1. Drill:
List five factors & explain how each affect reaction rates

2. Drill: Solve Rate Law A + B C + D fast 4 C + A 2G fast 2 K 4D + B fast
G + K Q + 2 W fast
Q + W Prod. slow

3. Chemical Equilibria

4. Equilibrium
The point at which the rate of a forward reaction = the rate of its reverse reaction

5. Equilibrium
The concentration of all reactants & products become constant at equilibrium

6. Equilibrium
Because concentrations become constant, equilibrium is sometimes called steady state

7. Equilibrium
Reactions do not stop at equilibrium, forward & reverse reaction rates become equal

9. Reaction aA(aq)+ bB(aq) cC(aq)+ dD(aq) Ratef = kf[A]a[B]b
Rater = kr[C]c[D]d
At equilibrium, Ratef = Rater
kf[A]a[B]b = kr[C]c[D]d

10. kf[A]a[B]b = kr[C]c[D]d
At equilibrium, Ratef = Rater
kf[A]a[B]b = kr[C]c[D]d
kf /kr = ([C]c[D]d)/ ( [A]a[B]b)
kf /kr = Kc = Keq in terms of concentration
Kc = ([C]c[D]d)/ ( [A]a[B]b)

11. aA(g)+ bB(g)<-->cC(g)+ dD(g)
Reaction
aA(g)+ bB(g)<-->cC(g)+ dD(g)
Ratef = kfPAaPBb
Rater = krPCcPDd
At equilibrium, Ratef = Rater
kfPAaPBb = krPCcPDd

12. At equilibrium, Ratef = Rater
kfPAaPBb = krPCcPDd
kf /kr = (PCcPDd)/ ( PAaPBb)
kf /kr = Kp = Keq in terms of pressure
Kp = (PCcPDd)/ ( PAaPBb)

13. All Aqueous
aA + bB pP + qQ

15. Equilibrium Expression
( Products)p
(Reactants)r
Keq=

16. AP CHM HW
Read: Chapter 12
Work problems: 5, 7, & 12
Page: 365

17. CHM II HW
Read: Chapter 17
Work problems: 17 & 21
Page: 745

18. Equilibrium Applications
When K >1, [p] > [r]
When K <1, [p] < [r]

19. Equilibrium Calculations
Kp = Kc(RT)Dngas

20. Equilibrium Expression
Reactants or products not in the same phase are not included in the equilibrium expression

21. Keq= [C]c [D]d [B]b Equilibrium Expression
aA(s)+ bB(aq)<--> cC(aq)+ dD(aq)
[C]c [D]d
[B]b
Keq=

22. Sequence of steps that make up the total reaction process
Reaction Mechanism
Sequence of steps that make up the total reaction process

23. Reaction Mechanism 1) A + B <---> C Fast
2) A + C <---> D Fast
3) B + D <---> H Fast
4) H + A -----> P Slow

24. Reaction Mechanism The rate determining step is the slowest step
H + A ----> P Slow
Rate = k4[H][A]

25. Reaction Mechanism Rate = k4[H][A]
Because H is not one of the original reactants, H cannot be used in a rate expression

26. K3 = [H]/([B][D]) [H] = K3[B][D] Reaction Mechanism

27. Reaction Mechanism
[H] = K3[B][D]
Rate = k4[H][A]
Rate = k4K3[B][D][A]

28. K2 = [D]/([A][C]) [D] = K2[A][C] Reaction Mechanism

29. Reaction Mechanism [D] = K2[A][C] Rate = k4K3[B][D][A]
Rate = k4K3[B]K2[A][C][A]
Rate = k4K3 K2[B][A]2[C]

30. K1 = [C]/([A][B]) [C] = K1[A][B] Reaction Mechanism

31. Reaction Mechanism [C] = K1[A][B] Rate = k4K3 K2[B][A]2[C]
Rate = k4K3 K2[B][A]2K1[A][B]
Rate = k4K3 K2K1 [B]2[A]3
Rate = K [B]2[A]3

32. Solve Rate Expression 1) A + B <---> 2C Fast
2) A + C <---> D Fast
3) B + D <---> 2H Fast
4) 2H + A ----> P Slow

33. Reaction Mechanism
When one of the intermediates anywhere in a reaction mechanism is altered, all intermediates are affected

34. Reaction Mechanism
1) A + B <---> C + D
2) C + D <---> E + K
3) E + K <---> H + M
4) H + M <----> P

35. Lab Results % RT WR

36. Applications of Equilibrium Constants
where [A], [B], [P], and [Q] are molarities at any time.
Q = K only at equilibrium.

37. NH H2 + N2
At a certain temperature at equilibrium Pammonia = 4.0 Atm, Phydrogen = 2.0 Atm, & Pnitrogen = 5.0 Atm.
Calculate Keq:

38. Equilibrium Applications
When K > Q, the reaction goes forward
When K < Q, the reaction goes in reverse

39. Drill: SO2 + O2 SO3
Determine the magnitude of the equilibrium constant & the partial pressure of each gas is Atm.

40. Le Chatelier’s Principle
If stress is applied to a system at equilibrium, the system will readjust to eliminate the stress

41. LC Eq Effects
A(aq) +2 B(aq) <--->
C(aq) + D(aq) + heat
Write equilibrium exp:
What happens if:

42. LC Eq Effects
2 A(aq) + B(s) <--->
C(aq) +2 D(aq) + heat
Write equilibrium exp: What happens if:

43. LC Eq Effects
2 A(g) + 2 B(g) <--->
3 C(g) + 2 D(l)
What happens if:

44. Drill: Write the equilibrium expression & solve when PNO2 & PN2O4 = 50 kPa each:
N2O4(g) 2 NO2(g)

45. Equilibrium Applications
DG = DH - TDS
DG = - RTlnKeq

46. Equilibrium Calculations
aA + bB <--> cC + dD
Stoichiometry is used to calculate the theoretical yield in a one directional rxn

47. Equilibrium Calculations
aA + bB <--> cC + dD
In equilibrium rxns, no reactant gets used up; so, calculations are different

48. Equilibrium Calculations
Set & balance rxn
Assign amounts
Write eq expression
Substitute amounts
Solve for x

49. Equilibrium Calculations
CO + H2O CO2 + H2
Calculate the partial pressure of each portion at eq.when kPa CO & 50.0 kPa H2O are combined:
Kp = 3.4 x 10-2

50. AP CHM HW
Read: Chapter 12
Problems: 37 & 39
Page: 367

51. CHM II HW
Read: Chapter 17
Problems: 45
Page: 747

52. Equilibrium Calculations
CO + H2O CO2 + H2
Calculate the partial pressure of each portion when 100 kPa CO & 50 kPa H2O are combined:
Kp = 3.4 x 10-2

53. Equilibrium Calculations
CO H2O CO2 H2
100 -x 50 - x x x
Kp = PCO2PH2 = x2
PCOPH2O (100-x) (50-x)
Kp = 3.4 x 10-2

54. Equilibrium Calculations
x x2
(100 -x)(50 - x) = x + x2
= 3.4 x 10-2
x2 = x x2
0.966x x = 0

55. Equilibrium Calculations
Xe (g) + F2(g) XeF2(g)
Calculate the partial pressure of each portion when 50.0 kPa Xe & kPa F2 are combined:
Kp = 4.0 x 10-4

56. A(aq)+ 2 B(aq) C(s)+ 2 D(aq)
Drill: Solve for K
A(aq)+ 2 B(aq) C(s)+ 2 D(aq)
Calculate Keq if:
[A] = 0.30 M [B] = 0.20 M
C = 5.0 g [D] = 0.30 M

57. A(aq)+ B(aq) D(aq) Drill:
Calculate the equilibrium concentration of each species when equal volumes of
0.40 M A & 0.20 M B are combined.
Keq = 0.50

58. Equilibrium Calculations
Xe (g) + 2 F2(g) XeF4(g)
Calculate the partial pressure of each portion when 75 kPa Xe & 20.0 kPa F2 are combined:
Kp = 4.0 x 10-8

59. Drill:
A + B C + D
Calculate the equilibrium concentration of each species when equal volumes of
0.60 M A & 0.80 M B are combined.
Keq = 0.50

60. The Test on Rxn Rates & Chemical Equilibria will be on Tuesday

61. Working with Equilibrium Constants

62. When adding Reactions
Multiply Ks

63. A B K1
B C K2
A C K3
K3 = (K1)(K2)

64. Solve K for each:
A + B C + D
C + D P + Q
A + B P + Q

65. When doubling Reactions
Square Ks

66. A B K1
2 A 2 B K2
K2 = (K1)2

67. When a rxn is multiplied by any factor, that factor becomes the exponent of K

68. A B K1
1/3 A 1/3 B K2
K2 = (K1)1/3

69. When reversing Reactions
Take 1/Ks

70. A B K1
B A K2
K2 = 1/K1

71. Equilibrium Calculations
Kr (g) + F2(g) KrF2(g)
Calculate the partial pressure of each portion when 40.0 kPa of Kr & 80.0 kPa of F2 are combined:
Kp = 4.0 x 10-2

72. Equilibrium Calculations
Rn (g) + F2(g) RnF2(g)
Calculate the partial pressure of each portion when 50 kPa Rn & 75 kPa F2 are combined:
Kp = 4.0 x 10-2

73. Drill:
A + B P + Q
Calculate the concentration of each portion at equilibrium when mL 0.50 M A is added to 150 mL 0.50 M B:
Kc = 4.0 x 10-2

74. Equilibrium Calculations
I2 + 2 S2O S4O I-
Calculate the concentration of each portion when 100 mL 0.25 M I2 is added to 150 mL 0.50 M S2O3-2:
Kc = 4.0 x 10-8

75. Clausius-Claperon Eq
(T2)(T1) k2
(T2 – T1) k1
Ea= R ln

76. Clausius-Claperon Eq
(T2)(T1) P2
(T2 – T1) P1
Hv= R ln

77. Clausius-Claperon Eq
(T2)(T1) K2
(T2 – T1) K1
DH = R ln

78. DG = DH - TDS DGo = -RTlnK

79. All aqueous
aA + bB pP + qQ
[P]p[Q]q
[A]a[B]b
Kc =
at equilibrium

80. Q = [P]p[Q]q [A]a[B]b All aqueous aA + bB pP + qQ
at the other conditions

81. AP CHM HW
Problems: 41 & 43
Page: 368

82. CHM II HW
Problems: 47
Page: 747

83. Write the Eq Expression
AB(aq) A(aq)+ B(aq)
Calculate [A], [B], & [AB] at equilibrium when [AB] = 0.60 M at the start
Keq = 6.0 x 10-5

84. Calculate the heat of reaction when K =
Drill:
Calculate the heat of reaction when K =
2.5 x 10-6 at 27oC, &
K = 2.5 x 10-4 at 127oC.

85. Drill:
1 A + 1 B Z + 1 Y
Calculate the concentration of each portion at equilibrium when 1.0 L 0.50 M A is added to 1.5 L 0.50 M B:
Kc = 2.0 x 10-2

86. Next Test
Tuesday

87. Drill:
1 A + 1 B Z
Calculate the concentration of each portion at equilibrium when the original solution has 0.50 M A & 0.50 M B:
Kc = 2.0 x 10-2

88. Review

90. Experimental Results Exp # [A] [B] [C] time 1 1.0 1.0 1.0 16

91. Experimental Results Exp # [A] [B] Rate 127 1.0 1.0 2.0 x 10-2

92. Write the Eq Expression
PQ(aq) P(aq)+ Q(aq)
Calculate [P], [Q], & [PQ] at equilibrium when [PQ] = 0.90 M at the start
Keq = 9.0 x 10-5

93. Write the Eq Expression
AB(aq) A(aq)+ B(aq)
Calculate [A], [B], & [AB] at equilibrium when [AB] = 0.60 M at the start
Keq = 6.0 x 10-5

94. Experimental Results Exp # [A] [B] [C] Rate 1 0.1 0.1 0.2 2

95. Reaction Mechanism Step 1 A <--> B fast
Step 2 2 B <--> 3C fast
Step 3 C ---> D slow

96. LC Eq Effects
2 A(aq) + B(s) <--->
C(aq) +2 D(aq) + heat
Write equilibrium exp: What happens if:

97. LC Eq Effects
3 A(g) + B(g) <--->
2 C(g) + 2 D(l)
Write equilibrium exp:
What happens if:

98. A + B <---> C + D
C + H <---> M + N
N + T <---> P + Q
What happens all intermediates if:

99. SO + O2. SO3 Calculate the equilibrium pressures if SO at 80
SO + O2 SO3 Calculate the equilibrium pressures if SO at 80.0 kPa is combined with O2 at 40.0 kPa. K = 0.020

100. 1A + 1B. 1P + 1Q [Ai] = 0. 20 M. Calcu- [Bi] = 0. 30 M
1A + 1B 1P + 1Q [Ai] = 0.20 M Calcu- [Bi] = 0.30 M late the [Pi] = 0.20 M eq con- [Qi] = 0.30 M centra- Kc = tion of ea.