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\(n_{Fe}=\dfrac{16,8}{56}=0,3\left(mol\right)\\ a,3Fe+2O_2\rightarrow\left(t^o\right)Fe_3O_4\\ b,n_{O_2}=\dfrac{2}{3}.0,3=0,2\left(mol\right)\\ \Rightarrow V_{O_2\left(đktc\right)}=0,2.22,4=4,48\left(l\right)\\ c,n_{Fe_3O_4}=\dfrac{0,3}{3}=0,1\left(mol\right)\\ \Rightarrow m_{Fe_3O_4}=0,1.232=23,2\left(g\right)\)
a) 3Fe + 2O2 
Fe3O4
b) nFe = \(\dfrac{8,4}{56}\)= 0,15 mol
nFe3O4 = \(\dfrac{11,6}{232}\) = 0,05 mol
Ta thấy \(\dfrac{nFe}{3}\)= \(\dfrac{nFe_3O_4}{1}\)=> Fe phản ứng hết
<=> nO2 cần dùng = \(\dfrac{2nFe}{3}\)= 0,1 mol
<=> mO2 cần dùng = 0,1.32 = 3,2 gam
c) Oxi chiếm thể tích bằng 1/5 thể tích không khí.
Mà V O2 = 0,1.22,4 = 2,24 lít => V không khí = 2,24 . 5 = 11,2 lít
a. \(n_{Fe}=\dfrac{16,8}{56}=0,3\left(mol\right)\)
PTHH : 3Fe + 2O2 -to> Fe3O4
0,3 0,2 0,1
b. \(m_{Fe_3O_4}=0,1.232=23,2\left(g\right)\)
c. \(V_{O_2}=0,2.22,4=4,48\left(l\right)\)
a \(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)
b \(\Rightarrow n_{Fe}=\dfrac{16,8}{56}=0,3mol\) \(\Rightarrow n_{Fe_3O_4}=\dfrac{1}{3}n_{Fe}=0,1mol\Rightarrow m_{Fe_3O_4}=0,1\cdot232=2,32g\)
c \(\Rightarrow n_{O_2}=\dfrac{2}{3}n_{Fe}=0,2mol\Rightarrow V_{O_2}=0,2\cdot22,4=4,48l\)
\(n_{Fe}=\dfrac{16,8}{56}=0,3mol\)
\(3Fe+2O_2\rightarrow\left(t^o\right)Fe_3O_4\)
0,3 0,2 0,1 ( mol )
\(\left\{{}\begin{matrix}m_{O_2}=0,2.32=6,4g\\V_{O_2}=0,2.22,4=4,48l\end{matrix}\right.\)
\(m_{Fe_3O_4}=0,1.232=23,2g\)
REFER
a)3 Fe+2O2--->Fe3O4
b) Ta có
n Fe=16,8/56=0,3(mol)
Theo pthh
n O2=2/3n Fe=0,2(mol)
V O2=0,2.22,4=4,48(l)
c) Cách 1
Áp dụng định luật bảo toàn khối lượng ta có
m Fe3O4=m Fe+m O2
=16,8+0,2.32=23,2(g)
Cách 2
Theo pthh
n Fe3O4=1/3n Fe=0,1(mol)
m Fe3O4=0,1.232=23,2(g)
\(a/3Fe+2O_2\xrightarrow[]{t^0}Fe_3O_4\\ b/n_{Fe}=\dfrac{1,4}{56}=0,025mol\\ n_{O_2}=\dfrac{0,025.2}{3}=\dfrac{0,05}{3}mol\\ V_{O_2}=\dfrac{0,05}{3}\cdot22,4\approx0,37l\\ c/C_1\\ n_{Fe_3O_4}=\dfrac{0,025}{3}mol\\ m_{Fe_3O_4}=\dfrac{0,025}{3}\cdot232\approx1,93g\\ C_2\\ m_{O_2}=\dfrac{0,05}{3}\cdot32\approx0,53g\\ BTKL:m_{Fe}+m_{O_2}=m_{Fe_3O_4}\\ \Rightarrow m_{Fe_3O_4}=1,4+0,53=1,93g\)
a)
\(b)n_{Fe_3O_4} = \dfrac{6,96}{232} = 0,03(mol)\\ 3Fe + 2O_2 \xrightarrow{t^o}Fe_3O_4\\ n_{Fe} = 3n_{Fe_3O_4} = 0,09(mol)\\ m_{Fe} = 0,09.56 = 5,04(gam)\\ c) n_{O_2} = 2n_{Fe_3O_4} = 0,06(mol)\\ V_{O_2} = 0,06.22,4 = 1,344(lít)\\ d) 2KMnO_4 \xrightarrow{t^o} K_2MnO_4 + MnO_2 + O_2\\ n_{KMnO_4} = 2n_{O_2} = 0,12(mol)\\ m_{KMnO_4} = 0,12.158 = 18,96(gam)\)
\(n_{Fe_3O_4}=\dfrac{6.96}{232}=0.03\left(mol\right)\)
\(3Fe+2O_2\underrightarrow{t^0}Fe_2O_3\)
\(0.09.....0.06.......0.03\)
\(m_{Fe}=0.09\cdot56=5.04\left(g\right)\)
\(V_{O_2}=0.06\cdot22.4=1.344\left(l\right)\)
\(2KMnO_4\underrightarrow{t^0}K_2MnO_4+MnO_2+O_2\)
\(0.12...............................................0.06\)
\(m_{KMnO_4}=0.12\cdot158=18.96\left(g\right)\)
n Fe3O4=\(\dfrac{13,92}{232}\)=0,06 mol
3Fe + 2O2 -to--> Fe3O4
0,18------0,12-------0,06
=>m Fe=0,18.56=10,08g
=>VO2=0,12.22,4=2,688l
2KMnO4-to>K2MnO4+MnO2+O2
0,24-------------------------------------0,12
=>m KMnO4=0,24.158=37,92g
nFe3O4 = 13,92 : 160= 0,087 (mol)
pthh : 3Fe + 2O2 -t--> Fe3O4
0,087->0,058-->0,029 (mol)
=> mFe = 0,029 . 56 = 1,624 (g)
=> VO2 = 0,058 . 22,4 = 1,2992 (L)
pthh : 2KMnO4 -t--> K2MnO4 + MnO2 + O2
0,116<------------------------------0,058 (mol)
=> mKMnO4 = 0,116 . 158 = 18,328 (g)
a, \(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)
b, \(n_{Fe}=\dfrac{16,8}{56}=0,3\left(mol\right)\)
Theo PT: \(n_{O_2}=\dfrac{2}{3}n_{Fe}=0,2\left(mol\right)\Rightarrow V_{O_2}=0,2.22,4=4,48\left(l\right)\)
\(n_{Fe_3O_4}=\dfrac{1}{3}n_{Fe}=0,1\left(mol\right)\Rightarrow m_{Fe_3O_4}=0,1.232=23,2\left(g\right)\)
c, \(n_{CuO}=\dfrac{16}{80}=0,2\left(mol\right)\)
PT: \(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)
Xét tỉ lệ: \(\dfrac{0,2}{1}< \dfrac{0,3}{1}\), ta được H2 dư.
Theo PT: \(n_{Cu}=n_{CuO}=0,2\left(mol\right)\Rightarrow m_{Cu}=0,2.64=12,8\left(g\right)\)
\(n_{Fe}=\dfrac{5.6}{56}=0.1\left(mol\right)\)
\(3Fe+2O_2\underrightarrow{^{^{t^0}}}Fe_3O_4\)
\(0.1.......\dfrac{1}{15}...\dfrac{1}{30}\)
\(m_{Fe_3O_4}=\dfrac{1}{30}\cdot232=7.73\left(g\right)\)
\(V_{O_2}=\dfrac{1}{15}\cdot22.4=1.493\left(l\right)\)