Download Chapters 12 – 20 Practice Problems

Timothy Subrahmanyam
Spring 2016 – Study Union
Study Union 2016
Live Streamed Final Exam Review for
Chemistry II (CHM 2046)
Wednesday, April 27th, 2016
2:30PM – 4:30PM
By Timothy Subrahmanyam
This review is on
sites.google.com/site/ucfstudyunion/
Timothy Subrahmanyam
Spring 2016 – Study Union
Chapter 11: Liquids, Solids, and Intermolecular Forces
1. Choose the substance with the highest boiling point.
A) CH3CH2CH2CH3
B) CCl4
C) CH3OH
D) CH3Cl
E) CF4
Figure 11.1
2. Calculate the mass of water that can be vaporized with 155 kJ of heat at 100 °C? (∆Hvap =
40.7 kJ/mol, Molar Mass of Water = 18.02 g/mol)
A) 12.0 g
B) 35.9 g
C) 36.7 g
D) 68.6 g
E) 88.9 g
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Spring 2016 – Study Union
(Use the diagram above to answer problems 3-4)
3. What is this substance at 30 °C and 1.0 atm?
A) supercritical fluid
B) crystal
C) liquid
D) solid
E) gas
4. What does line segment AD represent?
A) critical point
B) vaporization curve
C) sublimation curve
D) supercritical fluid
E) fusion curve
Figure 11.2
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Spring 2016 – Study Union
5. How much heat in kJ is needed to raise the temperature of a 12.0 g benzene sample from
-10.0 °C to 25.0 °C? (Molar mass of benzene = 78.11 g/mol, Specific Heat of Solid = 1.25 J/g x
°C, Specific Heat of Liquid = 1.70 J/g x °C, Heat of Fusion = 9.8 kJ/mol, Melting Point = 5.5 °C,
Boiling Point = 30.0 °C)
A) 0.5 kJ
B) 2.1 kJ
C) 17.2 kJ
D) 24.4 kJ
E) 60.2 kJ
Chapter 12: Solutions
6. Which one of the following substances is more likely to dissolve in CBr4?
A) CH3CH2CH2OH
B) NaF
C) HBr
D) CF4
E) HF
7. The solubility of carbon dioxide gas as 25 °C and 1 atm is 6.8 x 10-4 mol/L. If the partial
pressure of carbon dioxide gas in air is 0.76 atm, what is the concentration (molarity) of
dissolved carbon dioxide?
A) 1.4 x 10-5 M
B) 2.9 x 10-4 M
C) 4.5 x 10-4 M
D) 5.2 x 10-4 M
E) 7.1 x 10-4 M
8. Calculate the molality of a solution made by dissolving 34.0 g of NH3 in 2.00 x 103 g of
solution. (Molar Mass of NH3 = 17.04 g/mol)
A) 1.02 m NH3
B) 0.53 m NH3
C) 12.43 m NH3
D) 12.53 m NH3
E) 4.65 m NH3
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Spring 2016 – Study Union
Figure 12.1
9. A 1.26 m aqueous solution of compound Y had a boiling point of 101.3 °C. Which one of the
following could be compound Y? The boiling point elevation constant for water is 0.51 °C/m.
A) Na3PO4
B) CaBr2
C) CH3CH2CH2OH
D) NaCl
E) C6H12O6
10. What is the molar mass of lysozyme if 0.0750 g per 100.0 mL gives an osmotic pressure of
1.32 x 10-3 atm at 25 °C?
A) 0.11 x 103 g/mol
B) 0.58 x 103 g/mol
C) 1.13 x 103 g/mol
D) 1.24 x 104 g/mol
E) 1.39 x 104 g/mol
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Spring 2016 – Study Union
Figure 12.2
Chapter 13: Chemical Kinetics
11. For the reaction given, the NOBr changes from 1.000 M to 0.868 M in the first 10 seconds.
Calculate the average rate in the first 10 seconds.
2 NOBr(g)  2 NO(g) + Br2(l)
A) 0.0132 M/s
B) 0.0066 M/s
C) 0.0396 M/s
D) 0.119 M/s
E) 0.00147 M/s
12. Determine the rate law for the reaction 2NO2(g) + 2CO(g)  2NO(g) + 2CO2(g) given the data
below.
A)
B)
C)
D)
E)
Rate = k[NO2]2[CO]2
Rate = k[NO2]2
Rate = k[NO][CO2]
Rate = k[NO2]2[CO]2[NO]2[CO2]2
Rate = k[NO2][CO]
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13. The reaction below is first order with a rate constant of 2.90 x 10-4s-1 at a given set of
conditions. Find the [SO2Cl2] at 865 s when [SO2Cl2]initial = 0.0225 M.
SO2Cl2(g)  SO2(g) + Cl2(g)
A) 4.04 M
B) 0.251 M
C) 0.0225 M
D) 0.0290 M
E) 0.0175 M
14. The rate law for a reaction is
Rate = k[A]2[B]
Which one of the following statements is false?
A)
B)
C)
D)
E)
The reaction is first order in B.
K is the reaction rate constant.
The reaction is second order in A.
If [A] is doubled, the reaction rate will increase by a factor of 4.
The reaction is second order overall.
15. Determine the overall reaction, the rate determining step, the rate law, and identify all
catalysts and intermediates of the following mechanism.
1. 2HQ2R2 + 2R− ↔ 2Q2R2− + 2HR
Slow
−
−
2. 2Q2R2 ↔ 2Q2R + 2R
Fast
Figure 13.1
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Chapter 14: Chemical Equilibrium
16. The Keq for the equilibrium below is 0.002 at 450.0 °C. [T2 Q16]
CO2(g) + ½ O2(g) ↔ CO3(g)
What is the value of Keq at this temperature for the following reaction and does it favor
reactants or products?
2 CO3(g) ↔ 2 CO2(g) + O2(g)
A)
B)
C)
D)
E)
2.50 x 102, products
1.00 x 103, products
1.00 x 103, reactants
2.50 x 105, products
2.50 x 105, reactants
17. For the reaction N2O4(g) ↔ 2 NO2(g) the value of Kc = 1.07 x 10-5. If the initial concentrations
of N2O4 is 0.0125 M, what will be the equilibrium concentration of [NO2]?
A) 3.66 x 10-4 M
B) 4.75 x 10-4 M
C) 1.83 x 10-4 M
D) 0.0123 M
E) 0.0248 M
18. What is the equilibrium constant expression for the reaction?
Cr(s) + 2 Br2(g) ↔ CrBr4(l)
−2
A) [𝐵𝑟2 (𝑔)]
B)
C)
D)
E)
[𝐶𝑟𝐵𝑟4 (𝑙)]
[𝐵𝑟2 (𝑔)]2
[𝐶𝑟(𝑠)][𝐵𝑟2 (𝑔)]2
𝐶𝑟𝐵𝑟4 (𝑙)
[𝐶𝑟𝐵𝑟4(𝑙)]
[𝐶𝑟(𝑠)][𝐵𝑟2 (𝑔)]
[𝐶𝑟𝐵𝑟4(𝑙)]
[𝐶𝑟(𝑠)][𝐵𝑟2 (𝑔)]2
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19. The reaction below with H° = −238 kJ is at equilibrium. Which of the following statements is
false?
2 CH4(g) + 4 O2(g)  2 CO2(g) + 4 H2O(l)
A) Adding CH4(g) will shift equilibrium to the right.
B) Cooling the container will shift equilibrium to the right.
C) Adding a catalyst to the mixture has no effect.
D) Adding helium to the container has no effect
E) Removing O2(g) from the container shifts equilibrium to the left.
F) Adding H2O(l) shifts equilibrium to the left.
20. The reaction below with H° = 83 kJ is at equilibrium. Which of the following statements is
false?
2 SO2(g) + O2(g)  2 SO3(g)
A)
B)
C)
D)
E)
Compressing the gases shifts equilibrium to the right.
Heating the mixture shifts equilibrium to the right.
Cooling the mixture shifts equilibrium to the left.
Doubling the volume of the container shifts equilibrium to the right.
Adding SO3(g) shifts equilibrium to the left.
Chapter 15: Acids and Bases
21. An aqueous solution of which of the following will form acidic solutions?
SrCl2
A)
B)
C)
D)
E)
AlBr3
CH3NH3NO3
NaCHO2
NH4F
SrCl2, AlBr3
SrCl2 only
AlBr3, CH3NH3NO3, NH4F
NaCHO2 only
SrCl2, AlBr3, NaCHO2
22. Identify the Brønsted–Lowry acid, base, conjugate acid, and conjugate base in the following
reaction.
HSO4−(aq) + HCO3−(aq)  SO42−(aq) + H2CO3(aq)
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Spring 2016 – Study Union
23. What is the conjugate base of the H2PO41-?
A) PO43B) HPO42C) H2PO41D) H3PO4
E) H4PO41+
24. Find the pH of 0.200 M HNO2(aq) solution at 25 °C with a Ka for HNO2 = 4.6 x 10-4.
A) 1.03
B) 2.02
C) 7.00
D) 8.23
E) 9.27
Figure 15.1
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Chapter 16: Aqueous Ionic Equilibrium
25. What is the pH of a buffer that is 0.050 M HC7H5O2 and 0.150 M NaC7H5O2?
Ka for HC7H5O2 = 6.5 x 10−5
A)
B)
C)
D)
E)
4.66
4.19
5.67
8.94
11.5
26. What is the pH of a buffer that has 0.140 moles HF (pKa = 3.15) and 0.071 moles KF in 1.00 L
of solution when 0.020 moles of HCl is added?
A) 1.20
B) 2.65
C) 3.00
D) 3.15
E) 4.16
27. Which of the solutions below has the greatest buffering capacity?
A) 0.887 M NH4Cl and 0.234 M NH3
B) 0.812 M NH4Cl and 0.798 M NH3
C) 0.543 M NH4Cl and 0.492 M NH3
D) 0.194 M NH4Cl and 0.186 M NH3
E) 0.634 M NH4Cl and 0.267 M NH3
28. Calculate the pH of the solution that results when 100.0 mL of 0.15 M NaOH is added to
50.0 mL of 0.25 M HNO3.
A) 1.17
B) 5.88
C) 1.77
D) 1.83
E) 12.23
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29. Calculate the molar solubility of CaF2 in 0.100 M NaF at 25 C. Ksp of CaF2 = 1.46 x 10-10
A) 4.36 x 10-8
B) 1.46 x 10-8
C) 0.100
D) 1.46 x 10-10
E) 5.34 x 10-10
Chapter 17: Free Energy and Thermodynamics
30. Calculate the entropy change of the surroundings at 25C for the reaction below.
C3H8(g) + 5 O2(g)  3 CO2(g) + 4 H2O(g) ∆Hrxn = −2044 kJ
A) 1.30 kJ/K
B) 15.5 kJ/K
C) 6.86 kJ/K
D) 10.4 kJ/K
E) 20.5 kJ/K
31. The reaction CCl4(g)  C(s, graphite) + 2 Cl2(g) has ∆H = +95.7 kJ and ∆S = +142.2 J/K at 25 °C.
Calculate ∆G and determine if it is spontaneous.
A) 5.33 x 104 J, spontaneous
B) 5.33 x 104 J, nonspontaneous
C) -4.23 x 104 J, spontaneous
D) -4.23 x 104 J, nonspontaneous
E) 1.38 x 105 J, spontaneous
32. Determine the free energy change in the following reaction at 298 K.
2 H2O(g) + O2(g)  2 H2O2(g)
A) -333.6 kJ
B) -587.0 kJ
C) -668.4 kJ
D) 246.0 kJ
E) 123.6 kJ
Substance
∆G ,
kJ/mol
H2O2(g)
−105.6
O2(g)
0
H2O(g)
−228.6
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33. Determine the free energy change in the following reaction at 298 K
2 H2O(g) + O2(g)  2 H2O2(g)
Substance
A) 246.0 kJ
B) -668.4 kJ
H2 (g) + O2(g)  H2O2(g)
C) -562.8 kJ
D) -211.2 kJ
2 H2 (g) + O2(g)  2 H2O(g)
E) 667.2 kJ
Chapter 18: Electrochemistry
34. Balance the following equation in acidic solution and determine which element was
oxidized and reduced, and determine the oxidizing and reducing agent.
I– + CrO42− → Cr3+ + I2
35. Which of the following set of values are characteristic of a spontaneous reaction?
A) ∆G° > 0, E° > 0, K > 1
B) ∆G° < 0, E° < 0, K < 1
C) ∆G° < 0, E° < 0, K > 1
D) ∆G° > 0, E° > 0, K < 1
E) ∆G° < 0, E° > 0, K > 1
∆G , kJ/mol
−105.6
−457.2
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Spring 2016 – Study Union
36. Calculate the E°cell for the following for the overall reaction at 25 °C.
IO3–(aq) + 6 H+(aq) + 5 I−(aq) → 3 I2(s) + 3 H2O(l)
A)
B)
C)
D)
E)
2 I−(s)  I2(aq) + 2 e−
E°red = 0.54 v
IO3−(aq) + 6 H+(aq) + 5 e−  ½ I2(s) + 3 H2O(l)
E°red = 1.20 v
0.66
0.648
1.74
-1.74
-0.648
37. Calculate the mass of Au that can be plated in 25 min using 5.5 A for the half-reaction
below.
Au3+(aq) + 3 e− → Au(s)
(MMAu = 196.97 g/mol)
A) 0.21 g Au
B) 0.67 g Au
C) 5.6 g Au
D) 6.4 g Au
E) 8.1 g Au
38. Which of the following statements is false?
A) Anode loses weight in electrolytic cell.
B) Cathode is connected to the negative end of battery in an electrolytic cell.
C) Anions are attracted to the anode.
D) Electrons flow from cathode to anode.
E) Reduction occurs at the cathode.
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Chapter 19: Radioactivity and Nuclear Chemistry
39. Which mode of radioactive decay produces the change
from U to Th?
A) Electron Capture
B) Beta decay
C) Alpha decay
D) Positron Emission
E) Gamma Decay
Extra Questions:
40. Determine the pH at 25 °C of a solution that is a mixture of 0.045 M HCl and 0.15 M HF.
(Chap 15)
A) 1.50
B) 1.23
C) 1.35
D) 4.56
E) 5.83
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41. Calculate the pH at 25 °C of a 0.0015 M Sr(OH)2 solution. (Chap 15)
A) 7.01
B) 7.46
C) 8.90
D) 11.48
E) 13.87
42. Which of the following materials can be used to oxidize Cu
without oxidizing Ag? (Chap 18)
A) F−
B) I−
C) I2
D) Cr3+
E) Mg2+
Reduction Half-Reaction
F2(g) + 2e− 2 F−(aq)
IO3−(aq) + 6 H++ 5e− I2(s) + 3H2O(l)
Ag+(aq) + 1e− Ag(s)
I2(s) + 2e− 2 I−(aq)
Cu2+(aq) + 2e− Cu(s)
43. Which of the following metals will dissolve in HC2H3O2(aq)?
(Chap 18)
A)
B)
C)
A)
B)
Au, Ag
Ag, Cr
Cu, H2, Ag
Cu only
Fe, Cr
Reduction Half-Reaction
Cr3+(aq) + 1e− Cr2+(aq)
Mg2+(aq) + 2e− Mg(s)
Au3+(aq) + 3e− Au(s)
Ag+(aq) + 1e− Ag(s)
Cu2+(aq) + 2e− Cu(s)
2H+(aq) + 2e− H2(g)
Fe3+(aq) + 3e− Fe(s)
Cr3+(aq) + 3e− Cr(s)
Mg2+(aq) + 2e− Mg(s)
44. Decide whether each of
the following will be
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Spring 2016 – Study Union
spontaneous as written or in the reverse direction.
(Chap 18)
Reduction Half-Reaction
F2(g) + 2e− 2 F−(aq)
F2(g) + 2 I−(aq)  I2(s) + 2 F−(aq)
IO3−(aq) + 6 H++ 5e− I2(s) + 3H2O(l)
Mg(s) + 2
Ag+(aq)

Mg2+(aq)
+ 2 Ag(s)
Ag+(aq) + 1e− Ag(s)
Cu2+(aq) + 2 I−(aq)  I2(s) + Cu(s)
Cu2+(aq) + 2 Cr2+(aq)  Cu(s) + 2 Cr3+(aq)
I2(s) + 2e− 2 I−(aq)
Cu2+(aq) + 2e− Cu(s)
Cr3+(aq) + 1e− Cr2+(aq)
Mg2+(aq) + 2e− Mg(s)
45. If you have a 1.35 mg sample of Pu–236, calculate the mass that will remain after 5.00
years. Half-life of Pu–236 is 2.86 years. (Chap 19)
A) 0.242 mg
B) 0.402 mg
C) 0.693 mg
D) 0.754 mg
E) 1.36 mg
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Spring 2016 – Study Union
Answers to Problems:
1. C
2. D
3. C
4. E
5. B
6. D
7. D
8. A
9. D
10. E
11. B
12. B
13. E
14. E
15. Overall: 2HQ2R2 ↔ 2Q2R +
2HR
Slow is RDS
Rate = k[HQ2R2]2[2R-]2
Catalyst: RIntermediate: Q2R216. D
17. A
18. A
19. F
20. D
21. C
22. Acid: HSO4-, Base: HCO3Conj. Acid: H2CO3, Conj. Base:
SO42-
23. B
24. B
25. A
26. B
27. B
28. E
29. B
30. C
31. B
32. D
33. A
34. Balanced: 6 I- + 16 H+ + 2 CrO42 3 I2 + 2 Cr3+ + 8 H2O
Reduced: Cr Oxidized: IOx. Agent: CrO42- Red. Agent:
I35. E
36. A
37. C
38. D
39. C
40. C
41. D
42. C
43. E
44. Spontaneous
Spontaneous
In reverse
In reverse
45. B