1,C +2H2SO4->C02+2SO2 +2H2O 

2,P +5HNO3 ->H3P4O +5NO2 +H20 

3, 2PH3 +4O2 ->P2O5+3H2O 

4,4NH3 +5O2 ->4NO+6H2O 

5,SO2+Br2 +2H2O -> 2HBr +H2SO4 

6, 2KClO3+3C -> 2KCl +3CO2 

7, 3P +5HNO3 +2H2O -> 3H3PO4 +5NO  

8,2PH3 +4O2 ->P2O5+3H2O 

9, CH4 +2O2 -> CO2+ 2H2O

(1) \(K\overset{+7}{Mn}O_4+H\overset{-1}{Cl}\rightarrow KCl+\overset{+2}{Mn}Cl_2+\overset{0}{Cl_2}+H_2O\)

- Chất khử: HCl

Chất oxh: KMnO₄

- Sự oxh: \(2Cl^{-1}\rightarrow Cl_2^0+2e|\times5\)

Sự khử: \(Mn^{+7}+5e\rightarrow Mn^{+2}|\times2\)

\(\rightarrow2KMnO_4+16HCl\rightarrow2KCl+2MnCl_2+5Cl_2+8H_2O\)

(2) \(H\overset{+5}{N}O_3+\overset{0}{Cu}\rightarrow\overset{+2}{Cu}\left(NO_3\right)_2+\overset{+4}{N}O_2+H_2O\)

- Chất khử: Cu

Chất oxh: HNO₃

- Sự khử: \(N^{+5}+1e\rightarrow N^{+4}|\times2\)

Sự oxh: \(Cu^0\rightarrow Cu^{+2}+2e|\times1\)

\(\rightarrow4HNO_3+Cu\rightarrow Cu\left(NO_3\right)_2+2NO_2+2H_2O\)

(3) \(\overset{-3}{N}H_3+\overset{0}{O_2}\rightarrow\overset{+2}{N}\overset{-2}{O}+H_2O\)

- Chất khử: NH₃

 Chất oxh: O₂

- Sự khử: \(O_2^0+4e\rightarrow2O^{-2}|\times5\)

Sự oxh: \(N^{-3}\rightarrow N^{+2}+5e|\times4\)

\(\rightarrow4NH_3+5O_2\rightarrow4NO+6H_2O\)

1) 4K + O₂ → 2K₂O (4:1:2)

2) 2Al +3S→ Al₂S₃ (2:3:1)

3) 2SO₂ + O₂ → 2 SO₃ (2:1:2)

4)Fe₂O₃ + 6HNO₃ → 2Fe(NO₃)₃ + 3H₂O (1:6:2:3)

5)2K + 2H₂O → 2KOH + H₂ (2:2:2:1)

6) Al₂(SO₄)₃ + 6NaOH → 2Al(OH)₃ + 3Na₂SO₄ (1:6:2:3)

7) C₂H₆O + 3O₂ → 2CO₂ + 3H₂O (1:3:2:3)

8) 2FeCl₂ +3Cl₂ → 2FeCl₃  (2:3:2)

9) 4NO₂ + O₂ + 2H₂O → 4HNO₃ (4:1:2:4)

10) C_nH_2n + \(\dfrac{3n}{2}\)O₂ → nCO₂ + nH₂O (1:\(\dfrac{3n}{2}\):n:n)

\(1,4Na+O_2\rightarrow^{t^o}2Na_2O\\ 2,4P+5O_2\rightarrow^{t^o}2P_2O_5\\ 3,3Fe+2O_2\rightarrow^{t^o}Fe_3O_4\\ 4,2H_2+O_2\rightarrow^{t^o}2H_2O\\ 5,N_2+H_2⇌^{\left(t^o,xt,p\right)}NH_3\\ 6,P_2O_5+3H_2O\rightarrow2H_3PO_4\\ 7,N_2O_5+H_2O\rightarrow2HNO_3\\ 8,2Al+6HCl\rightarrow2AlCl_3+3H_2\\ 9,2Al+3H_2SO_4\rightarrow Al_2\left(SO_4\right)_3+3H_2\\ 10,2Cu+O_2\rightarrow^{t^o}2CuO\\ 11,CaO+2HNO_3\rightarrow Ca\left(NO_3\right)_2+H_2O\\ 12,Al\left(OH\right)_3+3HNO_3\rightarrow Al\left(NO_3\right)_3+3H_2O\\ 13,Zn+2HCl\rightarrow ZnCl_2+H_2\)

Bạn xem lại PT 1 và 3 nhé.

\(\overset{0}{Al}+H\overset{+5}{N}O_3\rightarrow\overset{+3}{Al}\left(NO_3\right)_3+\overset{0}{N_2}+H_2O\)

\(\overset{0}{Al\rightarrow}\overset{+3}{Al}+3e|\times10\)

\(2\overset{+5}{N}+10e\rightarrow\overset{0}{N_2}|\times3\)

⇒ 10Al + 36HNO₃ → 10Al(NO₃)₃ + 3N₂ + 18H₂O

\(\overset{^{+2y/x}}{Fe_x}O_y+H\overset{+5}{N}O_3\rightarrow\overset{+3}{Fe}\left(NO_3\right)_3+\overset{+4}{N}O_2+H_2O\)

\(\overset{^{+2y/x}}{Fe_x}\rightarrow x\overset{+3}{Fe}+\left(3x-2y\right)e|\times1\)

\(\overset{+5}{N}+e\rightarrow\overset{+4}{N}|\times\left(3x-2y\right)\)

⇒ Fe_xO_y + (6x-2y)HNO₃ → xFe(NO₃)₃ + (3x-2y)NO₂ + (3x-y)H₂O

Câu1.a)

1/Chất khử: NH₃

Chất oxh : N₂

2/Chất khử: Fe

Chất oxh : HNO₃

b) 1/ \(QToxh:2N^{-3}\rightarrow\overset{0}{N_2}+6e|\times2\\ QTkhử:\overset{0}{O_2}+4e\rightarrow2O^{2-}|\times3\\ \Rightarrow4NH_3+3O_2\rightarrow2N_2+6H_2O\)

2/ \(QToxh:\overset{0}{Fe}\rightarrow Fe^{+3}+3e|\times1\\ QTkhử:N^{+5}+1e\rightarrow N^{+4}|\times3\\ \Rightarrow Fe+6HNO_3\rightarrow Fe\left(NO_3\right)_3+3NO_2+3H_2O\)

Câu 3. \(Đặt:\left\{{}\begin{matrix}n_{Fe}=x\left(mol\right)\\n_{Mg}=y\left(mol\right)\end{matrix}\right.\\ Fe+2HCl\rightarrow FeCl_2+H_2\\ Mg+2HCl\rightarrow MgCl_2\\ n_{H_2}=0,6\left(mol\right)\\ Tacó:\left\{{}\begin{matrix}x+y=0,6\left(mol\right)\\56x+24y=20,8\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}x=0,2\\y=0,4\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}m_{FeCl_2}=0,2.127=25,4\\m_{MgCl_2}=0,4.95=38\left(g\right)\end{matrix}\right.\)