Ai giúp e với ạ

Đáp án: B

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

b) Ta có: \(n_{Br_2}=\dfrac{11,2}{160}=0,07\left(mol\right)=n_{C_2H_4}\)

\(\Rightarrow\%V_{C_2H_4}=\dfrac{0,07\cdot22,4}{1,72}\cdot100\%\approx91,16\%\) 

\(\Rightarrow\%V_{CH_4}=8,84\%\)

a) \(C_2H_4 + Br_2 \to C_2H_4Br_2\)

b)

\(n_{C_2H_4} = n_{Br_2} = \dfrac{5,6}{160} = 0,035(mol)\\ \%V_{C_2H_4} = \dfrac{0,035.22,4}{0,86}.100\% = 91,16\%\\ \%V_{CH_4} = 100\% - 91,16\% = 8,84\%\)

a, PT: \(C_2H_4+Br_2\rightarrow C_2H_4Br_2\)

\(C_2H_2+2Br_2\rightarrow C_2H_2Br_4\)

Giả sử: \(\left\{{}\begin{matrix}n_{C_2H_4}=x\left(mol\right)\\n_{C_2H_2}=y\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow x+y=\dfrac{1,344}{22,4}=0,06\left(1\right)\)

Ta có: \(n_{Br_2}=\dfrac{16}{160}=0,1\left(mol\right)\)

Theo PT: \(n_{Br_2}=n_{C_2H_4}+2n_{C_2H_2}=x+2y\left(mol\right)\)

⇒ x + 2y = 0,1 (2)

Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}x=0,02\left(mol\right)\\y=0,04\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}\%V_{C_2H_4}=\dfrac{0,02}{0,06}.100\%\approx33,33\%\\\%\text{ }V_{C_2H_2}\approx66,67\%\end{matrix}\right.\)

b, Ta có: 1/2 hỗn hợp khí gồm: 0,01 mol C₂H₄ và 0,02 mol C₂H₂.

PT: \(C_2H_4+3O_2\underrightarrow{t^o}2CO_2+2H_2O\)

\(2C_2H_2+5O_2\underrightarrow{t^o}4CO_2+2H_2O\)

Theo PT: \(n_{CO_2}=2n_{C_2H_4}+2n_{C_2H_2}=0,06\left(mol\right)\)

\(CO_2+Ca\left(OH\right)_2\rightarrow CaCO_{3\downarrow}+H_2O\)

Theo PT: \(n_{CaCO_3}=n_{CO_2}=0,06\left(mol\right)\)

\(\Rightarrow m_{cr}=m_{CaCO_3}=0,06.100=6\left(g\right)\)

Bạn tham khảo nhé!

Theo gt ta có: $n_{hh}=0,08(mol);n_{Br_2}=0,08(mol)$

$C_2H_2+2Br_2\rightarrow C_2H_2Br_4$

Suy ra $n_{C_2H_2}=0,04(mol)=n_{CH_4}$

a, $\Rightarrow \%V_{C_2H_2}=\%V_{C_2H_4}=50\%$

b, $CH_4+2O_2\rightarrow CO_2+2H_2O$

$2C_2H_2+5O_2\rightarrow 4CO_2+2H_2O$

Ta có: $n_{O_2}=0,04.2+0,04.5=0,28(mol)\Rightarrow m_{O_2}=8,96(g)$

\(a)C_2H_2 +2Br_2 \to C_2H_2Br_2\\ n_{C_2H_2} = \dfrac{1}{2}n_{Br_2} = \dfrac{0,4.0,2}{2} = 0,04(mol)\\ \Rightarrow V_{C_2H_2} = 0,04.22,4 = 0,896(lít)\\ \%V_{C_2H_2} =\dfrac{0,896}{1,792}.100\% = 50\%\\ \Rightarrow \%V_{CH_4} = 100\% -50\% = 50\%\\ b)\\V_{CH_4} = V_{C_2H_2} = 0,896(lít)\\ CH_4 + 2O_2 \xrightarrow{t^o} CO_2 + 2H_2O\\ C_2H_2 + \dfrac{5}{2}O_2 \xrightarrow{t^o} 2CO_2 + H_2O\\ \)

\(V_{O_2} = 2V_{CH_4} + \dfrac{5}{2}V_{C_2H_2} = 4,032(lít)\\ \Rightarrow m_{O_2} = \dfrac{4,032}{22,4}.32 = 5,76(gam)\)

Đáp án A

Đặt n_CH4 = x mol, n_C2H2 = y mol → x + y =0,25 mol

n_Br2(pư) = 2y =0,1 mol → y =0,05 mol

→ x = 0,2 mol

→ V_CH4 = 4,48 lít và V_C2H2 =1,12 lít

\(n_{anken} = n_{Br_2} =\dfrac{80}{160} = 0,5(mol)\\ \Rightarrow V_{anken} = 0,5.22,4 = 11,2(lít)\\ \Rightarrow V_{metan} = 4,48 - 11,2 =-6,72 <0\)

(Sai đề)

\(n_{Br_2}=\dfrac{5,6}{160}=0,035\left(mol\right)\)

PTHH: C₂H₂ + 2Br₂ --> C₂H₂Br₄

         0,0175<-0,035

=> \(\%V_{C_2H_2}=\dfrac{0,0175.22,4}{0,56}.100\%=70\%\)

=> %V_CH4 = 100% - 70% = 30% 

=> B

C2H2+2Br2->C2H2Br2

0,0175---0,035

n Br2=\(\dfrac{5,6}{160}\)=0,035 mol

=>%VC2H2=\(\dfrac{0,0175.22,4}{0,56}.100\)=70%

=>%VCH4=100-70=30%

B

a) nC2H4Br2=47/188=0,25(mol)

n(CH4,C2H4)=11,2/22,4=0,5(mol)

PTHH: C2H4 + Br2 -> C2H4Br2

0,25<----------0,25<---------0,25(mol)

mBr2(p.ứ)=0,25 x 160= 40(g)

b) V(C2H4,đktc)=0,25 x 22,4= 5,6(l)

=> %V(C2H4)=(5,6/11,2).100=50%

=>%V(CH4)=100% - 50%= 50%