Ppt redox nivel pre

1. BALANCEO DE
REACCIONES
Rubén Cueva García
FÍSICA QUÍMICA BIOLOGÍA

2. Na2Cr2O7 + HBr → NaBr + CrBr3 + Br2 + H2O

3. a Na2Cr2O7 + b HBr → c NaBr + d CrBr3 + e Br2 + f H2O

4. a Na2Cr2O7 + b HBr → c NaBr + d CrBr3 + e Br2 + f H2O
a= 1

5. 1 Na2Cr2O7 + b HBr → 2 NaBr + d CrBr3 + e Br2 + f H2O
a= 1

6. 1 Na2Cr2O7 + b HBr → 2 NaBr + 2 CrBr3 + e Br2 + f H2O
a= 1

7. 1 Na2Cr2O7 + b HBr → 2 NaBr + 2 CrBr3 + e Br2 + 7 H2O
a= 1

8. 1 Na2Cr2O7 + 14 HBr → 2 NaBr + 2 CrBr3 + e Br2 + 7 H2O
a= 1

9. 1 Na2Cr2O7 + 14 HBr → 2 NaBr + 2 CrBr3 + e Br2 + 7 H2O
a= 1

10. 1 Na2Cr2O7 + 14 HBr → 2 NaBr + 2 CrBr3 + e Br2 + 7 H2O
2 + 6 + 6

11. 1 Na2Cr2O7 + 14 HBr → 2 NaBr + 2 CrBr3 + 3 Br2 + 7 H2O
2 + 6 + 6

12. 1 Na2Cr2O7 + 14 HBr → 2 NaBr + 2 CrBr3 + 3 Br2 + 7 H2O

13. KMnO4 + HCl → KCl + MnCl2 + Cl2 + H2O

14. a KMnO4 + b HCl → c KCl + d MnCl2 + e Cl2 + f H2O

15. a KMnO4 + b HCl → c KCl + d MnCl2 + e Cl2 + f H2O
a= 1

16. 1 KMnO4 + b HCl → 1 KCl + d MnCl2 + e Cl2 + f H2O
a= 1

17. 1 KMnO4 + b HCl → 1 KCl + 1 MnCl2 + e Cl2 + f H2O
a= 1

18. 1 KMnO4 + b HCl → 1 KCl + 1 MnCl2 + e Cl2 + 4 H2O
a= 1

19. 1 KMnO4 + b HCl → 1 KCl + 1 MnCl2 + e Cl2 + 4 H2O
a= 1

20. 1 KMnO4 + 8 HCl → 1 KCl + 1 MnCl2 + e Cl2 + 4 H2O
a= 1

21. 1 KMnO4 + 8 HCl → 1 KCl + 1 MnCl2 + e Cl2 + 4 H2O
a= 1

22. 1 KMnO4 + 8 HCl → 1 KCl + 1 MnCl2 + e Cl2 + 4 H2O
1 + 2 + 5

23. 1 KMnO4 + 8 HCl → 1 KCl + 1 MnCl2 + 5/2 Cl2 + 4 H2O
1 + 2 + 5

24. 1 KMnO4 + 8 HCl → 1 KCl + 1 MnCl2 + 5/2 Cl2 + 4 H2O
2 KMnO4 + 16 HCl → 2 KCl + 2 MnCl2 + 5 Cl2 + 8 H2O

26. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O

27. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f

28. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f
Mn: a = e
O: 4 a + 4 b + 4 c = 12 d + 4 e + 4f + g

29. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f
Mn: a = e
O: 4 a + 4 b + 4 c = 12 d + 4 e + 4f + g
H: 2 b = 2 g
S: b + c = 3 d + e + f

30. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f
Mn: a = e
O: 4 a + 4 b + 4 c = 12 d + 4 e + 4f + g
H: 2 b = 2 g
S: b + c = 3 d + e + f
a= 1

31. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f
Mn: a = e
O: 4 a + 4 b + 4 c = 12 d + 4 e + 4f + g
H: 2 b = 2 g
S: b + c = 3 d + e + f
a= 1
f = 1/2
e = 1

32. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f
Mn: a = e
O: 4 a + 4 b + 4 c = 12 d + 4 e + 4f + g
H: 2 b = 2 g
S: b + c = 3 d + e + f
a= 1
f = 1/2
e = 1
b + c = 3 d + 1 + 1/2
Fe: c = 2 d

33. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f
Mn: a = e
O: 4 a + 4 b + 4 c = 12 d + 4 e + 4f + g
H: 2 b = 2 g
S: b + c = 3 d + e + f
a= 1
f = 1/2
e = 1
b + 2d = 3 d + 1 + 1/2
Fe: c = 2 d

34. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f
Mn: a = e
O: 4 a + 4 b + 4 c = 12 d + 4 e + 4f + g
H: 2 b = 2 g
S: b + c = 3 d + e + f
a= 1
f = 1/2
e = 1
b = d + 3/2
Fe: c = 2 d
b + 2d = 3 d + 1 + 1/2

35. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f
Mn: a = e
O: 4 a + 4 b + 4 c = 12 d + 4 e + 4f + g
H: 2 b = 2 g
S: b + c = 3 d + e + f
a= 1
f = 1/2
e = 1
b = d + 3/2
Fe: c = 2 d
4(1) + 4b + 4c = 12 d + 4(1) + 4 (1/2) + g
4b + 4c = 12d + 2 + g

36. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f
Mn: a = e
O: 4 a + 4 b + 4 c = 12 d + 4 e + 4f + g
H: 2 b = 2 g
S: b + c = 3 d + e + f
a= 1
f = 1/2
e = 1
b = d + 3/2
Fe: c = 2 d
4b + 4c = 12d + 2 + g
4b + 4 (2 d) = 12 d + 2 + b
3 b = 4 d + 2

37. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f
Mn: a = e
O: 4 a + 4 b + 4 c = 12 d + 4 e + 4f + g
H: 2 b = 2 g
S: b + c = 3 d + e + f
a= 1
f = 1/2
e = 1
b = d + 3/2
Fe: c = 2 d
3 b = 4 d + 2
3 (d + 3/2) = 4 d + 2
5/2 = d
b = 4
3 b = 4 (5/2) + 2

38. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f
Mn: a = e
O: 4 a + 4 b + 4 c = 12 d + 4 e + 4f + g
H: 2 b = 2 g
S: b + c = 3 d + e + f
a= 1
f = 1/2
e = 1
Fe: c = 2 d
5/2 = d
b = 4
c = 5
g = 4

39. a KMnO4 + b H2SO4 + c FeSO4 → d Fe2(SO4)3 + e MnSO4 + f K2SO4 + gH2O
K: a = 2f
Mn: a = e
O: 4 a + 4 b + 4 c = 12 d + 4 e + 4f + g
H: 2 b = 2 g
S: b + c = 3 d + e + f
a= 1
f = 1/2
e = 1
Fe: c = 2 d
5/2 = d b = 4
c = 5 g = 4
a = 2 ; b = 8 ; c = 10 ; d = 5 ; e = 2 ; f = 1; g = 8
Todos x 2

41. Método redox

42. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O

43. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
-2 -2 -2 -2 -2 -2 -2
Oxígeno O : -2

44. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
-2 +1 -2 -2 -2 -2 -2 +1 -2
Hidrógeno H: +1

45. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
-2 +1 -2 -2 -2 -2 -2 +1 -2

46. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
+1 -2 +1 -2 -2 -2 -2 +1 -2 +1 -2
Metales
Li Na K Ag +1
Be Mg Ca Sr Ba Ra Zn +2
Al +3

47. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
+1 -2 +1 -2 -2 -2 -2 +1 -2 +1 -2
+1 -8 +2 -8 -8 +6 -24 -8 +2 -8 +2 -2
Total de cargas = 0
Electroneutralidad

48. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
+1 -2 +1 -2 -2 +3 -2 +2 -2 +1 -2 +1 -2
+1 -8 +2 -8 -8 +6 -24 +2 -8 +2 -8 +2 -2
Hierro Fe 2 3
Manganeso (metal) 2 3

49. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
+1 7 -2 +1 6 -2 2 6 -2 +3 6 -2 +2 6 -2 +1 6 -2 +1 -2
+1 7 -8 +2 6 -8 2 6 -8 +6 18-24 +2 6 -8 +2 6-8 +2 -2

50. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
+1 7 -2 +1 6 -2 2 6 -2 +3 6 -2 +2 6 -2 +1 6 -2 +1 -2
+1 7 -8 +2 6 -8 2 6 -8 +6 18-24 +2 6 -8 +2 6-8 +2 -2
Mn +7 Mn +2

51. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
+1 7 -2 +1 6 -2 2 6 -2 +3 6 -2 +2 6 -2 +1 6 -2 +1 -2
+1 7 -8 +2 6 -8 2 6 -8 +6 18-24 +2 6 -8 +2 6-8 +2 -2
Mn +7 Mn +2
Fe+2 Fe +3
2

52. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
+1 7 -2 +1 6 -2 2 6 -2 +3 6 -2 +2 6 -2 +1 6 -2 +1 -2
+1 7 -8 +2 6 -8 2 6 -8 +6 18-24 +2 6 -8 +2 6-8 +2 -2
Mn +7 +5 e- Mn +2
2 Fe+2 -2 e- Fe +3
2

53. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
+1 7 -2 +1 6 -2 2 6 -2 +3 6 -2 +2 6 -2 +1 6 -2 +1 -2
+1 7 -8 +2 6 -8 2 6 -8 +6 18-24 +2 6 -8 +2 6-8 +2 -2
Mn +7 +5 e- Mn +2
2 Fe+2 -2 e- Fe +3
2

54. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
+1 7 -2 +1 6 -2 2 6 -2 +3 6 -2 +2 6 -2 +1 6 -2 +1 -2
+1 7 -8 +2 6 -8 2 6 -8 +6 18-24 +2 6 -8 +2 6-8 +2 -2
Mn +7 +5 e- Mn +2
2 Fe+2 -2 e- Fe +3
2
x 2
x 5

55. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
2 Mn +7 +10 e- 2 Mn +2
10 Fe+2 - 10 e- 5 Fe +3
2

56. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
2 Mn +7 + 10 Fe +2 5 Fe+3
2 + 2 Mn +2

57. 2 KMnO4 + _H2SO4 + 10FeSO4 → 5 Fe2(SO4)3 + 2 MnSO4 + _K2SO4 + _H2O
2 KMnO4 + _H2SO4 + 10FeSO4 → 5 Fe2(SO4)3 + 2 MnSO4 + 1K2SO4 + _H2O

58. 2 KMnO4 + _H2SO4 + 10FeSO4 → 5 Fe2(SO4)3 + 2 MnSO4 + _K2SO4 + _H2O
2 KMnO4 + _H2SO4 + 10FeSO4 → 5 Fe2(SO4)3 + 2 MnSO4 + 1K2SO4 + _H2O
2 KMnO4 + 8H2SO4 + 10FeSO4 → 5 Fe2(SO4)3 + 2 MnSO4 + K2SO4 + _H2O

59. 2 KMnO4 + _H2SO4 + 10FeSO4 → 5 Fe2(SO4)3 + 2 MnSO4 + _K2SO4 + _H2O
2 KMnO4 + _H2SO4 + 10FeSO4 → 5 Fe2(SO4)3 + 2 MnSO4 + 1K2SO4 + _H2O
2 KMnO4 + 8H2SO4 + 10FeSO4 → 5 Fe2(SO4)3 + 2 MnSO4 + K2SO4 + _H2O
2 KMnO4 + 8H2SO4 + 10FeSO4 → 5 Fe2(SO4)3 + 2 MnSO4 + K2SO4 + 8 H2O

60. Redox ion-electrón

61. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O

62. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
(K+) (MnO4
-) 2(H+) (SO4
-2) (Fe+2)(SO4
-2) (Fe+3)2 Mn+2 K+1
2 H2O
3 (SO4
-2) (SO4
-2) (SO4
-2)

63. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
(K+) (MnO4
-) 2(H+) (SO4
-2) (Fe+2)(SO4
-2) (Fe+3)2 Mn+2 K+1
2 H2O
3 (SO4
-2) (SO4
-2) (SO4
-2)
(MnO4
-) Mn+2
Fe +2 (Fe+3)2

64. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
(K+) (MnO4
-) 2(H+) (SO4
-2) (Fe+2)(SO4
-2) (Fe+3)2 Mn+2 K+1
2 H2O
3 (SO4
-2) (SO4
-2) (SO4
-2)
(MnO4
-) Mn+2
2 Fe +2 (Fe+3)2

65. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
(K+) (MnO4
-) 2(H+) (SO4
-2) (Fe+2)(SO4
-2) (Fe+3)2 Mn+2 K+1
2 H2O
3 (SO4
-2) (SO4
-2) (SO4
-2)
(MnO4
-) Mn+2 + 4 _ O
2 Fe +2 (Fe+3)2

66. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
(K+) (MnO4
-) 2(H+) (SO4
-2) (Fe+2)(SO4
-2) (Fe+3)2 Mn+2 K+1
2 H2O
3 (SO4
-2) (SO4
-2) (SO4
-2)
(MnO4
-) Mn+2 + 4 H2 O
2 Fe +2 (Fe+3)2

67. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
(K+) (MnO4
-) 2(H+) (SO4
-2) (Fe+2)(SO4
-2) (Fe+3)2 Mn+2 K+1
2 H2O
3 (SO4
-2) (SO4
-2) (SO4
-2)
(MnO4
-) + 8 H+ Mn+2 + 4 H2 O
2 Fe +2 (Fe+3)2

68. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
(MnO4
-) + 8 H+ Mn+2 + 4 H2 O
2 Fe +2 - 2 e- (Fe+3)2

69. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
(MnO4
-) + 8 H+ + 5 e - Mn+2 + 4 H2 O
2 Fe +2 - 2 e- (Fe+3)2

70. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
(MnO4
-) + 8 H+ + 5 e - Mn+2 + 4 H2 O
2 Fe +2 - 2 e- (Fe+3)2
x 2
x 5

71. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
2(MnO4
-) + 16 H+ + 10 e - 2 Mn+2 + 8 H2 O
10 Fe +2 - 10 e- 5 (Fe+3)2

72. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
2(MnO4
-) + 16 H+ + 10 e - 2 Mn+2 + 8 H2 O
10 Fe +2 - 10 e- 5 (Fe+3)2
2 KMnO4 + 8H2SO4 + 10FeSO4 → 5Fe2(SO4)3 + 2MnSO4 + K2SO4 + 8H2O

73. KMnO4 + H2SO4 + FeSO4 → Fe2(SO4)3 + MnSO4 + K2SO4 + H2O
2 KMnO4 + 8H2SO4 + 10FeSO4 → 5Fe2(SO4)3 + 2MnSO4 + K2SO4 + 8H2O

75. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O

76. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 d

77. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 d
O: 7 a + 4 b = 12 d + 4f + g
H: 2 b = 2 g

78. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 d
O: 7 a + 4 b = 12 d + 4f + g
H: 2 b = 2 g
S: b = 3 d + f
Br: c = 2 e

79. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 d
O: 7 a + 4 b = 12 d + 4f + g
H: 2 b = 2 g
S: b = 3 d + f
Br: c = 2 e
a= 1

80. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 e
O: 7 a + 4 b = 12 d + 4f + g
H: 2 b = 2 g
S: b = 3 d + f
Br: c = 2 e
a= 1
d = 1

81. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 d
O: 7 a + 4 b = 12 d + 4f + g
H: 2 b = 2 g
S: b = 3 d + f
Br: c = 2 e
a= 1
d = 1
b = 3(1) + f
2 + c = 2 f

82. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 d
O: 7 a + 4 b = 12 d + 4f + g
H: 2 b = 2 g
S: b = 3 d + f
Br: c = 2 e
a= 1
d = 1 b = 3 + f
2 + c = 2 f

83. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 d
O: 7 a + 4 b = 12 d + 4f + g
H: 2 b = 2 g
S: b = 3 d + f
Br: c = 2 e
a= 1
d = 1 b = 3 + f
2 + c = 2 f
7 a + 4 b = 12 d + 4f + g
7 (1) + 4 b = 12 (1) + 4f + g

84. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 d
O: 7 a + 4 b = 12 d + 4 f + g
H: 2 b = 2 g
S: b = 3 d + f
Br: c = 2 e
a= 1
d = 1 b = 3 + f
2 + c = 2 f
7 a + 4 b = 12 d + 4 f + g
4 (3 + f) = 5 + 4 f + b
4 (3 + f) = 5 + 4 f + (3 + f)

85. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 d
O: 7 a + 4 b = 12 d + 4 f + g
H: 2 b = 2 g
S: b = 3 d + f
Br: c = 2 e
a= 1
d = 1 b = 3 + f
2 + c = 2 f
4 (3 + f) = 5 + 4 f + (3 + f)
12 + 4 f = 8 + 5 f
12 – 8 = 5 f – 4 f
4 = f

86. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 d
O: 7 a + 4 b = 12 d + 4 f + g
H: 2 b = 2 g
S: b = 3 d + f
Br: c = 2 e
a= 1
d = 1 b = 3 + f
2 + c = 2 f
4 (3 + f) = 5 + 4 f + (3 + f)
12 – 8 = 5 f – 4 f
4 = f b = 7 = g

87. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 d
O: 7 a + 4 b = 12 d + 4 f + g
H: 2 b = 2 g
S: b = 3 d + f
Br: c = 2 e
a= 1
d = 1 b = 3 + f
2 + c = 2 f
4 = f
b = 7 = g
2 + c = 2 f
c = 6
2 + c = 2 (4)
e = 3

88. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
Na: 2 a + c = 2 f
Cr: 2 a = 2 d
O: 7 a + 4 b = 12 d + 4 f + g
H: 2 b = 2 g
S: b = 3 d + f
Br: c = 2 e
a= 1
d = 1
f = 4
g = 7
b = 7
c = 6
e = 3

89. Método redox

90. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O

91. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O
Oxígeno O : -2
-2 -2 -2 -2 -2

92. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O
-2 +1 -2 -2 -2 +1 -2
Hidrógeno H: +1

93. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O
-2 +1 -2 -2 -2 +1 -2
Metales
Li Na K Ag +1
Be Mg Ca Sr Ba Ra Zn +2
Al +3

94. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O
+1 -2 +1 -2 +1 -2 +1 -2 +1 -2
Metales
Li Na K Ag +1
Be Mg Ca Sr Ba Ra Zn +2
Al +3

95. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O
+1 -2 +1 -2 +1 -2 +1 -2 +1 -2
Total de cargas = 0
Electroneutralidad
+2 -14 +2 -8 +1 +6 -24 0 +2 -8 +2 -2

96. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O
+1 -2 +1 -2 +1 -2 +1 -2 +1 -2
+2 12 -14 +2 6 -8 +1 -1 +6 18 -24 0 +2 6 -8 +2 -2
Cromo 2 3 6
Azufre 2 4 6

97. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O
+1 6 -2 +1 6 -2 +1 -1 3 6 -2 0 +1 6 -2 +1 -2
+2 12 -14 +2 6 -8 +1 -1 +6 18 -24 0 +2 6 -8 +2 -2

98. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O
+1 6 -2 +1 6 -2 +1 -1 3 6 -2 0 +1 6 -2 +1 -2
+2 12 -14 +2 6 -8 +1 -1 +6 18 -24 0 +2 6 -8 +2 -2
Cr2
+6 Cr2
+3

99. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O
+1 6 -2 +1 6 -2 +1 -1 3 6 -2 0 +1 6 -2 +1 -2
+2 12 -14 +2 6 -8 +1 -1 +6 18 -24 0 +2 6 -8 +2 -2
Cr2
+6 Cr2
+3
Br-1 Br2
0

100. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
+1 6 -2 +1 6 -2 +1 -1 3 6 -2 0 +1 6 -2 +1 -2
+2 12 -14 +2 6 -8 +1 -1 +6 18 -24 0 +2 6 -8 +2 -2
Cr2
+6 + 6 e- Cr2
+3
2 Br-1 – 2 e- Br2
0

101. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
+1 6 -2 +1 6 -2 +1 -1 3 6 -2 0 +1 6 -2 +1 -2
Cr2
+6 + 6 e- Cr2
+3
2 Br-1 – 2 e- Br2
0
x 3

102. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
+1 6 -2 +1 6 -2 +1 -1 3 6 -2 0 +1 6 -2 +1 -2
Cr2
+6 + 6 e- Cr2
+3
2 Br-1 – 2 e- Br2
0
x 3
x 1

103. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
1 Cr2
+6 + 6 e- 1 Cr2
+3
6 Br-1 – 6 e- 3 Br2
0

104. a Na2Cr2O7 + b H2SO4 + c NaBr → d Cr2(SO4)3 + e Br2 + f Na2SO4 + gH2O
1 Cr2
+6 + 6 Br-1 1 Cr2
+3
+ 3 Br2
0

105. 1 Na2Cr2O7 + _ H2SO4 + 6 NaBr → 1 Cr2(SO4)3 + 3 Br2 + _ Na2SO4 + _H2O
1 Cr2
+6 + 6 Br-1 1 Cr2
+3
+ 3 Br2
0

106. 1 Na2Cr2O7 + _ H2SO4 + 6 NaBr → 1 Cr2(SO4)3 + 3 Br2 + _ Na2SO4 + _H2O
1 Na2Cr2O7 + _ H2SO4 + 6 NaBr → 1 Cr2(SO4)3 + 3 Br2 + 4 Na2SO4 + _H2O

107. 1 Na2Cr2O7 + _ H2SO4 + 6 NaBr → 1 Cr2(SO4)3 + 3 Br2 + _ Na2SO4 + _H2O
1 Na2Cr2O7 + _ H2SO4 + 6 NaBr → 1 Cr2(SO4)3 + 3 Br2 + 4 Na2SO4 + _H2O
1 Na2Cr2O7 + 7 H2SO4 + 6 NaBr → 1 Cr2(SO4)3 + 3 Br2 + 4 Na2SO4 + _H2O

108. 1 Na2Cr2O7 + _ H2SO4 + 6 NaBr → 1 Cr2(SO4)3 + 3 Br2 + _ Na2SO4 + _H2O
1 Na2Cr2O7 + _ H2SO4 + 6 NaBr → 1 Cr2(SO4)3 + 3 Br2 + 4 Na2SO4 + _H2O
1 Na2Cr2O7 + 7 H2SO4 + 6 NaBr → 1 Cr2(SO4)3 + 3 Br2 + 4 Na2SO4 + _H2O
1 Na2Cr2O7 + 7 H2SO4 + 6 NaBr → 1 Cr2(SO4)3 + 3 Br2 + 4 Na2SO4 + 7H2O

109. Redox ion-electrón

110. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O

111. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O
2(Na+) (Cr2O7
-2) 2(H+) (SO4
-2) (Na+1)(Br-1)
2(Cr+3) Br0
2 2 Na+1 H2O
3 (SO4
-2) (SO4
-2)

112. Na2Cr2O7 + H2SO4 + NaBr → Cr2(SO4)3 + Br2 + Na2SO4 + H2O
Br -1 Br2
0
(Cr2O7) -2 Cr2
+3

113. (Cr2O7) = Cr2
+3 + 7 H2 O
2 Br – 1 - 2 e- Br2
0

114. (Cr2O7) = + 14 H+1 Cr2
+3 + 7 H2 O
2 Br – 1 Br2
0

115. (Cr2O7) = + 14 H+1 + 6 e - Cr2
+3 + 7 H2 O
2 Br – 1 - 2 e- Br2
0
x 1
x 3

116. 1 Na2Cr2O7 + 7 H2SO4 + 6 NaBr → 1 Cr2(SO4)3 + 3 Br2 + _ Na2SO4 + 7H2O
1 Na2Cr2O7 + 7 H2SO4 + 6 NaBr → 1 Cr2(SO4)3 + 3 Br2 + 4 Na2SO4 + 7H2O