1.
The data given below are obtained at 55°C for the following reaction:

              (CH3)3CBr(aq) + OH–(aq) → (CH3)3COH(aq) + Br–(aq)
 
[(CH3)3CBr]0
[OH–]0
Inital Rate
Exp.
(mol L-1)
(mol L-1)
(mol L-1 s-1)
1
0.10
0.10
1.0 × 10-3
2
0.20
0.10
2.0 × 10-3
3
0.10
0.20
1.0 × 10-3
4
0.30
0.20
?

What will the initial rate (in mol L-1 s-1) be in Experiment 4?
A.
3.0 × 10–3
B.
6.0 × 10–3
C.
9.0 × 10–3
D.
18 × 10–3
E.
1.1 × 10–3


2.
The reaction

   

exhibits the rate law

   

where k = 1.0 10-5 M-1 s-1 at 25oC. If the initial concentration of NOBr was 1.79 10-1 M, calculate the half-life for this reaction?
A.
1.8 10-6 s
B.
8.9 103 s
C.
9.0 10-6 s
D.
5.6 105 s
E.
3.6 10-8 s


3.
A first-order reaction is 40.0% complete at the end of 35.2 minutes. What is the value of the rate constant (in min-1)?
A.
2.60 10-2
B.
1.45 10-2
C.
6.89 101
D.
3.84 101
E.
1.97 10-2


4.
For the reaction
   
 
Cl2 (g) + H2S (g) → S (g) + 2 HCl (g)
 
a reaction mechanism consistent with the rate expression is,
 
 
 
 
 
 
Step 1:     Cl2 + H2S   → HS- + HCl + Cl+             (slow)
 
 
 
Step 2:    Cl+ + HS- → S      + HCl                       (fast)
     
The overall order of the reaction is,
A.
4
B.
1
C.
3.5
D.
2.5
E.
2


5.
Which one of the following statements is TRUE?
A.
The rate of zero order reaction changes with concentration.
B.
The rate constant is dependent on the order of the reaction.
C.
The activation energy is dependent on the temperature of the reaction.
D.
A catalyst can shift the equilibrium position of the reaction.
E.
The rates of most reactions change as the reaction proceeds.


6.
Consider the gaseous reaction CO(g) + Cl2(g) COCl2(g). What is the expression for Kp in terms of K?
A.
K(RT)
B.
K/(RT)
C.
K(RT)2
D.
K/(RT)2
E.
1/K(RT)


7.
For the reaction below, Kp = 1.16 at 800. oC.

   

If a 27.6 gram sample of CaCO3 is placed in a 10.0 L container and heated to 800.oC, what percent of the CaCO3 will react to reach equilibrium?
A.
24.7 %
B.
47.8 %
C.
64.1 %
D.
30.7 %
E.
34.5 %


8.
Considering the following equilibrium:

2SO2(g) + O2(g) 2SO3(g) + heat

More of SO3 will be formed, if
A.
the temperature is increased.
B.
the volume of the reaction flask is decreased.
C.
oxygen is removed from the reaction flask.
D.
the volume of the reaction flask is increased.
E.
an inert gas is added to the reaction flask.


9.
Consider the reaction At 1273 K, the Kp value is 167.5. What is the at equilibrium if the is 0.44 atm at this temperature?
A.
4.3 atm
B.
0.45 atm
C.
17 atm
D.
8.6 atm
E.
12 atm


10.
For the following reaction:

   

Initially there are 0.10 moles of N2O and 0.25 moles of N2H4, in a 10.0 L container. If there are 0.035 moles of N2O at equilibrium, how many moles of N2 are present at equilibrium?
A.
3.3 10-2 moles
B.
6.5 10-2 moles
C.
9.8 10-2 moles
D.
2.0 10-1 moles
E.
7.0 10-6 moles


11.
Ammonia is prepared industrially by the reaction:

N2(g) + 3H2(g) 2NH3(g)

For this reaction, ΔH° = –92.2 kJ and K (at 25°C) = 4.0 × 108. When the temperature of the reaction is increased to 500°C, which one of the following statements is TRUE?
A.
K for the reaction will be larger at 500°C than at 25°C.
B.
At equilibrium, more NH3 is present at 500°C than at 25°C.
C.
As the temperature is raised, less ammonia will be formed.
D.
The reaction of N2 with H2 to form ammonia is endothermic.
E.
The equilibrium position of the reaction will not change.


12.
The acid dissociation constants (Ka) for HCN and HF in H2O at 25°C are 6.2 × 10–10 and 7.2 × 10–4, respectively. The relative order of base strengths is:
A.
F– > H2O > CN–
B.
H2O > F– > CN–
C.
CN– > F– > H2O
D.
F– > CN– > H2O
E.
CN– > H2O > F–


13.
Solid calcium hydroxide, Ca (OH)2, is dissolved in water until the pH of the solution is 10.74. The concentration of the Ca(OH)2 solution is:
A.
1.8 10-11 M
B.
1.1 10-3 M
C.
2.7 10-4 M
D.
1.5 10-7 M
E.
2.1 10-6 M


14.
Calculate the [H+] in a 0.093 M solution of HCN, Ka = 6.2 10-10.
A.
9.3 10-2 M
B.
7.6 10-6 M
C.
5.8 10-11 M
D.
1.5 10-5 M
E.
4.3 10-3 M


15.
Consider acids and bases, which one of the following statements is FALSE?
A.
an aqueous solution of 0.1 M NaF is basic.
B.
SO42- is the conjugate base of H2SO4
C.
A solution that resists changes in its pH is known as a buffer solution.
D.
A solution of pH = 0.0 is an acidic solution.
E.
Al3+ ion in an aqueous solution behaves as a Lewis acid.


16.
A weak acid, HA, is 1.0% dissociated in 0.010 M solution of HA. The Ka of this acid is
A.
5.1 x 10-4
B.
1.0 x 10-6
C.
2.1 x 10-3
D.
1.0 x 10-2
E.
1.3 x 10-4


17.
Calculate the pH of a solution made by mixing 100.0 mL of 0.782 M NH3 with 100.0 mL of 0.100 M HCl. (Kb for NH3 = 1.8 10-5.)
A.
10.09
B.
3.91
C.
8.42
D.
9.21
E.
11.11


18.
If 25.0 mL of 0.750 M HCl are added to 100. mL of 0.209 M NaOH, what is the final pH?
A.
12.2
B.
1.76
C.
13.2
D.
0.780
E.
7.21


19.
A 0.210 g sample of an acid (molar mass = 192 g mol-1) is titrated completely with 30.5 mL of 0.108 M NaOH to a phenolphthalein endpoint. The formula of the acid is:
A.
HA
B.
H2A
C.
H3A
D.
H4A
E.
H5A


20.
The solubility in mol/L of Ag2CrO4 is 1.2 10-4 M. Calculate the Ksp for this compound.
A.
2.9 10-8
B.
1.2 10-4
C.
6.9 10-12
D.
1.7 10-12
E.
2.4 10-4


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