a) Ta có: \(\overline{M}=12\cdot2=24\)

Theo phương pháp đường chéo: \(n_{CH_4}=n_{O_2}\) \(\Rightarrow\%V_{CH_4}=\%V_{O_2}=50\%\)

Giả sử \(n_{O_2}=n_{CH_4}=1\left(mol\right)\) \(\Rightarrow\left\{{}\begin{matrix}\%m_{O_2}=\dfrac{32}{32+16}\cdot100\%\approx66,67\%\\\%m_{CH_4}=33,33\%\end{matrix}\right.\)

b) Ta có: \(n_{O_2}=n_{CH_4}=\dfrac{\dfrac{16,8}{22,4}}{2}=0,375\left(mol\right)\)

PTHH: \(CH_4+3O_2\xrightarrow[]{t^o}CO_2+2H_2O\)

Theo PTHH: \(n_{CO_2}=n_{CH_4}=0,375\left(mol\right)\)

\(\Rightarrow d_{hh/CH_4}=\dfrac{44\cdot0,375+32\cdot0,375}{16}=1,78125\)

Gọi số mol CH₄, O₂ là a, b (mol)

=> \(\left\{{}\begin{matrix}a+b=\dfrac{2,24}{22,4}=0,1\left(mol\right)\\\overline{M}=\dfrac{16a+32b}{a+b}=0,4375.64=28\end{matrix}\right.\)

=> \(\left\{{}\begin{matrix}a=0,025\\b=0,075\end{matrix}\right.\)

PTHH: CH₄ + 2O₂ --t^o--> CO₂ + 2H₂O

Xét tỉ lệ: \(\dfrac{0,025}{1}< \dfrac{0,075}{2}\) => CH₄ hết, O₂ dư

PTHH: CH₄ + 2O₂ --t^o--> CO₂ + 2H₂O

          0,025->0,05----->0,025

=> \(\left\{{}\begin{matrix}n_{CO_2}=0,025\left(mol\right)\\n_{O_2\left(dư\right)}=0,075-0,05=0,025\left(mol\right)\end{matrix}\right.\)

=> \(\%V_{CO_2}=\%V_{O_2\left(dư\right)}=\dfrac{0,025}{0,025+0,025}.100\%=50\%\)

`a)\ CH_4+2O_2`  $\xrightarrow{t^o}$  `CO_2+2H_2O`

`b)`

`M_X=14,4.2=28,8(g//mol)`

`->{n_{CH_4}}/{n_{O_2}}={32-28,8}/{28,8-16}=1/4`

Cho `n_{CH_4}=1(mol)->n_{O_2}=4(mol)`

`CH_4+2O_2`  $\xrightarrow{t^o}$  `CO_2+2H_2O`

`1->2->1->2(mol)`

Do `1<4/2->O_2` dư `4-2=2(mol)`

`->Y` gồm `CO_2:1(mol);O_2:2(mol)`

`->M_Y={1.44+2.32}/{1+2}=36(g//mol)`

`->d_{X //Y}={28,8}/{36}=0,8`

help me

1, a, + 8.2=16 => CH₄

+ 8,5 . 2 = 17 => NH₃

+ 16 . 2 =32 => O₂
+ 22 . 2 = 44 => CO₂

b, + 0,138 . 29 \(\approx4\) => He

+ 1,172 . 29 \(\approx34\) => H₂S

+ 2,448 . 29 \(\approx71\Rightarrow Cl_2\)

+ 0,965 . 29 \(\approx28\) => N

Giả sử các khí được đo ở điều kiện sao cho 1 mol khí chiếm thể tích 1 lít

Gọi số mol CH₄, C₂H₆ là a, b (mol)

=> \(a+b=\dfrac{25}{1}=25\left(mol\right)\) (1)

\(n_{O_2}=\dfrac{95}{1}=95\left(mol\right)\)

PTHH: CH₄ + 2O₂ --t^o--> CO₂ + 2H₂O

             a---->2a---------->a

            2C₂H₆ + 7O₂ --t^o--> 4CO₂ + 6H₂O

              b------>3,5b-------->2b

=> \(\left\{{}\begin{matrix}n_{O_2\left(dư\right)}=95-2a-3,5b\left(mol\right)\\n_{CO_2}=a+2b\left(mol\right)\end{matrix}\right.\)

=> \(95-a-1,5b=\dfrac{60}{1}=60\)

=> a + 1,5b = 35 (2)

(1)(2) => a = 5; b = 20

=> \(\left\{{}\begin{matrix}\%V_{CH_4}=\dfrac{5}{25}.100\%=20\%\\\%V_{C_2H_6}=\dfrac{20}{25}.100\%=80\%\end{matrix}\right.\)

\(\overline{M}_A=\dfrac{5.16+20.30}{5+20}=27,2\left(g/mol\right)\)

\(\overline{M}_B=20,5.2=41\left(g/mol\right)\)

=> \(d_{A/B}=\dfrac{27,2}{41}\approx0,663\)

Đáp án D

n_D = 0,45 => n_O(D) = 0,9 mol

n_Y = 0,05 mol

Đặt n_N2 = x => n_H2 = 0,05 – x

=> 28x + 2(0,05 – x) = 0,05.11,4.2 = 1,14

=> x = 0,04 mol

=> n_N2 = 0,04 mol và n_H2 = 0,01 mol

Trong Y chứa khí H₂ chứng tỏ NO₃^- hết

Hỗn hợp muối clorua gồm : a mol MgCl₂ ; 0,25 mol CuCl₂ ; NH₄Cl

Bảo toàn Clo : n_NH4Cl = 1,3 – 2a – 0,5 = 0,8 – 2a

Bảo toàn H : n_H2 = ½ (n_HCl + 4n_NH4Cl – 2n_H2) = 4a – 0,96

Bảo toàn O : n_O (Cu(NO₃)₂) = n_O(D) + n_O(H2O) => 0,25.6 = 0,9 + 4a – 0,96

=> a = 0,39 mol

=> m = 0,39.95 + 0,25.135 + (0,8 – 2.0,39). 53,5 = 71,87g

Đặt \(n_{O_2}=x;n_{CO_2}=y\)

\(n_X=\dfrac{4,48}{22,4}=0,2\left(mol\right)\Leftrightarrow x+y=0,2\) 

Ta có: \(16x+44y=\left(x+y\right).18.2\)

     \(\Leftrightarrow2y=5x\)

     \(\Leftrightarrow\dfrac{y}{5}=\dfrac{x}{2}\)

Mà x+y=0,2

\(\Rightarrow\dfrac{y}{5}=\dfrac{x}{2}=\dfrac{x+y}{5+2}=\dfrac{0,2}{7}=0,0286\)

\(\Rightarrow y=5.0,0286=0,143\left(mol\right);x=0,2-0,143=0,057\left(mol\right)\)