CHEMISTRY 102, FINAL EXAM (a)
Helpful items:
R = 8.314 J/mol·K
ln x = 2.303 log x
o
ΔG o = −nFE cell
F = 96,500 J/V·mol
RT
0.0592V
o
E cell
=
ln K o =
log K o
n
nF
ΔG o = ΔH o − TΔS o
ΔG = ΔG o + RT ln Q
Integrated rate laws:
[ A]t = − kt + [ A]o
ln[ A]t = −kt + ln[ A]o
1
1
= kt +
[ A]t
[ A]o
1
1
= 2kt +
2
[ A]t
[ A]o2
Arrhenius equation:
k = A e(-Ea/RT).
1. What is the letter in parentheses to the right of the title on the line at the top of this page?
a. a
b. b
c. c
d. d
e. e
2. Which compound is an alcohol?
a. C6H5-O-C6H5
b. CH4
c. CH3NH2
d. C2H6
e. CH3OH
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3. How many grams of sugar, C12H22O11, are present in 0.500 moles of sugar?
a. 1.46 × 10-3 g
b. 0.500 g
c. 171 g
d. 6.84 × 103 g
e. 3240 g
4. If a 45.0 mL sample of 2.20 M Na2SO4 is diluted to yield a final solution that is 0.110 M in
sodium ions, what is the volume of the final solution?
a. 110 mL
b. 450 mL
c. 900 mL
d. 1800 mL
e. 4500 mL
5. Determine the formula for an alkyne, alkene and alkane containing 3 carbons.
a. C3H3 C3H6 C3H4
b. C3H6 C3H8 C3H10
c. C3H4 C3H8 C3H6
d. C3H4 C3H6 C3H8
e. C3H6 C3H10 C3H8
6. Which of the following is a chiral molecule or is associated with chiral molecules?
a. methane
b. ethane
c. Br2C=CBr2
d. ethylene
e. bromochlorofluoromethane
7. Consider the carbon skeleton shown below. To form a primary alcohol, the functional group
can be bonded to which carbon atom(s)?
a. 4
1 C
b. 2 or 6
c. 3, 5, or 6
C
C
C
C
C
C
d. 1, 2, or 7
e. any of them
2
3
4
5
6
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8. Which group contains only examples of addition polymers?
a. polystyrene, polypropylene, polyvinylchloride
b. polypropylene, polyamide, polysaccharide
c. polyamide, polyester, polyvinylchloride
d. polyester, polystyrene, polyisoprene
e. polyamide, polyester
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9. The peptide linkage found in proteins is chemically the same as a(an)
a. ionic bond.
b. double bond.
c. ester linkage.
d. amide linkage.
e. hydrogen bond.
10. Which group includes only endothermic processes?
a. freezing, vaporization, deposition
b. freezing, condensation, deposition
c. melting, condensation, deposition
d. melting, evaporation, sublimation
e. melting, condensation, sublimation
11. The temperature at point c is the
a. critical point.
b. triple point.
c. freezing point.
d. melting point.
e. boiling point.
12. In face-centered cubic unit cells, ___ of the atom on each face of the unit cell is counted as
part of that unit cell.
a. all
b. none
c. 1/2
d. 1/4
e. 1/8
13. Doping silicon with ________ creates __________ silicon because __________.
a. arsenic; n-type; it creates holes that become the charge carriers.
b. arsenic; p-type; it adds extra electrons that become the charge carriers.
c. gallium; p-type; it creates holes that become the charge carriers.
d. gallium; n-type; it adds extra electrons that become the charge carriers.
e. none of the above are correct.
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14. Which of the following is an ionic solid?
a. Aluminum metal;
b. graphite;
c. CH3OH;
d. NaCl
e. H2O.
15. In a reaction that is first-order with respect to reactant A and second-order with respect to
reactant B, the rate of the reaction
a. doubles with a doubling of the concentration of either reactant
b. doubles with a doubling of the concentration of B
c. is halved by a doubling of the concentration of B
d. is tripled by any equal and simultaneous increase in the concentration of A and B
e. quadrupled by a doubling in the concentration of B while the concentration of A is held
constant
16. The rate law for a given reaction is rate = k[reactant]2, with k = 2.64 × 10-4 M-1 min-1. If
the initial concentration is 0.0250 M, what is the initial rate, with the correct units?
a. 4.36 × 10-11 M min-1
b. 1.65 × 10-7 min-1
c. 6.60 × 10-6 M min-1
d. 1.65 × 10-7 M min-1
e. 6.60 × 10-6 min-1
17. The decomposition of N2O(g) to nitrogen and oxygen has the rate law
rate = k[N2O]2
where k = 1.1 x 10-3 M-1 s-1 at 565 oC. If the initial concentration of a sample of N2O is
0.50 M, what is the concentration after one hour at 565 oC?
a. 9.5 x 10-3 M
b. 2.2 x 10-3 M
c. 0.029 M
d. 0.17 M
e. 0.46 M
18. The half-life for the first-order conversion of A to B is 2.22 hr. What is the rate constant?
a. 0.312 hr-1
b. 0.465 hr-1
c. 1.54 hr-1
d. 2.22 hr-1
e. 3.20 hr-1
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19. The rate constant for the reaction, 2 HI(g) → H2(g) + I2(g), doubles on raising the temperature from 410 oC to 425 oC. The activation energy, in J/mol, is
a. 5.3 x 105.
b. 1.8 x 105.
c. 9.1 x 104.
d. 6.7 x 104.
e. - 1.9 x 105.
20. Consider the following reaction mechanism:
Step 1:
2X + Y → W + 2Z
Step 2:
W + Z → W + U + V
Step 3 :
V + Z → 2W + Y
fast
slow
fast
The rate-limiting step in this reaction is Step _____, because _____.
a. 3; the last step is always the rate-limiting step
b. 2; it uses a product of the first step
c. 2; it is the slow step
d. 1; it is bimolecular
e. 1; the first step must occur before any others can occur
21. A chemical reaction reaches equilibrium when
a. both the forward and reverse reactions stop
b. the forward and reverse reactions both occur at the same rate
c. all of the limiting reactant has been used up
d. all of the limiting reactant has been used up and all of the limiting product has been
created
e. the actual yield of the reaction equals the theoretical yield
22. The equilibrium constant for a reaction is related to the rate constants for the reaction as
follows:
a. K = kreverse / kforward
b. K = kforward / kreverse
c. K = kforward x kreverse
d. K = kforward
e. K = kreverse
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23. The reaction given is for all substances in gas phase. The equilibrium constant expression for
this reaction is
4 NH3(g) + 5 O2(g) ⇌ 4 NO(g) + 6 H2O(g)
[ NO] 4 [ H 2 O]6
[ NH 3 ] 4 [O2 ]5
4[ NO ]6[ H 2 O]
b. K c =
4[ NH 3 ]5[O2 ]
a. K c =
[ NH 3 ] 4 [O2 ]5
[ NO] 4 [ H 2 O]6
4[ NH 3 ]5[O2 ]
d. K c =
4[ NO ]6[ H 2 O]
[4 NO][6 H 2 O]
e. K c =
[4 NH 3 ][5O2 ]
c. K c =
COCl2(g) ⇌ CO(g) + Cl2(g)
At equilibrium, [CO] = 4.14 × 10-6 M; [Cl2] = 4.14 × 10-6 M; and [COCl2] = 0.0627 M.
24. Consider the reaction:
Calculate the value of the equilibrium constant, Kc.
a. 2.73 × 10-10
b. 6.60 × 10-5
c. 1.32 × 10-4
d. 1.51 × 104
e. 3.66 × 109
25. For the reaction , 2A ⇌ 3B , Kc = 1.37. If the concentrations of A and B are equal, what is
the value of that concentration?
a. 0.685 M
b. 0.822 M
c. 1.17 M
d. 1.37 M
e. 1.88 M
26. Consider the equilibrium system
C(s) + CO2(g) ⇌ 2CO(g) .
If more C(s) is added, the equilibrium will ____; if CO is removed the equilibrium will ____.
a. shift to the left; shift to the left
b. shift to the right; shift to the right
c. shift to the right; shift to the left
d. be unchanged; shift to the left
e. be unchanged; shift to the right
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27. Determine the chloride ion concentration in a solution containing 50.0 g MgCl2 dissolved in
1500 mL of solution.
a. 0.350 M
b. 0.700 M
c. 1.40 M
d. 3.17 M
e. 6.34 M
28. In the following equation, which is the conjugate base of CH3COOH?
CH3COOH + H2O ⇌ CH3COO- + H3O+
a. CH3COOb. H3O+
c. H2O
d. CH3COOH
e. none of the above
29. In the following equation, which species plays the role of acid to CH3NH2 ?
CH3NH2 + H2O ⇌ CH3NH3+ + OHa. CH3NH3+
b. H3O+
c. H2O
d. OHe. none of the above
30. In a 1.2 M solution of KOH, a strong base, [H3O+] = _____, and [OH-] = _____.
a. 1.0 × 10-7 M; 1.0 x10-7 M
b. 8.3 × 10-15 M; 1.0 x10-14 M
c. 8.3 × 10-15 M; 1.2 M
d. 1.2 M; 12.8 M
e. 12.8 M; 1.2 M
31. Calculate the pH of a solution where [OH-] = 4.6 × 10-4. Is this solution acidic or basic?
a. 3.34; acidic
b. 3.34; basic
c. 9.40; basic
d. 10.66; acidic
e. 10.66; basic
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32. The pH of a 0.50 M solution of the weak acid HA is 4.76. The value of Ka is
a. 6.0 × 10-10
b. 1.7 × 10-5
c. 3.5 × 10-5
d. 7.6 × 10-4
e. 9.24
33. The Henderson-Hasselbach equation, often used for selecting buffers, is:
[ A− ]
pH = pK a + log
; If you are making a buffer with a weak acid and its salt, and the
[ HA]
weak acid has a pKa of 6.0, what should your ratio [A-]/[HA] be to obtain a buffer of pH
5.0?
a. 100
b. 10
c. 1
d. 0.1
e. none of the above
34. Which acid, in combination with its conjugate base, would be the best choice to make a
buffer of pH = 4.20?
a. acetic acid (Ka = 1.8 × 10-5)
b. benzoic acid (Ka = 6.3 x 10-5)
c. formic acid (Ka = 1.8 × 10-4)
d. hydrofluoric (Ka = 7.2 × 10-4)
e. nitrous acid (Ka = 4.5 × 10-4)
35. Calculate the value of ΔS° for the reaction shown:
N2(g) + 3 H2(g) ⇌ 2 NH3(g)
At 25°C the values of entropy in J K-1 mol-1 are :
Nitrogen, 191.61
Hydrogen, 130.68
Ammonia, 192.77.
a. -198.11 J/K
b. -259.03 J/K
c. -390.88 J/K
d. -393.20 J/K
e. -969.19 J/K
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36. Use the data given to calculate the value of ΔG°rxn for the reaction at 25°C.
2 C(graphite) + H2(g) → C2H2(g)
S° (J K-1 mol-1)
ΔH°f (kJ/mol)
C(graphite)
5.74
0
H2(g)
130.68
0
C2H2(g)
201.0
-226.8
a. -291.4 kJ
b. -244.3 kJ
c. -226.8 kJ
d.-207.6 kJ
e. -64.6 kJ
37. A reaction is product-favored when
a. Ko < 1 and ΔGo > 0
b. Ko > 1 and ΔGo < 0
c. Ko = 1 and ΔGo = 0
d. Ko = 0 and ΔGo = 0
e. Ko < 1 and ΔGo = 0
38. The value of the equilibrium constant for a reaction is 2.65 × 10-6 at a temperature of 298 K.
Calculate the value of ΔG°rxn at this temperature.
a. +31.8 kJ
b. +34.0 kJ
c. +14.8 kJ
d. +335 kJ
e. -14.8 kJ
39. Calculate the equilibrium constant, K, for the reaction shown at 25oC if ΔG° = -32.8 kJ for
the reaction:
N2(g) + 3H2(g) ⇌ 2NH3(g)
a. 6.3 x 1010
b. 6.3 x 10-10
c. 5.6 x 105
d. -5.6 x 105
e. -12.0
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40. The value of Eocell for an aluminum-nickel electrochemical cell is +1.41 V at 25°C.
Calculate the value of ΔG° for this cell under standard conditions.
a. -816 kJ
b. -680 kJ
c. -272 kJ
d. +403 kJ
e. +680 kJ
41. The value of Eocell for an aluminum-nickel electrochemical cell is +1.41 V at 25°C.
The value of K° for this cell under standard conditions is
a. <<0.01
b. ≈ 0.01
c. ≈ 1
d. ≈ 100
e. >>100
42. Consider the following balanced redox equation:
3 Zn(s) + 2 NO3-(aq) + 8 H+(aq) → 3 Zn2+(aq) + 2 NO(g) + 4 H2O (l)
What species is oxidized; what species is reduced; and how many electrons are transferred?
a. H2O, H+, eight
b. Zn, NO, three
c. Zn, Zn2+, three
d. Zn, NO3-, six
e. NO, NO3-, two.
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