- Do dung dịch brom dư, nên khí thoát ra là metan.

- Chọn đáp án A.

a) \(n_{C_2H_4Br_2}=\dfrac{4,7}{188}=0,025\left(mol\right)\)

PTHH: \(C_2H_4+Br_2\rightarrow C_2H_4Br_2\)

           0,025<------------0,025

b) \(\left\{{}\begin{matrix}V_{C_2H_4}=0,025.22,4=0,56\left(l\right)\\V_{CH_4}=5,6-0,56=5,04\left(l\right)\end{matrix}\right.\)

a) \(n_{C_2H_4Br_2}=\dfrac{18,8}{188}=0,1\left(mol\right)\)

PTHH: C₂H₄ + Br₂ --> C₂H₄Br₂

            0,1<----0,1<---0,1

=> \(m_{Br_2}=0,1.160=16\left(g\right)\)

b)

\(\%V_{C_2H_4}=\dfrac{0,1.22,4}{4}.100\%=56\%\)

=> \(\%V_{CH_4}=100\%-56\%=44\%\)

c) \(n_{CH_4}=\dfrac{4.44\%}{22,4}=\dfrac{11}{140}\left(mol\right)\)

PTHH: CH₄ + 2O₂ --t^o--> CO₂ + 2H₂O

          \(\dfrac{11}{140}\)-->\(\dfrac{11}{70}\)

            C₂H₄ + 3O₂ --t^o--> 2CO₂ + 2H₂O

           0,1---->0,3

=> \(V_{O_2}=\left(\dfrac{11}{70}+0,3\right).22,4=10,24\left(l\right)\)

=> V_kk = 10,24.5 = 51,2 (l)

\(n_{C_2H_4Br_2}=\dfrac{1,7}{188}=\dfrac{17}{1880}\left(mol\right)\\C_2H_4+Br_2\rightarrow C_2H_4Br_2 \\ \Rightarrow n_{C_2H_4}=n_{C_2H_4Br_2}=n_{Br_2}=\dfrac{17}{1880}\left(mol\right)\\ a,m_{Br_2}=\dfrac{17}{1880}.160=\dfrac{68}{47}\left(g\right)\\ b,\%V_{C_2H_4}=\dfrac{\dfrac{17}{1880}.22,4}{3}.100\approx6,752\%\Rightarrow\%V_{CH_4}\approx93,248\%\)

a)C₂H₄ + Br₂ -> C₂H₄Br₂

nC₂H₄Br₂ = 1,7/ 188= 0,009(mol)

→ nBr₂ =0,009 (mol)

→ mBr₂= 1,44 g nhé

Cho hỗn hợp qua dung dịch brom chỉ có etylen tác dụng.

\(n_{Br_2}=0,25\cdot1,5=0,375mol\)

\(C_2H_4+Br_2\rightarrow C_2H_4Br_2\)

0,375     0,375

\(V_{C_2H_4}=0,375\cdot22,4=8,4l\Rightarrow V_{CH_4}=11-8,4=2,6l\)

nC2H4Br2= 0.1 (mol)

C2H4 + Br2 --> C2H4Br2

nC2H4= 0.1 (mol)

VC2H4= 2.24l

VCH4= 4-2.24=1.76l

%CH4= 44%

%C2H4= 56%

Đáp án A