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\(n_C=\dfrac{1.2}{12}=0.1\left(mol\right)\\ n_S=\dfrac{4}{32}=0.125\left(mol\right)\)
\(2KMnO_4\underrightarrow{t^0}K_2MnO_4+MnO_2+O_2\)
\(C+O_2\underrightarrow{t^0}CO_2\)
\(S+O_2\underrightarrow{t^0}SO_2\)
\(\sum n_{O_2}=n_C+n_S=0.1+0.125=0.225\left(mol\right)\)
\(\Rightarrow n_{KMnO_4}=2n_{O_2}=0.225\cdot2=0.45\left(mol\right)\)
\(m_{KMnO_4}=0.45\cdot158=71.1\left(g\right)\)
\(n_{Ca}=\dfrac{0,4}{40}=0,01\left(mol\right)\)
PTHH: 2Ca + O2 --to--> 2CaO
0,01-->0,005
2KMnO4 --to--> K2MnO4 + MnO2 + O2
0,01<------------------------------0,005
=> \(m_{KMnO_4}=0,01.158=1,58\left(g\right)\)
\(n_{Ca}=\dfrac{0,4}{40}=0,01\left(mol\right)\)
PTHH: 2Ca + O2 --to--> 2CaO
0,01-->0,005
2KClO3 --to,MnO2--> 2KCl + 3O2
\(\dfrac{1}{300}\)<------------------------0,005
=> \(m_{KClO_3}=\dfrac{1}{300}.122,5=\dfrac{49}{120}\left(g\right)\)
a) \(n_{KMnO_4}=\dfrac{15,8}{158}=0,1\left(mol\right)\)
\(PTHH:2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\uparrow\)
(mol)..........0,1................0,05..........0,05......0,05
\(V_{O_2}=0,05.22,4=1,12\left(l\right)\)
b) \(n_{Fe}=\dfrac{1.68}{56}=0,03\left(mol\right)\)
\(PTHH:3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)
(mol).......0,03....0,02.......0,1
\(PTHH:2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\uparrow\)
(mol)..........0,04..............0,02............0,02....0,02
\(m_{KMnO_4}=0,04.158=6,32\left(g\right)\)
\(m_{KMnO_4\left(thựctế\right)}=6,32:95\%\approx6,65\left(g\right)\)
`4P + 5O_2` $\xrightarrow{t^o}$ `2P_2 O_5`
`0,32` `0,4` `0,16` `(mol)`
`a)n_P=[12,4]/31=0,4(mol)`
`n_[O_2]=[8,96]/[22,4]=0,4(mol)`
Có: `[0,4]/4 > [0,4]/5`
`=>O_2` hết, `P` dư
`=>m_[P(dư)]=(0,4-0,32).31=2,48(g)`
`b)m_[P_2 O_5]=0,16.142=22,72(g)`
`c)`
`2KMnO_4` $\xrightarrow{t^o}$ `K_2 MnO_4 +MnO_2 + O_2`
`0,8` `0,4` `(mol)`
`=>m_[KMnO_4]=0,8.158=126,4(g)`
`d)`
`KClO_3` $\xrightarrow[MnO_2]{t^o}$ `KCl + 3/2 O_2`
`4/15` `0,4` `(mol)`
`=>m_[KClO_3]=4/15 . 122,5~~32,67(g)`
Bạn tách ra từng câu nhé!
Bài 3.
\(n_{Fe}=\dfrac{m_{Fe}}{M_{Fe}}=\dfrac{36}{56}=0,6428mol\)
\(3Fe+2O_2\rightarrow\left(t^o\right)Fe_3O_4\)
0,6428 ----- 0,4285 ( mol )
\(2KMnO_4\rightarrow\left(t^o\right)K_2MnO_4+MnO_2+O_2\)
0,857 0,4285 ( mol )
\(m_{KMnO_4}=n_{KMnO_4}.M_{KMnO_4}=0,857.158=135,406g\)
Bài 4.
a.\(n_{Al_2O_3}=\dfrac{m_{Al_2O_3}}{M_{Al_2O_3}}=\dfrac{51}{102}=0,5mol\)
\(4Al+3O_2\rightarrow\left(t^o\right)2Al_2O_3\)
1 0,75 0,5 ( mol )
\(m_{Al}=n_{Al}.M_{Al}=1.27=27g\)
\(V_{O_2}=n_{O_2}.22,4=0,75.22,4=16,8l\)
b.\(2KMnO_4\rightarrow\left(t^o\right)K_2MnO_4+MnO_2+O_2\)
1,5 0,75 ( mol )
\(m_{KMnO_4}=n_{KMnO_4}.M_{KMnO_4}=1,5.158=237g\)
\(2KClO_3\rightarrow\left(t^o\right)2KCl+3O_2\)
0,5 0,75 ( mol )
\(m_{KClO_3}=n_{KClO_3}.M_{KClO_3}=0,5.122,5=61,25g\)
Có lẽ đề cho "Đốt cháy hoàn toàn 5,4 g Al" bạn nhỉ?
a, PT: \(4Al+3O_2\underrightarrow{t^o}2Al_2O_3\)
Ta có: \(n_{Al}=\dfrac{5,4}{27}=0,2\left(mol\right)\)
Theo PT: \(n_{O_2}=\dfrac{3}{4}n_{Al}=0,15\left(mol\right)\)
\(\Rightarrow V_{O_2}=0,15.22,4=3,36\left(l\right)\)
b, PT: \(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\)
Theo PT: \(n_{KMnO_4}=2n_{O_2}=0,3\left(mol\right)\)
\(\Rightarrow m_{KMnO_4}=0,3.158=47,4\left(g\right)\)
a, PTHH: 3Fe+ 2O2--> Fe3O4(đk là t độ)
Theo pt: nFe=3nFe3O4=3* 2,32/232=0,03 mol;
--> mFe cần dùng = 0,03* 56 = 1,68 mol;
Tương tự : nO2 = 2 nFe3O4 =2 * 0,01 =0,02 mol;
--> VO2 cần dùng = 0,02*22,4 =0,448( l);
b, PTHH : 2KMnO4 --> K2MnO4 +MnO2 + O2 (đk là t độ)
--> nKMnO4= 2nO2= 2 * 0,02 =0,04 mol;
--> mKMnO4 cần dùng =6,32 (g)
PTHH:4P+502\(\rightarrow\)2P2O5
Theo PTHH:124 gam P thì cần 160 gam O2
Vậy :62 gam P thì cần 80 gam O2
PTHH:2KMnO4\(\rightarrow\)K2MnO4+MnO2+O2
Theo PTHH:444 gam KMnO4 thì tạo ra 32 gam O2
Vậy:1110 gam KMnO4 thì tạo ra 80 gam 02
Đáp số:Vậy dùng 1110 gam KMnO4 để điều chế được lượng O2 đủ
4P+5O2--to->2P2O5(1)
\(n_P=\frac{62}{31}=2\left(mol\right)\)
\(n_{O_2}=\frac{5}{4}.n_P=\frac{5}{4}.2=2,5\left(mol\right)\)
2KMnO4-to->K2MnO4+MnO2+O2
\(n_{KMnO_4}=2.n_{O_2}=2.2,5=5\left(mol\right)\)
\(m_P=5.158=790\left(g\right)\)
nC= 1.2/12=0.1 mol
C + O2 -to-> CO2
0.1__0.1
2KMnO2 -to-> K2MnO4 + MnO2 + O2
0.2___________________________0.1
mKMnO4= 0.2*158=31.6g
nC= 1.2/12=0.1 mol
C + O2 -to-> CO2
0.1__0.1
2KMnO4 -to-> K2MnO4 + MnO2 + O2
0.2___________________________0.1
mKMnO4= 0.2*158=31.6g