\(n_{KMnO_4}=\dfrac{15.8}{158}=0.1\left(mol\right)\)

\(2KMnO_4\underrightarrow{t^0}K_2MnO_4+MnO_2+O_2\)

\(n_{O_2}=\dfrac{0.1}{2}=0.05\left(mol\right)\)

\(V_{O_2}=0.05\cdot22.4=1.12\left(l\right)\)

\(b.\)

\(n_P=\dfrac{6.2}{31}=0.2\left(mol\right)\)

\(4P+5O_2\underrightarrow{t^0}2P_2O_5\)

\(4.........5\)

\(0.2........0.05\)

\(LTL:\dfrac{0.2}{4}>\dfrac{0.05}{5}\Rightarrow Pdư\)

\(m_{P\left(dư\right)}=\left(0.2-0.04\right)\cdot31=4.96\left(g\right)\)

PTHH:2KMnO4--- K2MnO4+MnO2 +O2

ADCT nKmno4=15,8/158=0,1 mol 

a, theo pt có nO2/nKmno4= 1/2 

nO2=0,05 mol 

ADCT V=n*22,4 

VO2=0,05*22,4 =1,12 l

b, PTHH: 5O2+4P---2P2O5

ADCTnP=6,2/31=0,2 mol 

Theo pt 

nO2/5=0,01     bé hơn     nP/4=0,05 

P dư 

theo pt nP(pư)/nO2=4/5 

nP(p/ư)=0,04 mol 

nP(dư)=0,05-0,04 =0,01 mol

ADCT:m=n*M

mP(dư)=0,01*31=0,31g

\(n_{Zn}=\dfrac{48,75}{65}=0,75mol\)

\(Zn+2HCl\rightarrow ZnCl_2+H_2\)

0,75                                0,75  ( mol )

\(V_{H_2}=0,75.22,4=16,8l\)

\(Fe_3O_4+4H_2\rightarrow\left(t^o\right)3Fe+4H_2O\)

                 0,75          0,5625                ( mol )

\(m_{Fe}=0,5625.56=31,5g\)

Zn+2HCl->ZnCl2+H2

0,75-------------------0,75

Fe3O4+4H2-to>3Fe+4H2O

            0,75--------0,5625g 

n Zn=\(\dfrac{48,75}{65}\)=0,75 mol

=>VH2=0,75.22,4=16,8l

=>m Fe=0,5625.56=31,5g

a/ Ta có: \(n_{KClO_3}=\dfrac{12.25}{122.5}=0.1\left(mol\right)\)

PTHH:

\(2KClO_3\underrightarrow{t^o}2KCl+3O_2\uparrow\)

2                              3

0.1                           x

\(=>x=\dfrac{0.1\cdot3}{2}=0.15=n_{O_2}\)

\(=>V_{O_2}=0.15\cdot22.4=3.36\left(l\right)\)

PTHH: \(KClO_3\underrightarrow{t^o}KCl+\dfrac{3}{2}O_2\)

a) Ta có: \(n_{KClO_3}=\dfrac{12,25}{122,5}=0,1\left(mol\right)\)

\(\Rightarrow n_{O_2}=0,15\left(mol\right)\) \(\Rightarrow V_{O_2}=0,15\cdot22,4=3,36\left(l\right)\)

b) PTHH: \(3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\)

Ta có: \(n_{Fe}=\dfrac{11,2}{56}=0,2\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,2}{3}< \dfrac{0,15}{2}\) \(\Rightarrow\) Oxi còn dư, Fe p/ứ hết

\(\Rightarrow n_{Fe_3O_4}=\dfrac{1}{15}\left(mol\right)\) \(\Rightarrow m_{Fe_3O_4}=\dfrac{1}{15}\cdot232\approx15,47\left(g\right)\)

\(n_{KClO_3}=\dfrac{m_{KClO_3}}{M_{KClO_3}}=\dfrac{12,25}{122,5}=0,1\left(mol\right)\\ PTHH:2KClO_3\underrightarrow{t^o}2KCl+3O_2\\ n_{O_2}=\dfrac{3}{2}n_{KClO_3}=\dfrac{3}{2}\cdot0,1=0,15\left(mol\right)\\ V_{O_2\left(ĐKTC\right)}=n_{O_2}\cdot22,4=0,15\cdot22,4=3,36\left(l\right)\\ n_{Fe}=\dfrac{m_{Fe}}{M_{Fe}}=\dfrac{11,2}{56}=0,2\left(mol\right)\\ PTHH:3Fe+2O_2\underrightarrow{t^o}Fe_3O_4\\ \dfrac{n_{Fe}}{n_{O_2}}=2>\dfrac{3}{2}\Rightarrow Fe\text{ dư, bài toán tính theo lượng }O_2\\ m_{Fe_3O_4}=n_{Fe_3O_4}\cdot M_{Fe_3O_4}=0,075\cdot232=17,4\left(g\right)\)

$n_{Al} = \dfrac{5,4}{27} = 0,2(mol)$
\(4Al+3O_2\xrightarrow[]{t^o}2Al_2O_3\)

0,2         0,15            0,1                (mol)

$V_{O_2} = 0,15.22,4 = 3,36(lít)$
$m_{Al_2O_3} =0,1.102 = 10,2(gam)$

nAL=54:27=2 mol

nAL2O3=1mol

PTHH: 4Al+3O2=>2Al2O3

               2                  1

              2->3/2<==3/2

=> mO2=1,5.32=48g

=> V O2=1,5.22,4=33,6l   

16 nCO2=0,2mol

PTHH: 2CO+O2=>2CO2

         0,2<--0,1<---0,2

=> mO2=0,2.32=6,4g

=> khối lượng Oxi phản ứng với H2 là :

9,6-6,4=3,2g

=> nH2O=3,2:32=0,1mol

PTHH: 2H+O2=>H2O

b)

           0,2<-0,1<-0,2

=> mH2=2.0,2=0,4g

mCO =0,2.28=5,6g

=> m hh=5,6+0,4=6g

CuO+H2-to--->Cu+H2O 

0,6----0,6
nCuO =48/80=0,6 (mol)
==>VH2 =0,6×22,4=13.44(l)

17.

\(n_{Fe}=\dfrac{5,6}{56}=0,1mol\)

\(m_{H_2SO_4}=200.19,6\%=39,2g\)

\(n_{H_2SO_4}=\dfrac{39,2}{98}=0,4mol\)

\(Fe+H_2SO_4\rightarrow FeSO_4+H_2\)

0,1 <   0,4                                 ( mol )

0,1       0,1              0,1        0,1   ( mol )

\(V_{H_2}=0,1.22,4=2,24l\)

Chất còn dư là H2SO4

\(m_{H_2SO_4\left(dư\right)}=\left(0,4-0,1\right).98=29,4g\)

\(\left\{{}\begin{matrix}m_{FeSO_4}=0,1.152=15,2g\\m_{H_2}=0,1.2=0,2g\end{matrix}\right.\)

\(m_{ddspứ}=5,6+200-0,1.2=205,4g\)

\(\left\{{}\begin{matrix}C\%_{FeSO_4}=\dfrac{15,2}{205,4}.100=7,4\%\\C\%_{H_2}=\dfrac{0,2}{205,4}.100=0,09\%\\C\%_{H_2SO_4\left(dư\right)}=\dfrac{29,4}{205,4}.100=14,31\%\end{matrix}\right.\)

\(n_{Fe}=\dfrac{5,6}{56}=0,1\left(mol\right)\)
\(m_{H_2SO_4}=\dfrac{200.19,6}{100}=39,2\left(g\right)\)
\(n_{H_2SO_4}=\dfrac{39,2}{98}=0,4\left(mol\right)\)
pthh : \(Fe+H_2SO_4->FeSO_4+H_2\)
 LTL: 
\(\dfrac{0,1}{1}< \dfrac{0,4}{1}\)
=> H2SO4 dư 
=> \(n_{H_2}=0,1mol\)
=> \(V_{H_2}=0,1.22,4=2,24\left(L\right)\)
theo pthh :\(n_{H_2SO_4\left(p\text{ư}\right)}=n_{Fe}=0,1\left(mol\right)\)
=> \(n_{H_2SO_4\left(d\right)}=0,4-0,1=0,3\left(mol\right)\)
=> \(m_{H_2SO_4}=98.0,3.29,4\left(g\right)\)
ta có mdd =5,6+39,2 = 44,8 (g)
\(C\%=\dfrac{5,6}{44,8}.100\%=12,55\)

PTHH: \(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\uparrow\)

            \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)

Ta có: \(\left\{{}\begin{matrix}n_{O_2}=\dfrac{1}{2}\cdot\dfrac{31,6}{158}\cdot50\%=0,05\left(mol\right)\\n_P=\dfrac{24,8}{31}=0,8\left(mol\right)\end{matrix}\right.\)

Xét tỉ lệ: \(\dfrac{0,8}{4}>\dfrac{0,05}{5}\) \(\Rightarrow\) Photpho còn dư, Oxi p/ứ hết

\(\Rightarrow n_{P_2O_5}=0,02\left(mol\right)\) \(\Rightarrow m_{P_2O_5}=0,02\cdot142=2,84\left(g\right)\)

PT: \(2KMnO_4\underrightarrow{t^o}K_2MnO_4+MnO_2+O_2\)

Ta có: \(n_{KMnO_4}=\dfrac{31,6}{158}=0,2\left(mol\right)\)

Theo PT: \(n_{O_2\left(LT\right)}=\dfrac{1}{2}n_{KMnO_4}=0,1\left(mol\right)\)

Mà:  H% = 50%

\(\Rightarrow n_{O_2\left(TT\right)}=0,1.50\%=0,05\left(mol\right)\)

Ta có: \(n_P=\dfrac{24,8}{31}=0,8\left(mol\right)\)

PT: \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)

Xét tỉ lệ: \(\dfrac{0,8}{4}>\dfrac{0,05}{5}\), ta được P dư.

Theo PT: \(n_{P_2O_5}=\dfrac{2}{5}n_{O_2}=0,02\left(mol\right)\)

\(\Rightarrow m_{P_2O_5}=0,02.142=2,84\left(g\right)\)

Bạn tham khảo nhé!

\(KMnO_4--t^o->K_2MnO_4+MnO_2+O_2\)

158                                                              32

31,6                                                             \(x\)

Với \(H=50\%\) \(\Rightarrow x=\dfrac{31,6.32}{158}.50\%=3,2\left(g\right)\)

\(4P+5O_2--t^o->2P_2O_5\)

124      160

\(y\)           3,2

\(\Rightarrow y=\dfrac{124.3,2}{160}=2,48\left(g\right)\)

\(n_{KMnO_4} = \dfrac{31,6}{158} = 0,2(mol) \Rightarrow n_{KMnO_4\ pư} = 0,2.50\% = 0,1(mol)\\ 2KMnO_4 \xrightarrow{t^o} K_2MnO_4 + MnO_2 + O_2\\ n_{O_2} = \dfrac{n_{KMnO_4}}{2} = 0,05(mol)\\ n_P = \dfrac{24,8}{31} = 0,8(mol)\\ 4P + 5O_2 \xrightarrow{t^o} 2P_2O_5\\ \dfrac{n_P}{4} = 0,2 > \dfrac{n_{O_2}}{5} = 0,01 \to P\ dư\\ n_{P_2O_5} = \dfrac{2}{5}n_{O_2} = 0,02(mol)\\ m_{P_2O_5} = 0,02.142 = 2,84(gam)\)

a, \(2Mg+O_2\underrightarrow{^{t^o}}2MgO\)

\(n_{MgO}=\dfrac{2}{40}=0,05\left(mol\right)\)

\(n_{O_2}=\dfrac{1}{2}n_{MgO}=0,025\left(mol\right)\Rightarrow V_{O_2}=0,025.22,4=0,56\left(l\right)\)

b, Có lẽ đề cho oxi tác dụng với hidro chứ không phải oxit bạn nhỉ?

\(n_{H_2}=\dfrac{3,36}{22,4}=0,15\left(mol\right)\)

PT: \(2H_2+O_2\underrightarrow{^{t^o}}2H_2O\)

Xét tỉ lệ: \(\dfrac{0,15}{2}>\dfrac{0,025}{1}\), ta được H₂ dư.

THeo PT: \(n_{H_2O}=2n_{O_2}=0,05\left(mol\right)\Rightarrow m_{H_2O}=0,05.18=0,9\left(g\right)\)