\(3Fe + 2O_2 \xrightarrow{t^o} Fe_3O_4\\ Fe_3O_4 + 8HCl \to 2FeCl_3 + FeCl_2 + 4H_2O\\ FeCl_2 + 2KOH \to Fe(OH)_2 + 2KCl\\ 2Fe(OH)_2 + \dfrac{1}{2}O_2 + H_2O \to 2Fe(OH)_3\\ 2Fe(OH)_3 \xrightarrow{t^o} Fe_2O_3 + 3H_2O\)

\(Fe+O_2-->Fe_3O_4\\ Fe_3O_4+HCl-->FeCl_2+FeCl_3+H_2O\\ FeCl_2+NaOH-->Fe\left(OH\right)_2+NaCl\\ Fe\left(OH\right)_2+O_2+H_2O-->Fe\left(OH\right)_3\\ Fe\left(OH\right)_3-t^o->Fe_2O_3+H_2O\)

(1) 4 Na + O2 -to-> 2 Na2O

(2) Na2O + H2O -> 2 NaOH

(3) 3 NaOH + FeCl3 -> 3 NaCl + Fe(OH)3

(4) 2 Fe(OH)3 -to-> Fe2O3 + 3 H2O

(5) Fe2O3 + 3 CO -to-> 2 Fe + 3 CO2

(6) 2 Fe + 3 Cl2 -to-> 2 FeCl3

4Na + O2 -to-> 2Na2O 

Na2O + H2O => 2NaOH 

3NaOH + FeCl3 => 3NaCl + Fe(OH)3 

2Fe(OH)3 -to-> Fe2O3 + 3H2O 

Fe2O3 + 3H2 -to-> 2Fe + 3H2O 

Fe + 3/2Cl2 -to-> FeCl3 

a) 

(1) \(2Al+3FeCl_2\rightarrow2AlCl_3+3Fe\)

(2) \(2Fe+3Cl_2\underrightarrow{t^o}2FeCl_3\)

(3) \(FeCl_3+3NaOH\rightarrow Fe\left(OH\right)_3\downarrow+3NaCl\)

(4) \(2Fe\left(OH\right)_3\underrightarrow{t^o}Fe_2O_3+3H_2O\)

b) 

(1) \(2Cu+O_2\underrightarrow{t^o}2CuO\)

(2) \(CuO+2HCl\rightarrow CuCl_2+H_2O\)

(3) \(CuCl_2+2AgNO_3\rightarrow Cu\left(NO_3\right)_2+2AgCl\downarrow\)

(4) \(Cu\left(NO_3\right)_2+2NaOH\rightarrow Cu\left(OH\right)_2\downarrow+2NaNO_3\)

(5) \(Cu\left(OH\right)_2\underrightarrow{t^o}CuO+H_2O\)

(6) \(CuO+H_2\underrightarrow{t^o}Cu+H_2O\)

\(Fe_2O_3+3CO\underrightarrow{t^o}2Fe+3CO_2\)

\(Fe+2HCl->FeCl_2+H_2\uparrow\)

\(FeCl_2+AgNO_3->AgCl\downarrow+Fe\left(NO_3\right)_2\)

\(Fe\left(NO_3\right)_2+2NaOH->Fe\left(OH\right)_2\downarrow+2NaNO_3\)

\(Fe\left(OH\right)_2+H_2SO_4->FeSO_4+2H_2O\)

a, \(FeCl_3+3NaOH\rightarrow3NaCl+Fe\left(OH\right)_{3\downarrow}\)

\(2Fe\left(OH\right)_3\underrightarrow{t^o}Fe_2O_3+3H_2O\)

\(Fe_2O_3+3H_2\underrightarrow{t^o}2Fe+3H_2O\)

b, (1) \(Fe+2HCl\rightarrow FeCl_2+H_2\)

 \(FeCl_2+Zn\rightarrow ZnCl_2+Fe\)

\(Fe+H_2SO_{4\left(l\right)}\rightarrow FeSO_4+H_2\)

\(FeSO_4+2NaOH\rightarrow Na_2SO_4+Fe\left(OH\right)_{2\downarrow}\)

\(Fe\left(OH\right)_2\xrightarrow[khongcokhongkhi]{t^o}FeO+H_2O\)

\(FeO+H_2\underrightarrow{t^o}Fe+H_2O\)

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

\(Fe_3O_4+4H_2\underrightarrow{t^o}3Fe+4H_2O\)

\(2Fe+6H_2SO_{4\left(đ\right)}\underrightarrow{t^o}Fe_2\left(SO_4\right)_3+3SO_2+6H_2O\)

c, \(2FeS_2+\dfrac{11}{2}O_2\underrightarrow{t^o}Fe_2O_3+4SO_2\)

\(2SO_2+O_2⇌2SO_3\)

\(SO_3+H_2O\rightarrow H_2SO_4\)

\(CuO+H_2SO_4\rightarrow CuSO_4+H_2O\)

\(CuSO_4+2NaOH\rightarrow Cu\left(OH\right)_2+Na_2SO_4\)

\(Na_2SO_4+Ba\left(OH\right)_2\rightarrow2NaOH+BaSO_4\)

\(2NaOH+ZnO\rightarrow Na_2ZnO_2+H_2O\)

Bạn tham khảo nhé!

3Ba(OH)2 + 2FeCl3 → 3BaCl2 + 2Fe(OH)3,   Fe(OH)3 →Fe2O3+H2O,Fe2O3+3H2→2Fe+3H20

\(a,\left(1\right)Fe_2O_3+3H_2\rightarrow2Fe+3H_2O\left(1:3:2:3\right)\)

\(\left(2\right)Mg+2HCl\rightarrow MgCl_2+H_2\left(1:2:1:1\right)\\ \left(3\right)2FeCl_3+3Ca\left(OH\right)_2\rightarrow2Fe\left(OH\right)_3+3CaCl_2\left(2:3:2:3\right)\)

\(\left(4\right)K_2CO_3+2HCl\rightarrow2KCl+H_2O+CO_2\left(1:2:2:1:1\right)\)

\(b,PTHH:2Cu+O_2\underrightarrow{t^o}2CuO\\ Áp.dụng.ĐLBTKL,ta.có:\\ m_{Cu}+m_{O_2}=m_{CuO}\\ m_{O_2}=m_{CuO}-m_{Cu}=32-25,6=6,4\left(g\right)\)