KING FAHD UNIVERSITY OF PETROLEUM AND MINERALS
CHEMISTRY DEPARTMENT
CHEM-102-112 FIRST MAJOR EXAM
001
TEST CODE NUMBER
STUDENT NUMBER:
_____________________________
NAME :
_____________________________
SECTION NUMBER:
_____________________________
INSTRUCTIONS
1.
2.
3.
4.
5.
6.
Write your student number, name, and section number on the EXAM COVER page.
Write your student number, section number, and your name on your EXAM ANSWER
FORM.
Bubble in pencil your student number and your section number on the EXAM ANSWER
FORM.
Bubble in pencil on your EXAM ANSWER FORM the correct answer to each of the
questions. .
You must not give more than ONE answer per question.
At the end of the exam return the EXAM ANSWER FORM to the proctor.
The exam contains 20 multiple choice questions and the time allowed is 80 min.
PLEASE TURN OFF YOUR CELL PHONE AND
PLACE IT UNDER YOUR SEAT
Important constants
Gas Constant (R)
Planck’s Constant (h)
Velocity of light (c)
Avogadro’s number (N)
Bohr’s Constant (RH)
Faraday (F)
Specific heat of H2O
= 0.08206
= 8.314
= 8.31 x 107
= 6.626 x 10-34
= 6.626 x 10-34
= 2.998 x 108
= 6.022 x 1023
= 2.179 x 10-18
= 96485
= 4.18
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L.atm/(mol.K)
J/(mol.K)
g.cm2/(sec2.mol.K)
J.sec/particle
kg.m2/(sec.particle)
m/sec
particles/mole
J/particle
Coulombs
J/(g.oC)
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Name: __________________________ Date: _____________
1. The law of mass action to determine the equilibrium expression for the reaction
2NO2Cl
2NO2 + Cl2
is:
A) [NO2Cl]2 / [NO2]2 [Cl2]
B) 2[NO2Cl] / 2[NO2] [Cl2]
C) [NO2]2 [Cl2] / [NO2Cl]2
D) 2[NO2] [Cl2] / 2[NO2Cl]
2. Which of the following statements is not true?
A) Dissociations of strong acids and bases are not treated as equilibria but rather as
processes that go to completion.
B) The value of Ka can not be calculated for a solution involving weak bases.
C) Because the ionization of a strong acid is almost complete, the concentration of
H3O+ ion at equilibrium is equal to the starting concentration of the strong acid.
D) A very low pOH value is expected for a relatively concentrated solution of a
strong base.
3. For the reaction:
2 H2 + O2 
2 H 2O ,
if [H2] initially was 4.5 M and became 0.053 M after 0.5 hours, what is the average
rate (in M/s) of the reaction over that period?
A)
B)
C)
D)
2.9  10-5
0.15
8.9
2.5  10-3
4. For the polyprotic weak acid H3A, which of the following order in terms of acidity
strength (from strongest to weakest) is correct?
A)
B)
C)
D)
H3A (aq) > H2A− (aq) > HA2− (aq)
HA2− (aq) > H2A− (aq) > H3A (aq)
H2A− (aq) > HA2− (aq) > H3A (aq)
HA2− (aq)  H2A− (aq) > H3A (aq)
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5. Which one of these compounds will form a basic solution when dissolved in water?
A)
B)
C)
D)
NaClO2
AlCl3
As2O5
NH4NO3
6. The conjugate base of HS‒ is:
‒
A)
B)
C)
D)
HS itself.
+
H3S
H2S
S2‒
7. What is the pH of a 0.50 M triethylamine, (C2H5)3N, solution?
Kb for triethylamine is 5.3  10-4.
A)
B)
C)
D)
10.68
5.32
12.21
1.79
8. The reaction:
A + 2B+ C  D+ 2E
produces the following initial rates when starting reactant concentrations are varied.
Trial
Initial rate
(M/s)
Starting concentrations (M)
[A]
[B]
[C]
1
-2
2.42  10
0.0100
0.0100
0.0200
2
4.83  10-2
0.0200
0.0100
0.0200
3
19.4  10-2
0.0100
0.0200
0.0200
4
-2
0.0100
0.0100
0.0400
9.71  10
The correct rate law is:
A)
B)
C)
D)
rate = k [A] [B]4 [C]2
rate = k [A] [B]3 [C]2
rate = k [A] [B]2 [C] [D] [E]2
rate = k [A] [B]2 [C]
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9. For the following system at equilibrium:
N2(g) + 3H2(g)
2NH3(g)
o
ΔH = +92.94 kJ ,
which of the eight changes below will shift the equilibrium to the right?
I. increasing the temperature
II. decreasing the temperature
III. increasing the volume
IV. decreasing the volume
V. removing some NH3
VI. adding some NH3
VII. removing some N2
VIII. adding some N2
A)
B)
C)
D)
I, VI, VIII
I, III, V, VII
II, IV, V, VIII
II, III, V, VIII
10. What is the pOH of a solution made up by dissolving 3.2  10-3 mol of HClO3 in
enough water to make 540 milliliters of solution?
A)
B)
C)
D)
- 2.23
8.77
2.23
11.77
11. The reaction:
2HI (g)
H2 (g)
+
I2 (g)
has KP = 0.040 at 25°C. If 0.409 mol of pure HI is isolated in a 10.0-L container at
25°C, the equilibrium partial pressure of H2 at 25°C will be:
A)
B)
C)
D)
0.16 atm
0.14 atm
0.020 atm
0.075 atm
12. Which of the following is correct regarding the relationship between Q and K for a
given chemical reaction?
A)
B)
C)
D)
If Q < K then some of the products must be converted to reactants.
If Q > K then more of the products must be consumed.
If Q > K then some of the reactants must be converted to products.
If Q < K then more of the reactants are produced.
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13. Consider the following two equilibria:
2SO3(g)
2NO3(g)
Kc = 2.3 x 10-7
Kc = 0.40 x 10-2
2SO2(g) + O2(g)
2NO2(g) + O2(g)
Calculate the equilibrium constant for the reaction:
SO2(g) + NO3(g)
A)
B)
C)
D)
SO3(g) + NO2(g)
7.5  10–3
1.7  104
78
1.3  102
14. A gaseous compound A dissociates according to the following:
A(g)
B(s)
+
C(g)
In an experiment running at temperature T, the compound A dissociates until it
reaches an equilibrium pressure of 0.19P, where P is the total pressure of the
reaction mixture. At temperature T, the equilibrium constant (KP) of the reaction
above is:
A)
B)
C)
D)
4.3
0.86
0.23
2.1
15. The rate of a specific reaction is doubled when the temperature is raised from
‒ 2.1°C to 2.2°C. The activation energy (Ea) of the reaction is:
A)
B)
C)
D)
9.9  102 J
1.3  102 kJ
2.4  103 J
1.0  102 kJ
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16. Which of the following statements best describes the condition needed for a
successful formation of a product according to the collision theory?
A) The relative orientation of the particles has little or no effect on the formation of
the product.
B) The relative orientation of the particles has an effect only if the kinetic energy
of the particles is below the minimum needed value.
C) The energy of the incoming particles must be above a certain minimum value
and the relative orientation of the particles must allow for formation of new
bonds in the product.
D) The relative orientation of the incoming particles is the only requirement for
formation of the new bonds in the product.
17. A 1.00 M solution of a weak monoprotic acid undergoes 1.5 % dissociation. What
is the percent dissociation of a 0.25 M solution of this acid?
A)
B)
C)
D)
6.0 %
0.90 %
1.5 %
3.0 %
18. If the reverse reaction is favored (preferable), the value of the equilibrium constant
(K) for the reverse reaction will be:
A)
B)
C)
D)
always approaching infinity ( ).
more than the K value for the forward reaction.
almost the same as the K value for the forward reaction.
less than the K value for the forward reaction.
19. The reaction:
aA

products
is first order with a rate constant of 1.68 x 10 2 s 1 at 25°C. If 2.50 mol of A is
placed in a 5.0 L container maintained at 25°C, how many moles of A will remain
after 1.0 minute?
A)
B)
C)
D)
0.50
1.2
0.18
0.91
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20. The rate constant for the reaction:
3A
→ 2B
is 0.0447 hr -1. If the initial concentration of A is 0.050 M, what is the half-life of the
reaction?
A)
B)
C)
D)
15.5 hr
44.7 hr
5.23  104 hr
5.59 hr
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Answer Key
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
C
B
D
A
A
D
C
B
C
D
B
B
D
A
D
C
D
B
C
A
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