Ejercicios Resueltos de Balanceo

RESPUESTAS - TAREA # 3 MÉTODOS DE BALANCEO DE ECUACIONES QUÍMICAS Resuelva las siuie!"es euai$!es %$& el '("$)$ )e "a!"e$*

1.

a)

H2O + N2O5 → NHO3 H2O + N2O5 → 2NHO3

b)

HCl + Zn → ZnCl 2 + H2 2HCl + Zn → ZnCl2 + H2

c)

KClO 3 → KCl + O 2 2KClO3 → 2KCl + 3O2

d)

SO2 + O2 → SO3 2SO2 + O2 → 2SO3

"$ N  O

Rea#"iv 2 2 5

P&$)u#" 2 2 5

"$  Cl /!

Rea#"iv 2 2 1

P&$)u#" 2 2 1

"$ 0 Cl O

"$ S O

+.

Rea#"iv 2 $

"$ Cl  I

e) Cl2 + HI → I2 + HCl Cl2 + 2HI → I2 + 2HCl

Rea#"iv 2 2 $

P&$)u#" 2 2 $

P&$)u#" 2 $

Rea#"iv 2 2 2

P&$)u#" 2 2 2

Resuelva las siuie!"es euai$!es %$& el '("$)$ ale,&ai$ a. FeS2 + O2 → SO2 + Fe2O3

A

B

C

D

Fe: A = 2D

A=1x4= 4

S: 2A = C O: 2 = 2C + 3D

 = 11!4 x 4 = 11 C=2x4=" D=#x4= 2

1 = 2D D=#

2 = 2&2) + 3&1!2)  = 11!4

2&1) = C

"$ e S O

4 FeS2 + 11 O2 → " SO2 + 2

b.

Rea#"iv 4 " 22

P&$)u#" 4 " 1$+$

HCl + K%nO 4 → KCl + %nCl 2 + H2O + Cl2

A

B

C

D

E

H: A = 2' Cl: A = C + 2D + 2F K:  = C %n:  = D O: 4 = ' 1 = 2' '=#

4 = =

1!" = 1!" =



A = 1 x 1$ = 1$  = 1!" x 1$ = 2 C = 1!" x 1$ = 2 D = 1!" x 1$ = 2 ' = # x 1$ = " F = 1$!5 x 1$ = 5 2F = 1(1!"(2&1!") F = 5!1$

1$HCl 1$ HCl + 2K%nO4 → 2KCl + 2%nCl2 + "H2O + 5Cl2 "$

Rea#"iv

P&$)u#"

 Cl 0 M! O

1$ 1$ 2 2 "

1$ 2+4+1 2 2 "

c.

C* + HNO 3 → C*&NO3)2 + NO + H2

A

B

C

D

E

C*: A = C

A = 3!" x " = 3

H:  = 2' N:  = 2C + D

=1x"=" C = 3!" x " = 3

O: 3 = $C + D + '

1 = 2' '=#

D=x"= 2'=#x"= 4 3& = 2C + D) ' = 2D 3 B

1 = 2C + D

D=

= 6C + D +

C = 3!"

 E  − 3 B = −6C − 3 D = −2 D + E 

"$ Cu  N O

3 C* + " HNO3 = 3 C*&NO3)2 + 2 NO + 4 H2

d.

Rea#"iv 3 " " 24

P&$)u#" 3 " $+2 1"+2+4

K4Fe&CN)$ + K%nO4 + HCl → KCl + FeCl 3 + %nCl2 + CO2 + NO + H2O

A

B

C

D

E

K: 4A +  = D Fe: A = '

A=1x5= 5  = 43!5 x 5 = 43

C: $A = , N: $A = H

C = 1$4!5 x 5 = 1$4 D = $3!5 x 5 = $3

%n:  = F

'=1x5=5

O: 4 = 2, + H + I

F = 43!5 x 5 = 43

H: C = 2I Cl: C = D + 3' + 2F

, = $ x 5 = 3 H = $ x 5 = 3 I = "2!5 x 5 = "2

$&1) = H

C = 2I

$&1) = ,

C = D + 3' + 2F



2



I

2I = D + 3' + 2F " = 4, + 2H + 2I &d*-lca/0 la ec*acn del O) 2I = D+ 3' + 2F "  D  3'  2F = 4, + 2H &C0/0  = F e **6e F -07 ) "  D  3'  2 = 4, + 2H $ = 4, + 2H + D + 3' 4A +  = D &e 7ea) 5  4A = 4, + 2H + 3' 5  4&1) = 4&$) + 2&$) + 3&1)  = 24+12+3+4!5  = 43!5

4A +  = D 4&1) + 43!5 = D = $3!5

C = D + 3' + 2F C = $3!5 + 3&1) + C = 1$4!5

C = 2I I = "2!5

5K4Fe&CN)$ + 43K%nO4 + 1$4HCl = $3KCl + 5FeCl3 + 43%nCl2 + 3CO2 + 3NO + "2H2O

e. 8bS + HNO3 → 8b&NO3)2 + NO + S + H 2O  A  C D ' F 8b: A = C A=1x3= 3 S: A = '  = "!3 x 3 = " H:  = 2F

C=1x3=3

N:  = 2C + D

D = 2!3 x 3 = 2

O: 3 = $C + D + F

 = 2C + D

'=1x3=3 F = 4!3 x 3 = 4  = 2F D =   2C

( = (2F = 2C  2F + D 3 = $C + D + F = (2C + 2F

 = 2&4!3)  = "!3

D = "!3 (2 D = 2!3

(3 = ($F = 4C  3F F = 4!3 38bS + "HNO3 = 38b&NO3)2 + 2NO + 3S + 4H2O

3.

"$ P, S  N O

Rea#"iv 3 3 " " 24

Resuelva las siuie!"es euai$!es %$& el '("$)$ )el !'e&$ )e la vale!ia $ !'e&$ )e $4i)ai5!. a) +9 (1 +2  K%nO4 + AlI3 + H2SO4 = %nSO4 + K2SO4 + Al2&SO4)3 + I2 + H2O ed=5

Ox=3

;*e<0 e d*-lcan l0 c0ecene -07  e7 /-a7e -a7a acla7 la <*alacn: ed=5x2=1 Ox=3x2=$ $K%nO4 + 1 AlI3 + 24H2SO4 = $%nSO4 + 3K2SO4 + 5Al2&SO4)3 + 15I2 + 24H2O b) +1+5(2 +1(2 +2(2  +1(2 HNO3 + H2S = NO + S + H2 ed = 3

Ox = 2

2HNO3 + 3H2S = 2NO + 3S + 4H2 c) +3(1



+9

+$

(1

C7I3 + NaOH + Cl2 = NaIO4 + Na2C7O4 + NaCl + H2O Ox=3x1= 3 ed=1x2=2 Ox="x3=24 29 2C7I3 + $4NaOH + 29Cl2 = $NaIO4 + 2Na2C7O4 + 54NaCl + 32H2O d) +2

+1

+3

+3(1

FeSO4 + H7O + H2SO4 = Fe2&SO4)3 + Fe73 + H2O ed=1x2=2 ed=1 Ox=2x3=$ Ox=5 12FeSO4 + $H7O + 3H2SO4 = 5Fe2&SO4)3 + 2Fe73 + $H2O e) 

(1

+5

NaOH + I2 = NaI + NaIO3 + H2 Ox=1

ed=5

$NaOH + 3I2 = 5NaI + NaIO3 + 3H2 6.

P&$)u#" 3 3 " $+2 1"+2+4

Resuelva las siuie!"es euai$!es %$& el '("$)$ )el i$! ele"&5! a. -1

73

7+

8

KI + FeCl3 = FeCl2 + KCl + I 2

-1

8

73

7+

2I = I2

Fe = Fe

Incl*n de elec70ne: 2I  2e = I2

Fe + 1e = Fe

Ine7ca/b0 de c0ecene 6 an*lacn de elec70ne: 2I  2e = I 2 2Fe + 2e = 2Fe S*/a de ec*ac0ne nca: 2I + 2Fe = I2 + 2Fe

Euai5! iuala)a*

2KI + 2FeCl3 = 2FeCl2 + 2KCl + I2

,. -3

7+

8

8

NH3 + C*O = H 2 + N2 + C* 'c*ac0ne nca <*alada: (3  +2  2N = N2 C* = C* Incl*n de elec70ne: 2N  $e = N2 C* + 2e = C* Ine7ca/b0 de c0ecene 6 an*lacn de elec70ne: 1&2N  $e = N 2) 3&C* + 2e = C*) S*/a de ec*ac0ne nca: 2N + 3C* = N2 + 3C*

Euai5! iuala)a*

2NH3 + 3C*O = 3H 2 + N2 + 3C*

. 8

7+

73

8

 Al + C*SO4 = Al2&SO4)3 + C* 'c*ac0ne nca <*alada:  +3 +2   Al = Al C* = C* Incl*n de elec70ne:  Al  3e = Al C* + 2e = C* Ine7ca/b0 de c0ecene 6 an*lacn de elec70ne: 2&Al  3e = Al) 3&C* + 2e = C*) S*/a de ec*ac0ne nca: 2Al + 3C* = 2Al + 3C*

Euai5! iuala)a* 2 Al + 3C*SO4 = Al2&SO4)3 + 3C* d.

79

-1

7+

8

K%nO4 + KI + H 2SO4 = K2SO4 + %nSO4 + I2 + H2O 'c*ac0ne nca <*alada: +9

+2

%n = %n

(1  I = I2

Incl*n de elec70ne: %n + 5e = %n

2I ( 2e = I2

Ine7ca/b0 de c0ecene 6 an*lacn de elec70ne: 2&%n + 5e = %n) 5&2I ( 2e = I) S*/a de ec*ac0ne nca: 2%n + 1I = 2%n + 5I

Euai5! iuala)a* 2K%nO4 + 1KI + "H2SO4 = $K2SO4 + 2%nSO4 + 5I2 + "H2O

e.

7:

-+

73

8

K2C7 2O9 + H2S + H2SO4 = K2SO4 + C7 2&SO4)3 + S + H2O 'c*ac0ne nca <*alada: +$ +3 C7 = C7

(2  S=S

Incl*n de elec70ne: C7 + 3e = C7 S ( 2e = S Ine7ca/b0 de c0ecene 6 an*lacn de elec70ne: 2&C7 + 3e = C7) 3&S ( 2e = S) S*/a de ec*ac0ne nca: 2C7 + 3S = 2C7 + 3S

Euai5! iuala)a* K2C7 2O9 + 3H2S + 4H2SO4 = K2SO4 + C7 2&SO4)3 + 3S + 9H 2O ;.

Resuelva las siuie!"es euai$!es %$& l$s '("$)$s* ale,&ai$< !'e&$ )e vale!ia = )el i$! ele"&5!* a.

 Algebraico:

HNO3 + H2S = NO + S + H2O

A

B

C

D

H: A + 2 = 2'

E A= 1x 2=2

N: A = C

 = 3!2 x 2 = 3

O: 3A = C + '

C=1x2=2

S:  = D

D = 3!2 x 2 = 3 '=2x2=4

3A = C + '

A + 2 = 2'

' = 3&1)  1 '=2 3!2

2 = 2' ( A  = &2&2)  1)!2 =

Ecuación balanceada: 2HNO3 + 3H2S = +NO + 3S + 6H2O Número de valencia: +5

(2

+2



HNO3 + H2S = NO + S + H2O ed = 3

Ox=2

Ecuación balanceada: 2HNO3 + 3H2S = +NO + 3S + 6H2O Ión electrón: +5 (2 +2  HNO3 + H2S = NO + S + H2O +5 +2

(2 

N=N S=S Incl*n de elec70ne: N + 3e = N

S ( 2e = S

Ine7ca/b0 de c0ecene 6 an*lacn de elec70ne: 2&N + 3e = N) 3&S ( 2e = S) S*/a de ec*ac0ne nca: 2N + 3S = 2N + 3S Ecuación balanceada: 2HNO3 + 3H2S = +NO + 3S + 6H2O

b.

 Algebraico:

I2 + HNO3 = HI4 + NO + H2O  A  C D ' I: 2A = C

A = 3!14 x 14 = 3

H:  = C + 2' N:  = D

 = 1 x 14 = 14 C = 3!9 x 14 = $

O: 3 = 4C + D + '

D = 1 x 14 = 14 ' = 2!9 x 14 = 4

3 = 4C + D + ' 3   = 4C + ' 2 = 4C + '

C =   2' C = 1  2&2!9) C = 3!9

2A = C 2A = 3!9 A = 3!14

2&1) = 4&  2') + ' 2 = 4  "' + ' ' = 4&1)  2 ! 9 = 2!9 Ecuación igualada:

3I2 + 14HNO3 = $HI4 + 14NO + 4H2O Número de valencia:



+1+5(2

+1+9(2 +2(2

+1(2

I2 + HNO3 = HI4 + NO + H2O S*b>ndce: 2+1 = 3

1+1 = 2

I: Ox=9x2 = 14 &e /*l-lca -07 el *b>ndce) N: ed=3x1=3 Ecuación igualada: 3I2 + 14HNO3 = $HI4 + 14NO + 4H2O Ión electrón: 

+5

+9

+2

I2 + HNO3 = HI4 + NO + H2O 

+9

+5 +2

I2 = 2I

N=N

Incl*n de elec70ne: I2 ( 14e = 2I N + 3e = N Ine7ca/b0 de c0ecene 6 an*lacn de elec70ne: 3&I2 ( 14e = 2I) 14&N + 3e = N) S*/a de ec*ac0ne nca: 3I2 + 14N = $I + 14N Ecuación igualada: 3I2 + 14HNO3 = $HI4 + 14NO + 4H2O c.

 Algebraico:

C* + HNO3 = C*&NO3)2 + NO + H2O  A  C D ' C*: A = C H:  = 2'

A= 1x 3=3  = "!3 x 3 = "

N:  = 2C + D

C=1x3=3

O: 3 = $C + D + '

3 = $C + D + ' 2C  = 2C + D 2

D = 2!3 x 3 = 2 ' = 4!3 x 3 = 4  = 2' D=  = 2&4!3) D = "!3 

2 = 4C + '

 = "!3

D = 2!3

2&2') = 4 + ' 4'  ' = 4 ' = 4!3 Ecuación igualada:

3C* + "HNO3 = 3C*&NO3)2 + 2NO + 4H2O

Número de valencia:

8

7;

7+

7+

C* + HNO3 = C*&NO3)2 + NO + H2O ed=2

Ox=3

;a <*alacn e ?ace a -a77 del e<*nd0 /e/b70 -07 la 7e-ecn de l0 @0/0 de n7
3C* + "HNO3 = 3C*&NO3)2 + 2NO + 4H2O Ión electrón:

8

7;

7+

7+

C* + HNO3 = C*&NO3)2 + NO + H2O

8

7+

C* = C*

7; 7+ N=N

Incl*n de elec70ne: C* ( 2e = C* N + 3e = N Ine7ca/b0 de c0ecene 6 an*lacn de elec70ne: 3&C* ( 2e = C*) 2&N + 3e = N) S*/a de ec*ac0ne nca: 3C* + 2N = 3C* + 2N Ecuación igualada: 3C* + "HNO3 = 3C*&NO3)2 + 2NO + 4H2O