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a.\(n_{CH_4}=\dfrac{V_{CH_4}}{22,4}=\dfrac{11,2}{22,4}=0,5mol\)
\(CH_4+2O_2\rightarrow\left(t^o\right)CO_2+2H_2O\)
0,5 1 0,5 ( mol )
\(V_{kk}=V_{O_2}.5=\left(1.22,4\right).5=112l\)
b.\(n_{NaOH}=0,5.0,5=0,25mol\)
\(NaOH+CO_2\rightarrow NaHCO_3\)
0,25 < 0,5 ( mol )
0,25 0,25 ( mol )
\(m_{NaHCO_3}=0,25.84=21g\)
CH4+2O2-to>CO2+2H2O
0,5-----1----------0,5 mol
n CH4=\(\dfrac{11,2}{22,4}\)=0,5 mol
=>Vkk=1.22,4.5=112l
NaOH+CO2->NaHCO3
0,25------0,25-------0,25
n NaOH=0,5.0,5=0,25 mol
=>Tạo ra muối axit, CO2 dư
=>m NaHCO3=0,25.84=21g
Bài 7:
Ta có: \(\left\{{}\begin{matrix}n_{CO_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\\n_{NaOH}=0,2\cdot1=0,2\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\) Tạo 2 muối
PTHH: \(CO_2+2NaOH\rightarrow Na_2CO_3+H_2O\)
a_______2a__________a (mol)
\(CO_2+NaOH\rightarrow NaHCO_3\)
b_______b__________b (mol)
Ta lập HPT: \(\left\{{}\begin{matrix}a+b=0,15\\2a+b=0,2\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}a=0,05\\b=0,1\end{matrix}\right.\)
Mặt khác: \(m_{dd}=m_{CO_2}+m_{ddNaOH}=0,15\cdot44+200\cdot1,25=256,6\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{Na_2CO_3}=\dfrac{0,05\cdot106}{256,6}\cdot100\%\approx2,1\%\\C\%_{NaHCO_3}=\dfrac{0,1\cdot72}{256,6}\cdot100\%\approx2,8\%\end{matrix}\right.\)
Bài 8:
PTHH: \(RCO_3+2HNO_3\rightarrow R\left(NO_3\right)_2+CO_2\uparrow+H_2O\)
Giả sử \(n_{RCO_3}=1\left(mol\right)\) \(\Rightarrow\left\{{}\begin{matrix}n_{HNO_3}=2\left(mol\right)\\n_{R\left(NO_3\right)_2}=1\left(mol\right)=n_{CO_2}\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}m_{ddHNO_3}=\dfrac{2\cdot63}{20\%}=630\left(g\right)\\m_{R\left(NO_3\right)_2}=R+124\left(g\right)\\m_{CO_2}=44\left(g\right)\end{matrix}\right.\) \(\Rightarrow C\%_{R\left(NO_3\right)_2}=\dfrac{124+R}{R+60+630-44}=0,26582\)
\(\Leftrightarrow R=65\) (Kẽm) \(\Rightarrow\) CTHH của muối cacbonat là ZnCO3
PTHH: \(Na_2CO_3+2CH_3COOH\rightarrow2CH_3COONa+H_2O+CO_2\uparrow\)
Tính theo sản phẩm
Ta có: \(\left\{{}\begin{matrix}\Sigma n_{CH_3COOH}=\dfrac{160\cdot15\%}{60}=0,4\left(mol\right)\\n_{CO_2}=\dfrac{2,24}{22,4}=0,1\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}n_{CH_3COOH\left(dư\right)}=0,2\left(mol\right)=n_{CH_3COONa}\\n_{Na_2CO_3}=0,1\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}m_{Na_2CO_3}=0,1\cdot106=10,6\left(g\right)\\m_{CH_3COONa}=0,2\cdot82=16,4\left(g\right)\\m_{CH_3COOH\left(dư\right)}=0,2\cdot60=12\left(g\right)\\m_{CO_2}=0,1\cdot44=4,4\left(g\right)\end{matrix}\right.\)
Mặt khác: \(m_{dd\left(sau.p/ứ\right)}=m_{Na_2CO_3}+m_{ddAxit}-m_{CO_2}=166,2\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{CH_3COONa}=\dfrac{16,4}{166,2}\cdot100\%\approx9,87\%\\C\%_{CH_3COOH\left(dư\right)}=\dfrac{12}{166,2}\cdot100\%\approx7,22\%\end{matrix}\right.\)
Ta có: \(\left\{{}\begin{matrix}n_{CO_2}=0,1\left(mol\right)\\n_{NaOH}=0,5\cdot0,3=0,15\left(mol\right)\end{matrix}\right.\) \(\Rightarrow\) Tạo 2 muối
PTHH: \(CO_2+NaOH\rightarrow NaHCO_3\)
a_______a__________a (mol)
\(CO_2+2NaOH\rightarrow Na_2CO_3+H_2O\)
b_______2b_________2b (mol)
Ta lập được HPT \(\left\{{}\begin{matrix}a+b=0,1\\a+2b=0,15\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}a=0,05\\b=0,05\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}m_{NaHCO_3}=0,05\cdot84=4,2\left(g\right)\\m_{Na_2CO_3}=0,05\cdot106=5,3\left(g\right)\end{matrix}\right.\)