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\(n_{CH_4}=\dfrac{3,2}{16}=0,2\left(mol\right)\)
PTHH: CH4 + 2O2 --to--> CO2 + 2H2O
0,2--->0,4--------->0,2
\(\rightarrow\left\{{}\begin{matrix}V_{O_2}=0,4.22,4=8,96\left(l\right)\\m_{CO_2}=0,2.44=8,8\left(g\right)\end{matrix}\right.\)
\(n_{Mg}=\dfrac{4,8}{24}=0,2\left(mol\right)\\
pthh:CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)
0,2 0,4 0,4
\(V_{O_2}=0,4.22,4=8,96\left(l\right)\\
m_{H_2O}=0,4.18=7,2\left(g\right)\)
PTHH; CH4 + 2O2 → 2H2O + CO2↑
nCH4=3,2\16=0,2(mol)
Theo PTHH, ta có: nO2=2nCH4=2.0,2=0,4(mol))
⇒VO2=0,4.22,4=8,96(l)
Theo PTHH, ta có:nCO2=nCH4=0,2(mol)
⇒mCO2=0,2.48=9,6(g)
\(n_{CH_4}=\dfrac{32}{16}=2\left(mol\right)\)
\(CH_4+2O_2\underrightarrow{t^0}CO_2+2H_2O\)
\(2...........4.........2\)
\(m_{O_2}=4.\cdot32=128\left(g\right)\)
\(m_{CO_2}=2\cdot44=88\left(g\right)\)
\(d_{\dfrac{CO_2}{kk}}=\dfrac{M_{CO_2}}{M_{kk}}=\dfrac{44}{29}=1.5\)
Khí : CO2 nặng hơn và nặng gấp 1.5 lần không khí.
PTHH: \(CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)
a) Ta có: \(n_{CH_4}=\dfrac{32}{16}=2\left(mol\right)\)
\(\Rightarrow n_{O_2}=4mol\) \(\Rightarrow m_{O_2}=4\cdot32=128\left(g\right)\)
b) Theo PTHH: \(n_{CO_2}=n_{CH_4}=2mol\)
\(\Rightarrow m_{CO_2}=2\cdot44=88\left(g\right)\)
c) Ta có: \(d_{CO_2/kk}=\dfrac{44}{29}\approx1,52\)
Vậy CO2 nặng hơn không khí 1,52 lần
Bài 1 :
\(n_{Na}=\dfrac{m}{M}=0,1\left(mol\right)\)
\(4Na+O_2\rightarrow2Na_2O\)
..0,1....0,025....0,05.......
a, \(V_{O_2}=n.22,4=0,56\left(l\right)\)
b, \(m=m_{Na_2o}=n.M=3,1\left(g\right)\)
Bài 2 :
\(n_{Al}=\dfrac{m}{M}=0,1\left(mol\right)\)
\(4Al+3O_2\rightarrow2Al_2O_3\)
..0,1...0,075...
\(\Rightarrow n_{O_2}=0,075\left(mol\right)\)
Mà : \(\Sigma n_{O_2}=\dfrac{V}{22,4}=0,4\left(mol\right)\)
\(\Rightarrow n_{O_2\left(Mg\right)}=0,4-0,075=0,325\left(mol\right)\)
\(2Mg+O_2\rightarrow2MgO\)
.0,65.....0,325........
\(\Rightarrow m_{Mg}=15,6\left(g\right)\)
\(\Rightarrow m_{hh}=2,7+15,6=18,3\left(g\right)\)
\(\Rightarrow\left\{{}\begin{matrix}\%Al=~14,75\\\%Mg=~85,25\end{matrix}\right.\) %
Bài 3 :
- Gọi số mol Al và Mg lần lượt là x , y
\(4Al+3O_2\rightarrow2Al_2O_3\)
..x....0,75x
\(2Mg+O_2\rightarrow2MgO\)
..y........0,5y...........
Có : \(n_{O_2}=0,75x+0,5y=\dfrac{V}{22,4}=0,1\left(mol\right)\left(I\right)\)
Lại có : \(m_{hh}=m_{Al}+m_{Mg}=27x+24y=3,9\left(II\right)\)
- Giair ( i ) và ( ii ) ta được : \(\left\{{}\begin{matrix}x=0,1\\y=0,05\end{matrix}\right.\) ( mol )
\(\Rightarrow\left\{{}\begin{matrix}\%Al=~69,23\\\%Mg=~30,77\end{matrix}\right.\) %
Vậy ...
B2 :
a)
nCH4 = 3.2/16 = 0.2 (mol)
CH4 + 2O2 -to-> CO2 + 2H2O
0.2____0.4_____0.2
VO2 = 0.4*22.4 = 8.96 (l)
mCO2 = 0.2*44 = 8.8 (g)
B3 :
Oxit axit :
- CO2 : cacbon dioxit
- N2O5 : dinito pentaoxit
- SiO2 : silic dioxit
Oxit bazo :
- Na2O : natri oxit
- CuO : đồng (II) oxit
- Ag2O : Bạc oxit
Chúc em học tốt !!!
a, \(n_{CH_4}=0,2\left(mol\right)\)
PTHH : \(CH_4+2O_2\rightarrow CO_2+2H_2O\)
..............0,2.->...0,4........0,2........
\(\Rightarrow V_{O_2}=0,4.22,4=8,96\left(l\right)\)
b, \(m_{CO_2}=44n_{CO_2}=8,8\left(g\right)\)
Bài 2:
PTHH: \(CH_4+2O_2\underrightarrow{t^o}CO_2+2H_2O\)
Ta có: \(n_{CH_4}=\dfrac{3,2}{16}=0,2\left(mol\right)\)
\(\Rightarrow\left\{{}\begin{matrix}n_{O_2}=0,4mol\\n_{CO_2}=0,2mol\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}V_{O_2}=0,4\cdot22,4=8,96\left(l\right)\\m_{CO_2}=0,2\cdot44=8,8\left(g\right)\end{matrix}\right.\)
a) \(n_{Al_2O_3}=\dfrac{20,4}{102}=0,2\left(mol\right)\)
PTHH: 4Al + 3O2 --to--> 2Al2O3
0,4<--0,3<---------0,2
=> mAl = 0,4.27 = 10,8(g)
b) C1: VO2 = 0,3.22,4 = 6,72(l)
C2: Theo ĐLBTKL: mO2 = 20,4 - 10,8 = 9,6(g)
=> \(n_{O_2}=\dfrac{9,6}{32}=0,3\left(mol\right)=>V_{O_2}=0,3.22,4=6,72\left(l\right)\)
c) Vkk = 6,72 : 20% = 33,6(l)
Bài 1:
a. CH4 + 2O2 ---> 2 H2O + CO2
0,2------------0,4--------------------0,2 (mol)
nCH4=\(\dfrac{3,2}{16}\)=0,2(mol)
=> nO2=0,2*2=0,4 (mol)=> VO2=0,4*22,4=8,96(l)
b. nCO2=0,2 (mol)
=>mCO2=0,2*44=8,8(g)
a/
Áp dụng công thức: \(m=n.M=>n=\dfrac{m}{M}\)
\(=>n_{CH_4}=\dfrac{m_{CH4}}{M_{CH_4}}=\dfrac{3.2}{16}=0.2\left(mol\right)\)
PTHH:
\(CH_4+2O_2\rightarrow2H_2O+CO_2\)
1 2
0.2 x
\(=>x=0.2\cdot2:1=0.4=n_{O_2}\)
\(=>V_{O_2}=0.4\cdot22.4=8.96\left(l\right)\)