,2
\(m_{C_2H_5OH}=0,2.46.80\%=7,36\left(g\right)\\ V_{C_2H_5OH}=\dfrac{7,36}{0,8}=9,2\left(ml\right)\)
\(n_{C_2H_4}=\dfrac{4,48}{22,4}=0,2mol\)
\(C_2H_4+H_2O\xrightarrow[axit]{lên.men}C_2H_5OH\)
0,2 0,2 ( mol )
\(m_{C_2H_5OH}=0,2.46.80\%=7,36g\)
\(C_{C_2H_5OH}=\dfrac{7,36}{0,8}=9,2ml\)
nH2 = 85,12 : 22,4 = 3,8 (mol) ; nH2O = VH2O.D = 108 (g) => nH2O = 108/18 = 6 (mol)
PTHH:
2Na + 2C2H5OH → 2C2H5ONa + H2↑
x → 0,5x (mol)
2Na + 2H2O → 2NaOH + H2↑
6 → 3 (mol)
Ta có: nH2 = 0,5x + 3 = 3,8
=> x = 1,6 (mol) = nC2H5OH
mC2H5OH = 1,6.46 = 73,6 (g)
a)
\(V_{C_2H_5OH}=\dfrac{96.20}{100}=19,2\left(ml\right)\)
=> \(m_{C_2H_5OH}=19,2.0,8=15,36\left(g\right)\)
b) \(n_{C_2H_5OH}=\dfrac{15,36}{46}=\dfrac{192}{575}\left(mol\right)\)
\(V_{H_2O}=20-19,2=0,8\left(ml\right)\)
=> \(m_{H_2O}=0,8.1=0,8\left(g\right)\)
=> \(n_{H_2O}=\dfrac{0,8}{18}=\dfrac{2}{45}\left(mol\right)\)
PTHH: 2C2H5OH + 2Na --> 2C2H5ONa + H2
\(\dfrac{192}{575}\)------------------------->\(\dfrac{96}{575}\)
2H2O + 2Na --> 2NaOH + H2
\(\dfrac{2}{45}\)----------------------->\(\dfrac{1}{45}\)
=> \(V_{H_2}=22,4.\left(\dfrac{96}{575}+\dfrac{1}{45}\right)=4,238\left(l\right)\)
C2H5OH + Na -- > C2H5OHNa + 1/2 H2
Na+H2O --- > NaOH + 1/2H2
Vr = 20x96/100 = 19,2ml = 0.0192 (l)
mC2H5OH = D.V = 19,2 x 0.8 = 15.36 (g)
nC2H5OH = m/M = 15.36 / 46 = 0.43 (mol)
=> nH2 = 0.215 (mol)
VH2O = 1 ml => mH2O = 1 (g)
=> nH2O = m/M = 1/18 = 0.056 (mol)
=> nH2 = 0.028 (mol)
nH2 = 0.215 + 0.028 = 0.243 (mol)
=> VH2 = 22.4 x 0,243 = 5,4432 (l)