PT: \(CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)

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

a, Giả sử: \(\left\{{}\begin{matrix}n_{CH_4}=x\left(mol\right)\\n_{C_2H_2}=y\left(mol\right)\end{matrix}\right.\)

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

Ta có: \(n_{CO_2}=\dfrac{35,84}{22,4}=1,6\left(mol\right)\)

Theo PT: \(\Sigma n_{CO_2}=n_{CH_4}+2n_{C_2H_2}\)

\(\Rightarrow x+2y=1,6\left(2\right)\)

Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}x=0,4\left(mol\right)\\y=0,6\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}\%V_{CH_4}=\dfrac{0,4}{1}.100\%=40\%\\\text{ }\%V_{C_2H_2}=60\%\end{matrix}\right.\)

b, Theo PT: \(\Sigma n_{O_2}=2n_{CH_4}+\dfrac{5}{2}n_{C_2H_2}=2,3\left(mol\right)\)

\(\Rightarrow m_{O_2}=2,3.32=73,6\left(g\right)\)

c, PT: \(CO_2+2NaOH\rightarrow Na_2CO_3+H_2O\)

Theo PT: \(n_{Na_2CO_3}=n_{CO_2}=1,6\left(mol\right)\)

\(\Rightarrow C_{M_{Na_2CO_3}}=\dfrac{1,6}{0,8}=2M\)

Bạn tham khảo nhé!

Gọi n CH4 = a(mol) ; n C2H4 = b(mol) ; n C2H2 = c(mol)

=> 16a + 28b + 26c = 10,4(1)

Bảo toàn nguyên tố với C :

n CO2 = a + 2b + 2c = 33/44 = 0,75(2)

$C_2H_4 + Br_2 \to C_2H_4Br_2$
$C_2H_2 + 2Br_2 \to C_2H_2Br_4$

n Br2 = n C2H4 + 2n C2H2 = b + 2c = 80/160 = 0,5(3)

Từ (1)(2)(3) suy ra a = 0,15 ; b = 0,1 ; c = 0,2

%m CH4 = 0,15.16/10,4  .100% = 23,08%
%m C2H4 = 0,1.28/10,4  .100% = 26,92%
%m C2H2 = 100%- 23,08% -26,92% = 50%

a) PTTH: \(2H_2+O_2\rightarrow2H_2O\)

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

b) Ta có: \(\left\{{}\begin{matrix}\overline{M}_{hhkhí}=0,5\cdot28=14\\n_{hhkhí}=\dfrac{13,44}{22,4}=0,6\left(mol\right)\end{matrix}\right.\)

Theo phương pháp đường chéo, ta có: \(\dfrac{n_{H_2}}{n_{C_2H_2}}=\dfrac{12}{12}=1\)

\(\Rightarrow n_{H_2}=n_{C_2H_2}=0,3\left(mol\right)\)

\(\Rightarrow\left\{{}\begin{matrix}\%V_{H_2}=\dfrac{0,3}{0,6}\cdot100\%=50\%\\\%V_{C_2H_2}=50\%\\\%m_{H_2}=\dfrac{0,3\cdot2}{5,6}\cdot100\%\approx10,71\%\\\%m_{C_2H_4}=89,29\%\end{matrix}\right.\)

\(M_X=2,5.16=40\)(g/mol)

\(\rightarrow\dfrac{V_{CO_2}}{V_{O_2}}=\dfrac{n_{CO_2}}{n_{O_2}}=\dfrac{40-32}{44-40}=2\)

Mà \(V_{CO_2}+V_{O_2}=30\left(L\right)\)

\(\rightarrow V_{CO_2}=20\left(L\right);V_{O_2}=10\left(L\right)\)

\(\rightarrow M_Y=\dfrac{20.44+10.32+32V}{V+20+10}=2,25.16=36\)

\(\rightarrow V=30\left(L\right)\)

Bài 1:

Ta có: \(n_{C_2H_2}=\dfrac{5,6}{22,4}=0,25\left(mol\right)\)

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

a, \(n_{O_2}=\dfrac{5}{2}n_{C_2H_2}=0,625\left(mol\right)\Rightarrow m_{O_2}=0,625.32=20\left(g\right)\)

b, \(n_{CO_2}=2n_{C_2H_2}=0,5\left(mol\right)\Rightarrow m_{CO_2}=0,5.44=22\left(g\right)\)

Bài 2:

Ta có: \(\%V_{C_2H_2}=\%V_{CH_4}=50\%\) (do tỉ lệ số mol 2 khí bằng nhau)

Chọn đáp án C.

X gồm: OHC-CHO, C₂H₂, CH₂(CHO)₂, HCOOCH=CH₂.
CTPT các chất là: C₂H₂O₂, C₂H₂, C₃H₄O₃.
n C 2 H 2 O 2 = n C 2 H 2
Áp dụng định luật bảo toàn nguyên tố O có:   x + 2 y + 2 n O 2 = x + 2 y + 2. 52 , 8 44
⇒ n O 2 = 1 , 2 m o l

0,12 mol (C₂H₆, C₃H₈) + 0,546 mol O₂ → a g CO₂

Có n H 2 O − n C O 2 = n a n k a n = 0 , 12 m o l      (1)

Áp dụng định luật bảo toàn nguyên tố O:  n H 2 O = 2.0 , 546 − 2 n C O 2     (2)

Từ (1), (2) suy ra  n C O 2 = 0 , 324 m o l ⇒ a = 44.0 , 324 = 14 , 256 g n H 2 O = 0 , 444 m o l

$\%m_{O_2(X)}=\dfrac{1,6}{1,6+4,4}.100\%=26,67\%$

$n_{CO_2}=\dfrac{4,4}{44}=0,1(mol);n_{O_2}=\dfrac{1,6}{16}=0,05(mol)$

$\Rightarrow \%V_{O_2(X)}=\dfrac{0,05}{0,05+0,1}.100\%=33,33\%$

$C+O_2\xrightarrow{t^o}CO_2$

Theo PT: $n_C=n_{O_2(p/ứ)}=n_{CO_2}=0,1(mol)$

$\Rightarrow n_{O_2(dùng)}=0,1+0,05=0,15(mol)$

$m_C=0,1.12=1,2(g);V_{O_2(dùng)}=0,15.22,4=3,36(lít)$

$\to m=1,2;V=3,36$

a, \(CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)

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

Ta có: \(n_{CH_4}+n_{C_2H_2}=\dfrac{6,72}{22,4}=0,3\left(mol\right)\left(1\right)\)

\(n_{CO_2}=n_{CH_4}+2n_{C_2H_2}=\dfrac{7,84}{22,4}=0,35\left(mol\right)\left(2\right)\)

Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}n_{CH_4}=0,25\left(mol\right)\\n_{C_2H_2}=0,05\left(mol\right)\end{matrix}\right.\)

\(\Rightarrow\left\{{}\begin{matrix}\%V_{CH_4}=\dfrac{0,25.22,4}{6,72}.100\%\approx83,33\%\\\%V_{C_2H_2}\approx16,67\%\end{matrix}\right.\)

Theo PT: \(n_{O_2}=2n_{CH_4}+\dfrac{5}{2}n_{C_2H_2}=0,625\left(mol\right)\Rightarrow m_{O_2}=0,625.32=20\left(g\right)\)