Câu 10. Nhiệt phân m gam KClO 3 sau pư thu được 2,688 lít khí O2 (đktc) tìm m, biết hao hụt 20%
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\(CH_4+2O_2\underrightarrow{^{to}}CO_2+2H_2O\\ n_{H_2O}=\dfrac{3,6}{18}=0,2\left(mol\right)\\ n_{CH_4\left(LT\right)}=\dfrac{0,2}{2}=0,1\left(mol\right)\\ n_{CH_4\left(TT\right)}=0,1:\left(100\%-10\%\right)=\dfrac{1}{9}\left(mol\right)\\ V_{CH_4\left(TT\right)}=\dfrac{1}{9}.22,4\approx2,489\left(l\right)\)
câu 5
nKMnO4=\(\dfrac{31,6.98\%}{158}\)=0,196(mol)
2KMnO4−to→K2MnO4+MnO2+O2
nO2(lt)=\(\dfrac{1}{2}\)nKMnO4=0,098(mol)
Vìhaohụt5%
⇒VO2(tt)=0,098.95%.22,4=2,08544(l)
\(n_{KClO_3}=\dfrac{6,125}{122,5}=0,05mol\)
\(2KClO_3\rightarrow\left(t^o,MnO_2\right)2KCl+3O_2\)
0,05 0,075 ( mol )
\(V_{O_2}=0,075.22,4.\left(100\%-10\%\right)=1,68.90\%=1,512l\)
\(n_{KClO_3}=\dfrac{24,5}{122,5}=0,2\left(mol\right)\\ 2KClO_3\underrightarrow{^{to}}2KCl+3O_2\\ n_{O_2\left(LT\right)}=\dfrac{3}{2}.0,2=0,3\left(mol\right)\\ Vì:H=90\%\Rightarrow n_{O_2\left(TT\right)}=90\%.0,3=0,27\left(mol\right)\\ V_{O_2\left(đktc,thực.tế\right)}=0,27.22,4=6,048\left(l\right)\)
\(a,2KMnO_4\xrightarrow{t^o}K_2MnO_4+MnO_2+O_2\\ n_{KMnO_4}=\dfrac{395}{158}=2,5(mol)\\ \Rightarrow n_{O_2}=1,25(mol)\\ \Rightarrow V_{O_2}=1,25.22,4=28(l)\\ \Rightarrow V_{O_2(tt)}=28.85\%=23,8(l)\)
\(b,n_{O_2}=\dfrac{67,2}{22,4}=3(mol)\\ 2KMnO_4\xrightarrow{t^o}K_2MnO_4+MnO_2+O_2\\ \Rightarrow n_{KMnO_4}=6(mol)\\ \Rightarrow m_{KMnO_4}=6.158=948(g)\\ \Rightarrow m_{KMnO_4(tt)}=\dfrac{948}{80\%}=1185(g)\)
a)
\(n_{KClO_3}=\dfrac{24.5}{122.5}=0.2\left(mol\right)\)
\(2KClO_3\underrightarrow{^{^{t^0}}}2KCl+3O_2\)
\(n_{O_2}=\dfrac{3}{2}\cdot0.2=0.3\left(mol\right)\)
\(V_{O_2}=0.3\cdot22.4=6.72\left(l\right)\)
\(n_{O_2}=\dfrac{2.24}{22.4}=0.1\left(mol\right)\)
\(2KMnO_4\underrightarrow{^{^{t^0}}}K_2MnO_4+MnO_2+O_2\)
\(0.2...............................................0.1\)
\(n_{KMnO_4\left(bđ\right)}=\dfrac{0.2}{90\%}=\dfrac{2}{9}\left(mol\right)\)
\(m_{KMnO_4}=\dfrac{2}{9}\cdot158=35.11\left(g\right)\)
2KClO3-to>2KCl+3O2
0,06-----------------0,09 mol
n O2=2,016\22,4=0,09 mol
=>H =0,06.122,5\12,25 .100=60%
\(n_{O_2\left(TT\right)}=\dfrac{2,016}{22,4}=0,09\left(mol\right)\\ n_{KClO_3}=\dfrac{12,25}{122,5}=0,1\left(mol\right)\\ 2KClO_3\underrightarrow{^{to}}2KCl+3O_2\\ n_{O_2\left(LT\right)}=\dfrac{3}{2}.0,1=0,15\left(mol\right)\\ \Rightarrow H=\dfrac{0,09}{0,15}.100=60\%\)
2KClO3-to>2KCl+3O2
0,08--------------------0,12 mol
n O2=2,688\22,4=0,12 mol
H=20%
=>m KClO3tt=0,08.122,5.100\20=49g
\(n_{O_2}=\dfrac{2,688}{22,4}=0,12\left(mol\right)\\ 2KClO_3\underrightarrow{^{to}}2KCl+3O_2\\ n_{KClO_3\left(LT\right)}=\dfrac{2}{3}.0,12=0,08\left(mol\right)\\ Hao.hụt.80\%.Nên:n_{KClO_3\left(TT\right)}=0,08:\left(100\%-20\%\right)=0,1\left(mol\right)\\\Rightarrow m=m_{KClO_3\left(TT\right)}=122,5.0,1=12,25\left(g\right)\)