Download SPRING 2002 Test 2 1. Which of the following statements is

SPRING 2002 Test 2
1. Which of the following statements is incorrect?
A. The rate-determining step is always the first step.
B. A unimolecular process is one in which a single molecule dissociates.
C. A bimolecular process is one involving a collision of two molecules.
D. A reaction mechanism is a step-by-step detailed description of a chemical reaction.
E. An elementary process is a step in the reaction mechanism.
Ans. A.
2. What is the rate law for the following mechanism?
CH3COOC2H5 + H2O => CH3C(OH)OC2H5+ + OHCH3C(OH)OC2H5+ => CH3COOH + C2H5+
C2H5+ + OH- => C2H5OH
A.Rate = k[CH3COOC2H5][H2O]2
B.Rate = k[C2H5OH]
C.Rate = k[CH3COOH]
D.Rate = k[CH3COOC2H5]
E.Rate = k[CH3COOC2H5][H2O]
Ans. E
(slow)
(fast)
(fast)
3. A catalyst alters the rate of a chemical reaction by:
A. always providing a surface on which molecules react
B. changing the products formed in the reaction
C. providing an alternate pathway for the reaction with generally lower activation energy
D. changing the frequency of collisions between molecules
E. increasing the number of collisions of molecules
Ans. C
4. For the decomposition of SO3(g), Kc = [SO2]2[O2]/[SO3]2, at equilibrium there are
0.090 mol SO2, 0.110 mol O2, 0.100 mol SO3 in a 25.0 L container. What is the value of
Kc?
A.3.6 x 10-3
B.0.040
C.2.23
D.0.089
E.1.00
Ans. A
5. Write the equilibrium constant expression for the following reaction:
6 CO2(g) + 6 H2O(l) <=> C6H12O6(s) + 6O2(g)
A. Kc = [C6H12O6]/[H2O]6[CO2]6
B. Kc = [O2]/ [CO2]
C. Kc = [CO2]6/[C6H12O6]
D. Kc = [H2O]6[CO2]6/[O2] 6
E. Kc = [O2]6/[CO2]6
Ans. E
6. Consider the equilibrium reaction, N2(g) + O2(g) <=> 2NO(g), where Kc =
[NO]2/[N2][O2]. The equilibrium constant for the reaction, 2N2(g) + 2O2(g) <=> 4NO(g)
is:
A. (1/Kc)4
B. (Kc)4
C. (Kc)1/2
D. (1/Kc)2
E. (Kc)2
Ans. E
7. Which of the following statements is FALSE:
A. At equilibrium, the concentrations of all species are constant
B. The value of the equilibrium constant depends on the temperature
C. At equilibrium, the reaction has stopped
D. At equilibrium, the forward and reverse reactions are happening at the same rate
E. Pure solids are not included in the equilibrium constant expression.
Ans. C
8. For the gaseous reaction, 2 H2 + 2 NO <=> 2 H2O + N2, Kp at 120oC = 2.42. At a
given moment, it is found that the partial pressures of H2, NO, H2O and N2 are 1.1, 1.3,
0.78 and 2.2 atm, respectively. Which of the following statements describes the
situation?
A. Qp = 1.2 so the reaction goes to the right
B. Qp = 1.2 so the reaction goes to the left
C. Qp = 0.65 so the reaction goes to the right
D. Qp = 0.65 so the reaction goes to the left
E. The reaction is at equilibrium
Ans. C
9. The reaction, I2(g) + IF3(g) <=> 3 IF(g), is performed by mixing 2.00 moles of I2 and
3.00 moles of IF3 in a 1 L container at 160 oC. At equilibrium, there are 0.330 moles of
IF present in the container. Calculate the value of Kc at this temperature.
A. 0.055
B. 5.99 x 10-3
C. 6.58 x 10-3
D. 152
E. 18.2
Ans. C
10. The gaseous disproportionation of ClF to give Cl2 and F2, 2 ClF <=> Cl2 + F2, has a
Kp at 50 oC of 25.0. If a sample of ClF that is at a pressure of 2.2 atm is allowed to react,
what will be the equilibrium partial pressure of Cl2?
A. 1.00 atm
B. 1.08 atm
C. 1.83 atm
D. 2.00 atm
E. 2.12 atm
Ans. A
11. For which of the following gaseous reactions will the values of Kp and Kc be the
same?
A. 2 NO + O2 <=> 2 NO2
B. N2 + 3H2 <=> 2 NH3
C. 2 CO + O2 <=> 2 CO2
D. N2O4 <=> 2 NO2
E. N2 + O2 <=> 2 NO
Ans. E
12. Consider the exothermic reaction between N2 and H2 to produce NH3. In order to
produce as much NH3 as possible, this reaction should be run at
A. low temperature and low pressure
B. low temperature and high pressure
C. high temperature and low pressure
D. high temperature and high pressure
E. impossible to say
Ans. B
13. The pH of blood is 7.40. What is the [OH-] concentration?
A. 4.0 x 10-8
B. 2.0 x 10-8
C. 5.2 x 10-9
D. 2.5 x 10-7
E. 4.7 x 10-8
Ans. D
14. The self-ionization of water is temperature dependent. If, at a given temperature, the
value of Kw is 1.0 x 10-12, what is the pH of neutral water at this temperature?
A. 7.0
B. 7.5
C. 6.0
D. 6.5
E. 7.2
Ans. C
15. Which of the following is the strongest acid?
A. HClO2
B. HNO2
C. HClO3
D. HSO4E. H2SO4
Ans. E
16. For each group of compounds listed, which is the strongest acid?
I. HIO2, HIO3, HIO4
II. H2Se, H2S, H3As
III. HPO2, HClO2, HBrO2
A. I. HIO2, H2Se, HBrO2
B. I. HIO4, H2Se, HBrO2
C. I. HIO2, H3As, HPO2
D. I. HIO3, H3As, HClO2
E. I. HIO4, H2Se, HClO2
Ans. E
17. A 0.0120 M solution of an organic acid has a pH of 3.39. Calculate the value of Ka of
this acid.
A. 1.4 x 10-5
B. 2.8 x 10-5
C. 1.4 x 10-4
D. 3.2 x 10-4
E. 3.2 x 10-5
Ans. A
18. Vitamin C is a diprotic acid. Calculate the pH of a 0.100 M solution of vitamin C
given that Ka1 = 7.9 x 10-5 and Ka2 = 1.6 x 10-12
A. 12.8
B. 11.7
C. 7.84
D. 6.57
E. 2.55
Ans. E
19. What is the pH of a 7.5 x 10-3 M solution of morphine if Kb of morphine = 1.6 x 10-6?
A.3.66
B. 3.96
C. 4.37
D. 5.72
E. 10.04
Ans. E
20. According to the Lewis formulation of acids and bases
A. An acid increases the [H+] in water
B. A base is a source of OHC. A base is a donor of electrons
D. An acid is a donor of protons
E. none of the above
Ans. C