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ta có PTHH: 2KClO3=>2KCl + 3O2
\(\frac{a}{122,5}\)------->\(\frac{a}{122,5}\).74,5-> \(\frac{3a}{2}\).22,4
2KMnO4=>K2MnO4+ MnO2+ O2
\(\frac{b}{158}\)------->\(\frac{b}{2.158}.197\)->\(\frac{b}{2.158}.87\)-> \(\frac{b}{2}.22,4\)
từ 2PT trên ta có : \(\frac{a}{122,5}.74,5=\frac{b}{2.158}.197+\frac{b}{2.158}.87\)
=> a/b=1,78
b) tỉ lệ phản ứng: \(\frac{3a}{2}.22,4:\frac{b}{2}.22,4=\frac{3a}{b}=4,43\)
a) 2KClO3------> 2KCl+ 3O2
công thức tính khối lượng:
m KClo3= m KCl+ m O2
b) m KCLo3= 14,9+9,6=24,5g
a) 2KClO3 \(\underrightarrow{t^o}\) 2KCl + 3O2
mol \(\dfrac{a}{122,5}\rightarrow\dfrac{a}{122,5}\dfrac{3a}{245}\)
2KMnO4 \(\underrightarrow{t^o}\) K2MnO4 + MnO2 + O 2
mol \(\dfrac{b}{158}\rightarrow\dfrac{b}{316}\dfrac{b}{316}\dfrac{b}{316}\)
\(74,5.\dfrac{a}{122,5}=197.\dfrac{b}{316}+87.\dfrac{b}{316}\)
⇔ \(\dfrac{74,5a}{122,5}=\dfrac{71b}{79}\)
⇒ \(\dfrac{a}{b}=\dfrac{71.122,5}{74,5.79}\approx1,478\)
b) \(\dfrac{3a}{245}:\dfrac{b}{316}=\dfrac{3a.316}{245.b}=\dfrac{948}{245}.\dfrac{a}{b}=\dfrac{948}{245}.1,478\approx5,72\)
nKClO3=a/122,5(mol)
nKMnO4=b/158(mol)
\(2KClO3\rightarrow2KCl+3O2\)(1)
a/122,5____a/122,5____1,5a/122,5
\(2KMnO4\rightarrow K2MnO4+MnO2+O2\)(2)
b/158_______b/136_________b/136___b/136
Ta có: 74.a/122,5=197.b/136+87.b/136
Giải ra:
=>a/b~1,478
b)
nO2(1)/nO2(2)=\(\dfrac{1,5a}{\dfrac{122,5}{\dfrac{b}{316}}}\)=\(\dfrac{948}{245}.\dfrac{a}{b}=\dfrac{948}{245}.1,478=5,72\)
a) \(n_{Fe_2O_3}=\frac{32}{160}=0,2\left(mol\right)\)
PTHH : \(Fe_2O_3+3H_2-t^o->2Fe+3H_2O\)
Theo pthh : \(n_{H_2}=3n_{Fe_2O_3}=0,6\left(mol\right)\)
=> \(V_{H_2}=0,6\cdot22,4=13,44\left(l\right)\)
b) Theo pthh : \(n_{H_2O}=n_{H_2}=0,6\left(mol\right)\)
=> \(m_{H_2O}=0,6\cdot18=10,8\left(g\right)\)
c) Theo pthh : \(n_{Fe}=2n_{Fe_2O_3}=0,4\left(mol\right)\)
=> \(m_{Fe}=0,4\cdot56=22,4\left(g\right)\)
a) \(2KClO_3--to->2KCl+3O_2\left(1\right)\)
1,6___________________1,6____ 2,4
=>\(n_{O_2}=\dfrac{53,76}{22,4}=2,4\left(mol\right)\)
Đặt a là số mol KClO3 bđ
=> (a-1,6).122,5+1,6.74,5=168,2
=>a=2
=>\(m_{KClO_3\left(bđ\right)}=2.122,5=245\left(g\right)\)
=>\(m_{KClO_3\left(sau\right)}=1,6.122,5=196\left(g\right)\)
=>\(\%m_{KClO_3}=\dfrac{196}{245}.100=80\%\)
b) \(2KMnO_4--to->K_2MnO_4+MnO_2+O_2\left(2\right)\)
4,8_____________________________________ 2,4
=>\(m_{KMnO_4\left(pứ\right)}=4,8.158=758,4\left(g\right)\)
=>\(m_{KMnO_1\left(bđ\right)}=\dfrac{758,4.100}{90}=842,67\left(g\right)\)
2KClO3\(\rightarrow\) 2KCl + 3O2
\(\text{nO2(đktc) = 53,76 : 22,4 = 2,4 (mol)}\)
\(\rightarrow\) mO2 = nO2.MO2 = 2,4.32 = 76,8 (g)
BTKL ta có: mKClO3 bđ = m rắn + mO2 = 168,2 + 76,8=245 (g)
b) 2KMnO4\(\rightarrow\) K2MnO4 + MnO2 + O2
4,8 ________________________2,4 (mol)
Theo PTHH: \(\text{nKMnO4 = 2nO2 = 2.2,4 = 4,8 (mol)}\)
\(\rightarrow\) mKMnO4 lí thuyết = 4,8.158 = 758,4 (g)
Vì %H = 90% nên
\(\text{mKMnO4 thực tế cần lấy = mKMnO4 lí thuyết.100%:90% = 758,4.100%:90%= 482,67 (g)}\)
a,\(2KMnO_4\underrightarrow{^{to}}K_2MnO_4+MnO_2+O_2\)
a___________1/2a_______1/2a_______
\(2KClO_3\underrightarrow{^{to}}2KCl+3O_2\)
b___________b______
\(m_{Cr}=m_{K2MnO4}+m_{MnO2}+m_{KCl}\)
\(\Leftrightarrow197.\frac{1}{2}a+87.\frac{1}{2}a+74,5b\)
\(\Rightarrow142a+74,5b\)
b,\(m_{K2MnO4}+m_{MnO2}=m_{KCl}\)
\(\Leftrightarrow142a=74,5b\)
\(\Rightarrow\frac{a}{b}=\frac{74,5}{142}=\frac{149}{284}\)