Hỗn hợp khí A gồm N2 và H2 có: dA/N2=0,35
a) Tìm % n2?%H2
b)Tìm %khối lượng của mỗi khí trong hỗn hợp
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a)
\(V_{N_2}=\dfrac{17,92.62,5}{100}=11,2\left(l\right)\)
=> \(n_{N_2}=\dfrac{11,2}{22,4}=0,5\left(mol\right)\)
Gọi số mol O2 là a (mol)
=> nX = 2a (mol)
Có: \(2a+a+0,5=\dfrac{17,92}{22,4}=0,8\)
=> a = 0,1 (mol)
\(\overline{M}_A=\dfrac{0,1.32+0,2.M_X+0,5.28}{0,8}=12,875.2=25,75\left(g/mol\right)\)
=> MX = 17 (g/mol)
=> X là NH3
b) \(\left\{{}\begin{matrix}\%m_{N_2}=\dfrac{0,5.28}{0,5.28+0,2.17+0,1.32}.100\%=67,961\%\\\%m_{O_2}=\dfrac{0,1.32}{0,5.28+0,2.17+0,1.32}.100\%=15,54\%\\\%m_{NH_3}=\dfrac{0,2.17}{0,5.28+0,2.17+0,1.32}.100\%=16,505\%\end{matrix}\right.\)
c) \(n_{H_2}=\dfrac{0,4}{2}=0,2\left(mol\right)\)
\(\overline{M}_B=\dfrac{0,5.28+0,2.17+0,1.32+0,4}{0,5+0,2+0,1+0,2}=21\left(g/mol\right)\)
Tính tỉ khối của B với gì vậy bn :) ?
\(n_{hhA}=\dfrac{4,48}{22,4}=0,2\left(mol\right)\Rightarrow m_{hhA}=0,2.30=6\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}x+y=0,2\\28x+32y=6\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0,2-y\\28.\left(0,2-y\right)+32y=6\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0,1\\y=0,1\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}m_{N_2}=0,1.28=2,8\left(g\right)\\m_{O_2}=6-2,8=3,2\left(g\right)\end{matrix}\right.\)
\(I,M_{hh}=M_{O_2}.0,3125=32.0,3125=10\left(\dfrac{g}{mol}\right)\\ Đặt:n_{N_2}=a\left(\%\right)\\ \Rightarrow\dfrac{28a+2\left(100\%-a\right)}{100\%}=10\\ \Leftrightarrow a\approx30,769\%=\%n_{N_2}=\%V_{N_2}\\ \Rightarrow\%V_{H_2}\approx69,231\%\\ II,Đặt:n_{N_2\left(thêm\right)}=k\left(mol\right)\\ n_{hh}=\dfrac{29,12}{22,4}=1,3\left(mol\right)\\ M_{hh.khí.mới}=M_{O_2}.0,46875=32.0,46875=15\left(\dfrac{g}{mol}\right)\\ \Leftrightarrow\dfrac{\left(k+0,13.0,30769\right).28+2.0,69231}{k+0,13}=15\\ \Leftrightarrow k=\left(ra.âm\right)\)
Nói chung làm được ý 1, anh thấy ý 2 ra âm. Em xem lại đề nha
Bài 1.
Gọi \(\left\{{}\begin{matrix}n_{N_2}=x\left(mol\right)\\n_{H_2}=y\left(mol\right)\end{matrix}\right.\)
\(\dfrac{d_{N_2,H_2}}{M_{O_2}}=0,3125\Rightarrow d_{N_2,H_2}=0,3125\cdot32=10\)
Sơ đồ chéo:
\(N_2\) 28 8
\(10\)
\(H_2\) 2 18
\(\Rightarrow\dfrac{N_2}{H_2}=\dfrac{x}{y}=\dfrac{8}{18}=\dfrac{4}{9}\)\(\Rightarrow9x-4y=0\left(1\right)\)
Mà \(x+y=\dfrac{29,12}{22,4}=1,3\left(2\right)\)
Từ (1) và (2) \(\Rightarrow\left\{{}\begin{matrix}x=0,4\\y=0,9\end{matrix}\right.\)
\(\%V_{N_2}=\dfrac{0,4}{0,4+0,9}\cdot100\%=30,77\%\)
\(\%V_{H_2}=100\%-30,77\%=69,23\%\)
Gọi \(n_{H_2} = a(mol) ; n_{N_2} = b(mol)\)
Coi \(n_{hỗn\ hợp} = 1(mol)\)
Ta có :
\(n_{hỗn\ hợp} = a + b = 1(mol)\\ m_{hỗn\ hợp} = 2a + 28b = 21,5.1 = 21,5(gam)\\ \Rightarrow a = 0,25 ; b = 0,75\)
Vậy :
\(\%V_{H_2} = \dfrac{0,25}{1}.100\% = 25\%\\ \%V_{N_2} = 100\% - 25\% = 75\%\)
a) Gọi số mol N2, H2 là a, b (mol)
Có: \(\overline{M}_A=\dfrac{28a+2b}{a+b}=7,5.2=15\left(g/mol\right)\)
=> 13a = 13b
=> a = b
=> \(\left\{{}\begin{matrix}\%m_{N_2}=\dfrac{28a}{28a+2b}.100\%=93,33\%\\\%m_{H_2}=\dfrac{2b}{28a+2b}.100\%=6,67\%\end{matrix}\right.\)
b) Giả sử A chứa 1 mol N2, 1 mol H2
PTHH: N2 + 3H2 --to,p,xt--> 2NH3
Xét tỉ lệ: \(\dfrac{1}{1}>\dfrac{1}{3}\) => Hiệu suất tính theo H2
Gọi số mol H2 phản ứng là 3a
PTHH: N2 + 3H2 --to,p,xt--> 2NH3
Trc pư: 1 1 0
Pư: a<--3a--------------->2a
Sau pư: (1-a) (1-3a) 2a
=> \(\overline{M}_B=\dfrac{\left(1-a\right).28+\left(1-3a\right).2+17.2a}{\left(1-a\right)+\left(1-3a\right)+2a}=9,375.2=18,75\left(g/mol\right)\)
=> a = 0,2
=> \(H\%=\dfrac{0,2.3}{1}.100\%=60\%\)
\(n_A=1\left(mol\right)\)
\(n_{N_2}=a\left(mol\right),n_{H_2}=b\left(mol\right)\)
\(\Leftrightarrow a+b=1\left(1\right)\)
\(m_A=28a+2b=7.2\left(g\right)\left(2\right)\)
\(\left(1\right)\left(2\right):a=0.2,b=0.8\)
\(\%N_2=20\%,\%H_2=80\%\)
\(n_{N_2\left(pư\right)}=a\left(mol\right)\)
\(N_2+3H_2⇌2NH_3\)
\(0.2......0.8\)
\(a.......3a.........2a\)
\(0.2-a.0.8-3a....2a\)
\(M_B=\dfrac{\left(0.2-a\right)\cdot28+\left(0.8-3a\right)\cdot2+2a\cdot17}{0.2-a+0.8-3a+2a}=9\)
\(\Leftrightarrow a=0.1\)
\(\%N_2=12.5\%\)
\(\%H_2=62.5\%\)
\(\%NH_3=25\%\)
\(H\%=\dfrac{0.1}{0.2}\cdot100\%=50\%\)
Coi $n_A = 1(mol)$
Gọi $n_{N_2} = a ; n_{H_2} = b$
$M_A = 3,6.2 = 7,2$
Ta có:
$a + b = 1$
$28a + 2b = 7,2(a + b)$
Suy ra a = 0,2; b = 0,8
Vậy $\%V_{N_2} = \dfrac{0,2}{1}.100\% = 20% ; \%V_{H_2} = 80\%$
Gọi hiệu suất là a
$N_2 + 3H_2 \xrightarrow{t^o,xt} 2NH_3$
Ta thấy : $n_{N_2} : 1 < n_{H_2} : 3$ nên hiệu suất tính theo $N_2$
$n_{N_2\ pư} = 0,2a(mol)$
Theo PTHH :
$n_{H_2\ pư} = 0,6a(mol) ; n_{NH_3} = 0,4a(mol)$
$m_B = m_A = 7,2(gam)$
$\Rightarrow n_B = \dfrac{7,2}{4,5.2} = 0,8$
Khí B gồm :
$N_2 : 0,2 - 0,2a(mol)$
$H_2 : 0,8 - 0,6a(mol)$
$NH_3 : 0,4a(mol)$
Suy ra : 0,2 - 0,2a + 0,8 - 0,6a + 0,4a = 0,8
Suy ra a = 0,5 = 50%
Vậy B gồm :
$N_2 : 0,1(mol)$
$H_2 : 0,5(mol)$
$NH_3 : 0,2(mol)$
$\%V_{N_2} = \dfrac{0,1}{0,8}.100\% = 12,5\%$
$\%V_{H_2} = \dfrac{0,5}{0,8}.100\% = 62,5\%$
$\%V_{NH_3} = 25\%$
\(a.\)
\(GS:\)
\(n_{hh}=1\left(mol\right)\)
\(Đặt:n_{N_2}=a\left(mol\right),n_{CO_2}=b\left(mol\right)\)
\(\Rightarrow a+b=1\left(1\right)\)
\(m_A=28a+44b=18\cdot2=36\left(2\right)\)
\(\left(1\right),\left(2\right):\)
\(a=b=0.5\)
\(\%m_{N_2}=\dfrac{0.5\cdot28}{0.5\cdot28+0.5\cdot44}\cdot100\%=38.89\%\)
\(\%m_{CO_2}=61.11\%\)
\(b.\)
\(\dfrac{n_{N_2}}{n_{CO_2}}=\dfrac{0.5}{0.5}=\dfrac{1}{1}\)
\(n_{N_2}=n_{CO_2}=\dfrac{1}{2}\cdot n_A=\dfrac{0.2}{2}=0.1\left(mol\right)\)
\(Đặt:n_{CO_2}=x\left(mol\right)\)
\(\overline{M}=\dfrac{0.1\cdot28+0.1\cdot44+44x}{0.2+x}=20\cdot2=40\left(\dfrac{g}{mol}\right)\)
\(\Rightarrow x=0.2\)
\(m_{CO_2\left(cầnthêm\right)}=0.2\cdot44=8.8\left(g\right)\)
\(GS:n_A=1\left(mol\right)\)
\(n_{N_2}=a\left(mol\right),n_{H_2}=b\left(mol\right)\)
\(\Leftrightarrow a+b=1\left(1\right)\)
\(M_A=0.35\cdot28=9.8\left(\dfrac{g}{mol}\right)\)
\(m_A=9.8\cdot1=9.8\left(g\right)\)
\(\Leftrightarrow28a+2b=9.8\left(2\right)\)
\(\left(1\right),\left(2\right):a=0.3,b=0.7\)
\(\%n_{N_2}=\dfrac{0.3}{1}\cdot100\%=30\%\)
\(\%n_{H_2}=70\%\)
\(\%m_{N_2}=\dfrac{0.3\cdot28}{9.6}\cdot100\%=87.5\%\)
\(\%m_{H_2}=12.5\%\)
\(\)
a) Gọi n N2 = a(mol) ; n H2 = b(mol)
Coi n A = 1(mol)
M A = 0,35.28 = 9,8 (g/mol)
Ta có :
a + b = 1
28a + 2b = 9,8.1
Suy ra a = 0,3 ; b = 0,7
%V N2 = 0,3/1 .100% = 30%
%V H2 = 0,7/1 .100% = 70%
b)
%m N2 = 0,3.28/9,8 . 100% = 85,71%
%m H2 = 100%- 85,71% = 14,29%