[A] = [A]0 - kt
t1/2 = [A]0/2k
[A] = [A]0e-kt
ln[A] = ln[A]0 - kt
t1/2 = ln2/k
1/[A] = 1/[A]0 + kt
t1/2 = 1/k[A]0
lnk = lnA - Ea/RT
ln(k2/k1) = - (Ea/R)(1/T2 - 1/T1)
Kp = Kc(RT)Δn
ln(K2/K1) = - (ΔHo/R)(1/T2 - 1/T1)
 



1.
Consider the following reaction
        6A(g)   +   3B(g)   →   6C(g)   +   11D(g)
If [A] is decreasing at the rate of 1.68 mol L-1s-1, at what rate is [D] changing?
A.
3.08 mol L-1s-1
B.
3.61 mol L-1s-1
C.
4.25 mol L-1s-1
D.
4.84 mol L-1s-1
E.
1.74 mol L-1s-1


2.
For the reaction 4A + 2B → 2C + D, the following initial rate data were collected at constant temperature. Determine the correct rate law for this reaction. All units are arbitrary.
Trial
Initial [A]
Initial [B]
Initial Rate
1
0.308
0.283
15.92
2
0.308
0.688
15.92
3
0.723
0.688
37.38
 
A.
Rate = k [A]2
B.
Rate = k [A]
C.
Rate = k [A] [B]
D.
Rate = k [A]2 [B]
E.
Rate = k [B]2


3.
When the reaction A   →   B   +   C is studied, a plot of 1/[A] versus time gives a straight line with a positive slope. What is the the order of the reaction?
A.
first
B.
zero
C.
second
D.
third
E.
More information is needed to determine the order.


4.
The the units of the rate constant for the reaction A + B → C + D are L mol-1 s-1. What is the overall order of the reaction?
A.
third
B.
zero
C.
first
D.
second
E.
none of the above


5.
The rate law for the reaction 3A → B is rate = k[A]2 with a rate constant of 2.52 L mol-1 s-1. If the initial concentration of A is 0.865 mol/L, what is the half-life of the reaction?
A.
0.275 s
B.
0.172 s
C.
0.551 s
D.
0.315 s
E.
0.459 s


6.
The rate law for the reaction A → B + C is rate = k[A]2 with a rate constant k = 0.3456 L mol-1 s-1. If the initial concentration of A is 0.443 mol/L, calculate its concentration 3.49 seconds after the start of the reaction.
A.
0.289 mol/L
B.
0.310 mol/L
C.
0.247 mol/L
D.
0.372 mol/L
E.
0.211 mol/L


7.
A particular radioactive isotope undergoes a first order decay with a half-life of 37.3 years. How long would it take for the concentration of this isotope to drop to 47.3 % of its original value?
A.
44.1 years
B.
40.3 years
C.
48.3 years
D.
31.3 years
E.
56.2 years


8.
The activation energy of a reaction is 115.0 kJ/mol. If the reaction is exothermic with ΔH = –43.0 kJ/mol, what is the activation energy of the reverse reaction?
A.
–158.0 kJ/mol
B.
72.0 kJ/mol
C.
158.0 kJ/mol
D.
–72.0 kJ/mol
E.
None of the above


9.
The experimental rate law for the reaction A + 2B → D + E is Rate = k[A][B]. Which of the following statements is correct for the mechanism suggested below?
         A + B → C + D      (slow)
         C + B → E                 (fast)
A.
The mechanism is consistent with the rate law and it is physically reasonable
B.
The mechanism is consistent with the rate law but it is not physically reasonable
C.
The mechanism is not consistent with the rate law
D.
The mechanism should only have a single step
E.
None of the above is correct


10.
Which of the following statements is true?
A.
A catalyst accelerates a reaction and is consumed in it.
B.
A catalyst accelerates a reaction by increasing its activation energy.
C.
A catalyst accelerates a reaction by increasing the number of molecular collisions.
D.
A catalyst accelerates a reaction by changing the reaction pathway.
E.
A catalyst accelerates a reaction by supplying energy to the reactant molecules.


11.
Which of the following statements about the reaction quotient, Q, and the equilibrium constant, K, is true?
A.
Q depends on the current concentrations of reactants and products.
B.
K is independent of temperature.
C.
At equilibrium Q reaches a maximum.
D.
K is affected by the total pressure.
E.
K is affected by the presence of a catalyst but Q is not.


12.
What is the mass-action expression, Kc , for the following chemical reaction?
          PbO(s)   +   CO(g)   ↔   Pb(l)   +   CO2(g)
A.
B.
C.
D.
E.
None of the above expressions is correct.


13.
The equilibrium constant, Kc , for the reaction 3A(g) + 2B(g) ↔ C(g) + D(g) is 4.74 at a certain temperature. What is the equilibrium constant for the following reaction at the same temperature?
      1/2 C(g)   +   1/2 D(g)   ↔   3/2 A(g)   +    B(g)
A.
0.0445
B.
2.37
C.
0.570
D.
0.459
E.
1.54


14.
At 25oC, the equilibrium constant, for the reaction
        A(g) ↔ B(g) + C(g)
is Kc = 2.2. What is the value of Kp? (R = 0.08206 L⋅atm/mol⋅K)
A.
47.9
B.
66.0
C.
53.8
D.
40.1
E.
77.2


15.
At 25oC, the equilibrium constant for the reaction
        3A(g) ↔ B(g) + C(g)
is Kp = 0.0455. If the three gases are mixed in a rigid container having partial pressures of 2.19, 1.27 and 0.662 atm for A, B and C, respectively, is the system at equilibrium?
A.
The system is at equilibrium.
B.
The forward reaction must proceed to establish equilibrium.
C.
The volume of the container must be known to answer the question.
D.
The concentrations of all substances must be known to answer the question.
E.
The reverse reaction must proceed to establish equilibrium.


16.
Compounds A, B, and C react according to the following equation
        2A(g)   +   B(g)   ↔   3C(g)
At 100°C a mixture of these gases at equilibrium showed that [A] = 1.69 M, [B] = 1.76 M, and [C] = 1.30 M. What is the value of Kc for this reaction?
A.
0.437
B.
0.408
C.
0.503
D.
0.344
E.
0.595


17.
At a certain temperature, the equilibrium constant for the reaction
        CO2(g)   +   H2(g)   ↔   CO(g)   +   H2O(g)
is Kc = 4.31. If 3.00 mol of CO2 and 3.00 mol of H2 are placed in a 3.00 L vessel and equilibrium is established, what will be the concentration of carbon monoxide?
A.
0.714 M
B.
0.675 M
C.
0.573 M
D.
0.532 M
E.
0.941 M


18.
At a certain temperature, the equilibrium constant for the reaction
        2NaHCO3(s)   ↔   Na2CO3(s)   +   H2O(g)   +   CO2(g)
is Kp = 0.210. If a sufficient quantity of NaHCO3(s) is placed in a closed container at this temperature, what would be the partial pressure of carbon dioxide after equilibrium is established?
A.
0.501 atm
B.
0.386 atm
C.
0.458 atm
D.
0.595 atm
E.
0.329 atm


19.
When solid magnesium hydroxide is added to water, part of it dissociates into magnesium and hydroxide ions.
        Mg(OH)2(s)   ↔   Mg2+(aq)   +   2OH–(aq)
If the above reaction is at equilibrium at a certain temperature, what would be the effect of adding a small amount of hydroxide ions to the solution?
A.
No effect.
B.
The forward reaction will proceed to establish equilibrium.
C.
The solution will become supersaturated.
D.
The reverse reaction will proceed to establish equilibrium.
E.
None of the above conclusions is justified without additional information.


20.
Consider the following reaction.
        2A(g) + B(g) ↔ C(g)          ΔHºrxn = 159 kJ/mol
Under which reaction conditions would you expect to have the greatest equilibrium yield of C(g)?
A.
high temperature, high pressure
B.
low temperature, high pressure
C.
high temperature, low pressure
D.
low temperature, low pressure
E.
none of the above, unless a catalyst is present


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