4. Cho 3( g) h2 khí gồm CH4 và C2H4 ( etilen) cần vừa đủ ( metan) V lít O2 (đkc), thu H2O và CO2 4,48 lít ( đkc). a, Viết PTHH . b, giá trị V . c, tính % thể tích các khí ban đầu
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nO (trong CO2) = 2 . nCO2 = 2 . 26,4/44 = 1,2 (mol)
nO (trong H2O) = nH2O = 13,5/18 = 0,75 (mol)
nO (trong O2) = 1,2 + 0,75 = 1,95 (mol)
nO2 = 1,95/2 = 0,975 (mol)
VO2 = 0,975 . 22,4 = 21,84 (l)
Vkk = 21,84 . 5 = 109,2 (l)
nO (trong CO2) = 2 . nCO2 = 2 . 26,4/44 = 1,2 (mol)
nO (trong H2O) = nH2O = 13,5/18 = 0,75 (mol)
nO (trong O2) = 1,2 + 0,75 = 1,95 (mol)
nO2 = 1,95/2 = 0,975 (mol)
VO2 = 0,975 . 22,4 = 21,84 (l)
Vkk = 21,84 . 5 = 109,2 (l)
a, \(CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)
\(C_2H_4+3O_2\underrightarrow{t^o}2CO_2+2H_2O\)
\(2C_2H_2+5O_2\underrightarrow{t^o}4CO_2+2H_2O\)
b, Sửa đề: 17,9 (l) → 17,92 (l)
Ta có: \(n_{CO_2}=\dfrac{17,92}{22,4}=0,8\left(mol\right)=n_C\)
\(n_{H_2O}=\dfrac{18}{18}=1\left(mol\right)\Rightarrow n_H=1.2=2\left(mol\right)\)
⇒ mA = mC + mH = 0,8.12 + 2.1 = 11,6 (g)
Theo ĐLBT KL, có: mA + mO2 = mCO2 + mH2O
⇒ mO2 = 0,8.44 + 18 - 11,6 = 41,6 (g)
\(\Rightarrow n_{O_2}=\dfrac{41,6}{32}=1,3\left(mol\right)\Rightarrow V_{O_2}=1,3.22,4=29,12\left(l\right)\)
\(n_{CO_2}=\dfrac{9,916}{24,79}=0,4\left(mol\right);n_{CH_4}=\dfrac{7,437}{24,79}=0,3\left(mol\right)\\ a,CH_4+2O_2\rightarrow\left(t^o\right)CO_2+2H_2O\\ C_2H_4+3O_2\rightarrow\left(t^o\right)2CO_2+2H_2O\\ Đặt:n_{CH_4}=a\left(mol\right);n_{C_2H_4}=b\left(mol\right)\left(a,b>0\right)\\ \Rightarrow\left\{{}\begin{matrix}a+2b=0,4\\a+b=0,3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,2\\b=0,1\end{matrix}\right.\\ \Rightarrow\%V_{CH_4}=\%n_{CH_4}=\dfrac{a}{0,3}.100\%=\dfrac{0,2}{0,3}.100\approx66,667\%\\ \Rightarrow\%V_{C_2H_4}\approx33,333\%\\ c,C_2H_4+Br_2\rightarrow C_2H_4Br_2\\ n_{Br_2}=n_{C_2H_4}=0,1\left(mol\right)\\ \Rightarrow C_{MddBr_2}=\dfrac{0,1}{0,2}=0,5\left(M\right)\)
Chỗ kia chắc 200ml dung dịch Br2 chứ 200gam thì cần cho thêm KLR á em
a. \(CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)
a 2a a
\(C_2H_4+3O_2\underrightarrow{t^o}2CO_2+2H_2O\)
b 3b 2b
b. \(n_{O_2}=\dfrac{25.88}{22.4}=1.155mol\)
n hỗn hợp khí \(=\dfrac{11.2}{22.4}=0.5mol\)
Ta có: \(\left\{{}\begin{matrix}a+b=0.5\\2a+3b=1.155\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0.345\\b=0.155\end{matrix}\right.\)
\(\%V_{CH_4}=\dfrac{0.345\times22.4\times100}{11.2}=69\%\)
\(\%V_{C_2H_4}=100-69=31\%\)
c. \(V_{CO_2}=\left(a+2b\right)\times22.4=\left(0.345+2\times0.155\right)\times22.4=14.672l\)
\(2Na + 2H_2O \to 2NaOH + H_2\\ Ba + 2H_2O \to Ba(OH)_2 + H_2\\ n_{H_2} =\dfrac{2,24}{22,4} = 0,1(mol)\\ \Rightarrow n_{OH^-} = 2n_{H_2} = 0,2(mol)\\ CO_2 + OH^- \to HCO_3^-\\ n_{CO_2} = n_{OH^-} = 0,2(mol) \Rightarrow V = 0,2.22,4 = 4,48(lít) \)
1. \(n_{Br_2}=0,4.0,5=0,2\left(mol\right)\)
PT: \(C_2H_4+Br_2\rightarrow C_2H_4Br_2\)
Theo PT: \(n_{C_2H_4}=n_{Br_2}=0,2\left(mol\right)\Rightarrow V_{C_2H_4}=0,2.22,4=4,48\left(l\right)\)
2. \(n_{C_2H_4Br_2}=\dfrac{9,4}{188}=0,05\left(mol\right)\)
PT: \(C_2H_4+Br_2\rightarrow C_2H_4Br_2\)
Theo PT: \(n_{C_2H_4}=n_{C_2H_4Br_2}=0,05\left(mol\right)\)
\(\Rightarrow\%V_{C_2H_4}=\dfrac{0,05.22,4}{1,4}.100\%=80\%\)
\(\Rightarrow\%V_{CH_4}=100-80=20\%\)
\(Đặt:\left\{{}\begin{matrix}a=n_{CH_4}\\b=n_{C_2H_4}\end{matrix}\right.\left(a,b>0\right)\\ a.CH_4+2O_2\underrightarrow{^{to}}CO_2+2H_2O\\ C_2H_4+3O_2\underrightarrow{^{to}}2CO_2+2H_2O\\ \Rightarrow\left\{{}\begin{matrix}16a+28b=3\\a+2b=\dfrac{4,48}{22,4}=0,2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}a=0,1\\b=0,05\end{matrix}\right.\\ b.V_{O_2\left(đktc\right)}=22,4.\left(2a+3b\right)=22,4.\left(2.0,1+0,05.3\right)=7,84\left(l\right)\\ c.\%V_{CH_4}=\dfrac{a}{a+b}.100\%=\dfrac{0,1}{0,05+0,1}.100\approx66,667\%\\ \Rightarrow\%V_{C_2H_4}\approx33,333\%\)