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a)PTHH:2KClO\(_3\)➞\(^{t^o}\)2KCl+3O\(_2\)
b) n\(_{KClO_3}\)=\(\dfrac{m_{KClO_3}}{M_{KClO_3}}\)=\(\dfrac{12,15}{122,5}\)\(\approx\)0,1(m)
PTHH : 2KClO\(_3\) ➞\(^{t^o}\) 2KCl + 3O\(_2\)
tỉ lệ : 2 2 3
số mol : 0,1 0,1 0,15
V\(_{O_2}\)=n\(_{O_2}\).22,4=0,15.22,4=3,36(l)
c)PTHH : 2Zn + O\(_2\) -> 2ZnO
tỉ lệ : 2 1 2
số mol :0,3 0,15 0,3
m\(_{Zn}\)=n\(_{Zn}\).M\(_{Zn}\)=0,3.65=19,5(g)
a)
\(n_{Mg} = \dfrac{3,6}{24} = 0,15(mol)\\ 2Mg + O_2 \xrightarrow{t^o} 2MgO\\ n_{O_2} = \dfrac{1}{2}n_{Mg} = 0,075(mol)\\ \Rightarrow V_{O_2} = 0,075.22,4 = 1,68(lít)\)
b)
\(2KClO_3 \xrightarrow{t^o,MnO_2} 2KCl + 3O_2\\ n_{KClO_3} = \dfrac{2}{3}n_{O_2} = \dfrac{2}{3}.0,075 = 0,05(mol)\\ \Rightarrow m_{KClO_3} = 0,05.122,5 = 6,125(gam)\)
Câu 3.
a.b.\(n_{KClO_3}=\dfrac{24,5}{122,5}=0,2mol\)
\(2KClO_3\rightarrow\left(t^o,MnO_2\right)2KCl+3O_2\)
0,2 0,3 ( mol )
\(V_{O_2}=0,3.22,4=6,72l\)
c.\(n_{Al}=\dfrac{5,4}{27}=0,2mol\)
\(4Al+3O_2\rightarrow\left(t^o\right)2Al_2O_3\)
0,2 < 0,3 ( mol )
0,2 0,1 ( mol )
\(m_{Al_2O_3}=0,1.102=10,2g\)
Câu 4.
a.b.
\(n_{KClO_3}=\dfrac{12,25}{122,5}=0,1mol\)
\(2KClO_3\rightarrow\left(t^o,MnO_2\right)2KCl+3O_2\)
0,1 0,15 ( mol )
\(V_{O_2}=0,15.22,4=3,36l\)
c.\(n_{Fe}=\dfrac{8,4}{56}=0,15mol\)
\(3Fe+2O_2\rightarrow\left(t^o\right)Fe_3O_4\)
0,15 < 0,15 ( mol )
0,15 0,05 ( mol )
\(m_{Fe_3O_4}=0,05.232=11,6g\)
= 
a.\(n_{KClO_3}=\dfrac{m_{KClO_3}}{M_{KClO_3}}=\dfrac{12,25}{122,5}=0,1mol\)
\(2KClO_3\rightarrow\left(t^o\right)2KCl+3O_2\)
2 2 3 ( mol )
0,1 0,15
\(V_{O_2}=n_{O_2}.22,4=0,15.22,4=3,36l\)
b.\(V_{kk}=V_{O_2}.5=3,36.5=16,8l\)
c.\(n_{Fe}=\dfrac{m_{Fe}}{M_{Fe}}=\dfrac{28}{56}=0,5mol\)
\(3Fe+2O_2\rightarrow\left(t^o\right)Fe_3O_4\)
3 2 1 ( mol )
0,5 > 0,15 ( mol )
0,225 0,15 ( mol )
\(m_{Fe\left(du\right)}=n_{Fe\left(du\right)}.M_{Fe}=\left(0,5-0,225\right).56=15,4g\)
Theo gt ta có: $n_{Mg}=0,15(mol)$
a, $2Mg+O_2\rightarrow 2MgO$
Ta có: $n_{O_2}=0,5.n_{Mg}=0,075(mol)\Rightarrow V_{O_2}=1,68(l)$
b, $2KClO_3\rightarrow 2KCl+3O_2$ (đk: nhiệt độ, MnO2)
Ta có: $n_{KClO_3}=\frac{2}{3}.n_{O_2}=0,05(mol)\Rightarrow m_{KClO_3}=6,125(g)$
\(n_{Mg}=\dfrac{3.6}{24}=0.15\left(mol\right)\)
\(2Mg+O_2\underrightarrow{t^0}2MgO\)
\(0.15......0.075......0.15\)
\(V_{O_2}=0.075\cdot22.4=1.68\left(l\right)\)
\(2KClO_3\underrightarrow{t^0}2KCl+3O_2\)
\(0.05.......................0.075\)
\(m_{KClO_3}=0.05\cdot122.5=6.125\left(g\right)\)
\(n_{KClO_3\left(bd\right)}=\dfrac{55,125}{122,5}=0,45\left(mol\right)\)
=> \(n_{KClO_3\left(pư\right)}=\dfrac{0,45.85}{100}=0,3825\left(mol\right)\)
PTHH: 2KClO3 --to,MnO2--> 2KCl + 3O2
0,3825------------------->0,57375
=> \(V_{O_2}=0,57375.22,4=12,852\left(l\right)\)
nKClO3= 49/122,5=0,4(mol)
a) PTHH: 2 KClO3 -to-> 2 KCl + 3 O2
b) nO2=3/2 . nKClO3= 3/2 . 0,4= 0,6(mol)
=> V(O2,dktc)=0,6 x 22,4= 13,44 (l)
cho mik hỏi tại sao nO2 lại ra là 3/2 mik ko hiểu chỗ này