CH186Practice Final Exam

This is an example final containing questions from previous final exams and quizzes. Because content varies from semester to semester, it may contain questions from chapters not covered in any given semester. Just ignore those questions.

Time limit for the final is typically 1 hour 50 minutes.

Useful Constants and InformationKw = 1.0 x 10-14

gas constant, R = 8.31451 J/(molK)1 F = 96500 CRT/F = 0.0257 V (at 25C)2.303RT/F = 0.0592 V (at 25C)Avogadro’s number (NA) = 6.022137 x 1023/molmass of proton = 1.007276 amumass of neutron = 1.008664 amumass of electron = 5.485799 x 10-4 amuspeed of light, C = 3.0 x 108 m/s1 amu = 1.660540 x 10-24 g1 J = 1 kgm2/s2

1 eV = 1.602 x 10-19 J1 Mev = 106 eV

Multiple Choice

1. Which of the following organic compounds is a carboxylic acid?

a.

b.

c.

d.

e.

2. Which of the following organic compounds is an alkyne?

a.

b.

c.

d.

e.

3. A straight chain alkane has 6 carbon atoms. Its molecular formula is

a. C6H14 d. C6H10

b. C6H12 e. C6H8

c. C6H6

4. A solution has a pOH value of 5.08. The [H3O+] concentration for this solution is:

a. 1.2 x 10-9 M d. 0.012 Mb. 5.4 x 10-10 M e. 8.92 Mc. 8.3 x 10-6 M

5. The acid 4-aminobenzoic acid, HB, has Ka = 1.2 x 10-5. The pH of a 0.23 M solution of HB in water is approximately:

a. 0.64 d. 5.56b. 2.78 e. 3.20c. 4.92

6. What is the percent ionization of a 0.50 M aqueous solution of the weak base ammonia, NH3, if Kb = 1.8 x 10-5?

a. 0.0030 % d. 0.60 %b. 1.0 % e. none of these is correctc. 0.10 %

7. Calculate the pH of a nitric acid (HNO3) solution with a concentration of 3.1 x 10-3 M.

a. 11.49 d. 3.10b. 2.22 e. 2.51c. 2.87

8. What is the pH of a buffer solution which contains 0.25 M acetic acid, CH3COOH (Ka = 1.8 x 10-5), and 0.50 M sodium acetate, CH3COONa (Kb = 5.6 x 10-10)?

a. 5.05 d. 4.44b. 8.95 e. 9.55c. 4.74

9. According to the Bronsted-Lowry concept, the acid in an acid-base reaction is defined as the substance that

a. donates an electron pairb. accepts a protonc. donates a protond. produces OH- ions in aqueous solutione. produces H+ ions in aqueous solution

10. What is the pH of the solution that results when 20.0 mL of 0.100 M KOH(aq) are mixed with 40.0 mL of 0.050 M HCl(aq).

KOH + HCl KCl + H2O

a. 1.30b. 1.48c. 13.00d. 11.23e. 7.00

11. Which of the following solutions would have the lowest pH assuming each solution has the exact same concentration?

a. HFb. NaOHc. NH3

d. HClO4

e. The pH would be the same in each case since the concentrations are all the same.

12. A negative sign for G indicates that

a. the reaction is nonspontaneous.b. the reaction is exothermic.c. the reaction is spontaneous.d. the reaction occurs rapidly.e. the entropy of the system increases.

13. The second law of thermodynamics states that:

a. the entropy of the universe increases during a spontaneous change.b. the total energy of the universe is constant.c. the energy of the universe increases during a spontaneous change.d. the entropy of a perfect crystal at 0 K is zero.e. none of these is correct

14. For a particular chemical reaction, Hrxn is -55.8 kJ and Srxn is -100.0 J/K. If this reaction is carried out at 200C, which of the following is true?

a. G = -35.8 kJ; reaction is spontaneousb. G = -35.8 kJ; reaction is nonspontaneousc. G = -8.5 kJ; reaction is nonspontaneousd. G = -8.5 kJ; reaction is spontaneouse. none of the these is correct

15. Consider the chemical equation for the reduction of PbO:

2PbO(s) + C(s) 2Pb(s) + CO2(g)

Calculate Srxn for this reaction given the following standard entropies at 25C.

S (J/K mol) PbO(s) 69.45C(s) 5.7Pb(s) 64.89CO2(g) 213.6

a. +488.0 J/Kb. +353.6 J/Kc. -203.3 J/Kd. +203.3 J/Ke. +198.8 J/K

16. At 25C, Ka for the ionization of aspirin (C9H8O4) is 3.0 x 10-4. Calculate G in kJ for the ionization of aspirin in water.

C9H8O4 + H2O H3O+ + C9H7O4-

a. -2.48 kJb. 8.7 kJc. -20.1 kJd. -8.7 kJe. none of these is correct

17. Entropy is a measure of

a. the rate of a reaction.b. the heat of a reaction.c. the free energy change of a reaction.d. molecular randomness.e. none of these is correct

18. Which of the following about the entropy S of a substance is correct?

a. Sliquid < Ssolid < Sgas

b. Ssolid < Sgas < Sliquid c. Ssolid = Sliquid = Sgas

d. Ssolid < Sliquid = Sgas

e. Ssolid < Sliquid < Sgas

19. The cathode in a voltaic cell is

a. the electrode at which oxidation occurs.b. the electrode at which reduction occurs.c. always a standard hydrogen electrode.d. the electrode towards which anions flow through the solution of the cell.e. none of these is correct

20. Calculate the cell potential, Ecell, for the galvanic cell that utilizes the reaction below when [Cr3+] = 0.10 M and [Ag+] = 0.00020 M.

Cr(s) + 3Ag+(aq) 3Ag(s) + Cr3+(aq)

a. 1.41 Vb. 1.53 Vc. 1.33 Vd. 1.74 Ve. none of these is correct

21. A steel pipe can be protected from corrosion by attaching the pipe to a piece of magnesium because

a. magnesium forms a tight oxide coating.b. magnesium and steel form a corrosion resistant alloy.c. magnesium is an inert metal.d. magnesium is more easily oxidized than iron.e. magnesium is a weaker reducing agent than iron.

22. What is the correct shorthand notation for the voltaic cell that utilizes the reaction below.Fe(s) + Cu2+(aq) Fe2+(aq) + Cu(s)

a. Fe(s)/Fe2+(aq)//Cu2+(aq)/Cu(s)b. Cu(s)/Cu2+(aq)//Fe2+(aq)/Fe(s)c. Fe(s)/Cu2+(aq)//Fe2+(aq)/Cu(s)d. Pt(s)/Fe2+(aq)//Cu2+(aq)/Pt(s)e. Fe2+(aq)/Fe(s)//Cu(s)/Cu2+(aq)

23. Calculate E for the Galvanic cell that uses the reaction below.

Ni(s) + 2Ag+(aq) Ni2+(aq) + 2Ag(s)a. 1.37b. 1.83c. 0.57d. 1.03 Ve. none of these is correct

24. Which of the statements below about the following redox reaction is correct?

3Co(s) + 2NO3-(aq) + 8H+(aq) 2NO(g) + 3Co2+(aq) + 4H2O(l)

a. Co is the oxidizing agent and NO3- is the reducing agent.

b. Co is the reducing agent and NO3- is the oxidizing agent.

c. Co is the reducing agent and H+ is the oxidizing agent.d. H+ is the reducing agent and NO3

- is the oxidizing agent.e. none of these is correct

25. How many electrons are transferred in the overall redox reaction below?

3Ni(s) + Cr2O72- + 14H+ 3Ni2+ + 2Cr3+(aq) + 7H2O(l)

a. 2b. 6c. 3d. 8e. 12

26. The molar solubility of strontium fluoride (SrF2) is 8.0 x 10-4 M at 25C. Calculate the solubility product (Ksp) for SrF2?

a. 5.1 x 10-10

b. 2.6 x 10-6

c. 6.4 x 10-7

d. 2.0 x 10-9

e. none of these is correct

27. Which of the following insoluble salts has the greatest molar solubility?

a. Ag2SO4, Ksp = 1.4 x 10-5

b. CaF2, Ksp = 4.0 x 10-11

c. BaF2, Ksp = 1.7 x 10-6

d. PbF2, Ksp = 4.1 x 10-8

e. These salts are all equally soluble in water since they all have the same relationship between Ksp and molar solubility.

28. Calculate the molar solubility of insoluble BaSO4 (Ksp = 1.0 x 10-10) in a solution that contains 0.020 M of the soluble salt Na2SO4.

a. 1.0 x 10-5

b. 2.0 x 10-12

c. 7.1 x 10-5

d. 5.0 x 10-9

e. 1.4 x 10-6

29. If the value of Ksp for PbF2 is 4.0 x 10-8, what would happen when 100.0 mL of a 0.060 M Pb2+ solution and 100.0 mL of a 0.020 M F- solution are mixed?

a. nothing, Qsp = Ksp

b. nothing, Qsp < Ksp

c. precipitation of PbF2, Qsp > Ksp

d. no prediction can be made because insufficient information is provided

30. Consider the molar solubility (s) of silver sulfate, Ag2SO4. Which one of the following relationships is correct?

a. [SO42-] = s/2

b. [Ag+] = sc. [SO4

2-] = 2[Ag+]d. [Ag+]2 = se. [Ag+] = 2s

31. What is [OH-] in a saturated solution of Mg(OH)2? The Ksp for Mg(OH)2 = 5.6 x 10-12.

a. 2.2 x 10-4 M b. 1.4 x 10-4 Mc. 3.6 x 10-4 Md. 1.1 x 10-4 Me. none of these is correct

32. What is the correct solubility product expression for Zn3(PO4)2?

a. Ksp = [Zn32+][PO4

3-]2

b. Ksp = [Zn2+]3[(PO43-)2]

c. Ksp = [Zn2+]3[PO43-]2

d. Ksp = 3[Zn2+]2[PO43-]

e. Ksp = [Zn2+]2[PO43-]3

33. According to crystal field theory, how many unpaired d electrons are present in the octahedral complex ion Fe(CN)6

3-? The CN- ion is a strong field ligand.

a. 2b. 0c. 1d. 5e. 3

34. The electron configuration of the Co3+ ion is:

a. [Ar]4s23d4 d. [Ar]4s23d10

b. [Ar]3d5 e. [Ar]4s13d5

c. [Ar]3d6

35. Which one of the following octahedral complexes exhibits optical isomerism, i.e. has enantiomers? (en represents the bidentate ligand ethylenediamine.)

a. [Co(NH3)5(H2O)]3+

b. [Cr(NH3)6]3+

c. [Cr(NH3)4Cl2]+

d. [Fe(en)(NH3)4]3+

e. [Ni(en)2(NH3)2]2+

36. The correct IUPAC name for [Co(en)2Br2]Br is:

a. cobalt(III)bis(ethylenediamine) bromideb. tribromobis(ethylenediamine)cobaltate(III)c. dibromobis(ethylenediamine)cobaltate(III) bromided. dibromobis(ethylenediamine)cobalt(III) bromidee. bis(ethylenediamine)cobalt(III) tribromide

37. Considering only electron configurations, which of the following octahedral complexes would be expected to be colorless?

a. Fe(H2O)63+

b. Sc(H2O)63+

c. Ni(H2O)63+

d. Cr(H2O)63+

e. Mn(H2O)63+

38. For an octahedral transition metal complex, which metal d orbitals have lobes that are directed towards the ligands?

a. dxy, dx2-y2b. dxy, dyz, dxz

c. dz2, dx2-y2d. dz2, dxz, dyz e. none of these is correct

39. What is the coordination number of Fe in K3[Fe(C2O4)3]? (C2O42- is the bidentate ligand

oxalate ion.)

a. 2b. 3c. 4d. 5e. 6

40. The number of neutrons in Fe is

a. 26b. 29c. 55d. 81e. none of these is correct

41. What is the product of beta decay of I?

a. Sbb. Tec. Csd. Xee. I

42. Iodine-131, which is used to treat thyroid cancer, has a half-life of 8.05 days. How much time is required for 93% of the isotope to decay?

a. 0.84 daysb. 11 daysc. 27 daysd. 31 dayse. 38 days

43. Calculate the binding energy in kJ/mol for the C nucleus (11.99671 amu).

a. 1.10 x 1015 kJ/molb. 8.90 x 109 kJ/molc. 5.54 x 1012 kJ/mold. 6.95 x 1011 kJ/mole. none of these is correct

44. What percentage of a radioactive substance remains after 6 half-lives have elapsed?

a. 1.56 %b. 16.7 %c. 12.5 %d. 0.78 %e. 6.25 %

45. Gamma radiation can be described as:

a. a helium nucleusb. a negatively charged free electronc. high energy electromagnetic radiationd. a positively charged free electrone. a high energy neutron

46. “Isotopes” are atoms with the same number of _____ but different number of _____.

a. protons, neutrons b. neutrons, protonsc. protons, electronsd. electrons, protonse. neutrons, electrons

47. The conversion of reactant A to product B, A(g) B(g), is first order in A. The rate constant for the reaction is 8.77 x 10-5 s-1 at 400 K. Calculate the half life of the reaction when the initial [A] is 0.020 M.

a. 158 s d. 6.08 x 10-5 sb. 7.90 x 103 s e. None of the abovec. 3.95 x 105 s

48. The mechanism for the formation of product X is:

A + B C + D (slow)B + D X (fast)

The intermediate in the reaction is _____.

a. A b. B c. C d. D e. X

49. The mechanism for a reaction is considered to occur in two steps (shown below). The rate expression for the rate of the overall reaction is rate = _____.

A + B C + D (slow)A + C E + F (fast)

a. k[A][B] d. k[A][C]b. k[A][B][C] e. k[A]2[B][C]c. k[A]2[B]

50. Of the following, _____ will lower the activation energy for a reaction.

a. removing products as the reaction proceedsb. increasing the concentrations of reactantsc. raising the temperature of the reactiond. increasing the pressuree. adding a catalyst for the reaction

51. Which of the following best explains why increasing the concentrations of reactants increases the rate of the reaction?

a. The rate constant increases.b. The kinetic energy of the reactant molecules increases.c. The frequency of molecular collisions increases.d. The fraction of molecules that has enough energy to react increases.e. The activation energy is increased.

52. Consider the following endothermic reaction:

SO2Cl2(g) SO2(g) + Cl2(g)

The concentration of SO2Cl2(g) at equilibrium will be increased by _____.

a. removing Cl2

b. adding a catalystc. removing SO2

d. increasing the volume of the reaction vessele. decreasing the temperature

53. The equilibrium constant for the gas phase reaction below is Keq = 230 at 300C. At equilibrium, _____.

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

a. reactants predominateb. products predominatec. roughly equal amounts of products and reactants are presentd. only products are presente. only reactants are present

54. At equilibrium, _____.

a. all chemical reactions have ceasedb. the value of the equilibrium constant is 1c. the limiting reagent has been consumedd. the rate constants of the forward and reverse reactions are equale. the rates of the forward and reverse reactions are equal

55. The equilibrium constant expression for the reaction

Ti(s) + 2Cl2(g) TiCl4(l)

is given by

a. [TiCl4]/[Ti][Cl2]2 d. 1/[Cl2]2

b. [TiCl4]/[Cl2]2 e. [Ti][Cl2]2/[TiCl4]c. [TiCl4]/[Ti][Cl2]

56. Acetic acid is a weak acid that dissociates according to the following reaction:

CH3COOH(aq) CH3COO-(aq) + H+(aq)

At equilibrium at 25C, a 0.100 M solution of acetic acid has the following concentrations: [CH3COOH] = 0.0990 M, [CH3COO-] = 0.00133 M, [H+] = 0.00133 M. What is the equilibrium constant, Keq, for the ionization of acetic acid?

a. 0.100 b. 5.60 x 104 c. 1.79 x 10-5 d. 0.0134 e. 1.77 x 10-6

Standard Reduction Potentials in Aqueous Solution (25C)

Reduction Half-Reaction E(V)F2(g) + 2e- 2F-(aq) 2.87Co3+(aq) + e- Co2+(aq) 1.82Ce4+(aq) + e- Ce3+(aq) 1.70Mn3+(aq) + e- Mn2+(aq) 1.54MnO4

-(aq) + 8H+(aq) + 5e- Mn2+(aq) + 4H2O(l) 1.51Au3+(aq) + 3e- Au(s) 1.50Cl2(g) + 2 e- 2Cl-(aq) 1.36O2(g) + 4H+ + 4e- 2H2O(l) 1.23NO3

-(aq) + 4H+(aq) + 3e- NO(g) + 2H2O(l) 0.96Hg2+(aq) + 2e- Hg(l) 0.86Ag+(aq) + e- Ag(s) 0.80Fe3+(aq) + e- Fe2+(aq) 0.77MnO4

-(aq) + e- MnO42-(aq) 0.56

O2(g) + 2H2O(l) + 4e- 4OH-(aq) 0.40Cu2+(aq) + 2e- Cu(s) 0.34Bi3+(aq) + 3e- Bi(s) 0.31Sn4+(aq) + 2e- Sn2+(aq) 0.152H+(aq) + 2e- H2(g) 0.00Pb2+(aq) + 2e- Pb(s) -0.13Sn2+(aq) + 2e- Sn(s) -0.14Mo3+(aq) + 3e- Mo(s) -0.20Ni2+(aq) + 2e- Ni(s) -0.23Co2+(aq) + 2e- Co(s) -0.28Cd2+(aq) + 2e- Cd(s) -0.40Cr3+(aq) + e- Cr2+(aq) -0.41Fe2+(aq) + 2e- Fe(s) -0.44Ga3+(aq) + 3e- Ga(s) -0.55Cr3+(aq) + 3e- Cr(s) -0.73Zn2+(aq) + 2e- Zn(s) -0.76Mn2+(aq) + 2e- Mn(s) -1.18Ti2+(aq) + 2e- Ti(s) -1.63Al3+(aq) + 3e- Al(s) -1.66Sc3+(aq) + 3e- Sc(s) -2.08Mg2+(aq) + 2e- Mg(s) -2.37Y3+(aq) + 3e- Y(s) -2.37Ca2+(aq) + 2e- Ca(s) -2.76Ba2+(aq) + 2e- Ba(s) -2.90Li+(aq) + e- Li(s) -3.04

Periodic Table of the ElementsI II III IV V VI VII VIII

11H

1.008

2He

4.0026

23Li

6.941

4Be

9.0122

5B

10.81

6C

12.011

7N

14.007

8O

15.999

9F

18.998

10Ne

20.179

311Na

22.990

12Mg

24.305

13Al

26.982

14Si

28.086

15P

30.974

16S

32.06

17Cl

35.453

18Ar

39.948

419K

39.098

20Ca

40.078

21Sc

44.956

22Ti

47.88

23V

50.942

24Cr

51.996

25Mn

54.938

26Fe

55.847

27Co

58.933

28Ni

58.69

29Cu

63.546

30Zn

65.38

31Ga

69.72

32Ge

72.59

33As

74.922

34Se

78.96

35Br

79.904

36Kr

83.80

537Rb

85.468

38Sr

87.62

39Y

88.906

40Zr

91.22

41Nb

92.906

42Mo

95.94

43Tc

(98)

44Ru

101.07

45Rh

102.91

46Pd

106.4

47Ag

107.87

48Cd

112.41

49In

114.82

50Sn

118.69

51Sb

121.75

52Te

127.60

53I

126.90

54Xe

131.29

655Cs

132.91

56Ba

137.33

57« La

138.91

72Hf

178.49

73Ta

180.95

74W

183.85

75Re

186.21

76Os

190.2

77Ir

192.22

78Pt

195.08

79Au

196.97

80Hg

200.59

81Tl

204.38

82Pb

207.2

83Bi

208.98

84Po

(209)

85At

(210)

86Rn

(222)

787Fr

(223)

88Ra

226.03

89§ Ac

227.03

104Rf

(261)

105Db

(262)

106Sg

(263)

107Bh

(262)

108Hs

(265)

109Mt

(266)

110Uun(269)

111Uuu(272)

112Uub(277)

« lanthanides58Ce

140.12

59Pr

140.91

60Nd

144.24

61Pm

(145)

62Sm

150.36

63Eu

151.96

64Gd

157.25

65Tb

158.93

66Dy

162.50

67Ho

164.93

68Er

167.26

69Tm

168.93

70Yb

173.04

71Lu

174.97

§ actinides90Th

232.04

91Pa

231.04

92U

238.03

93Np

237.05

94Pu

(244)

95Am

(243)

96Cm

(247)

97Bk

(247)

98Cf

(251)

99Es

(252)

100Fm

(257)

101Md

(258)

102No

(259)

103Lr

(260)

CH186Practice Final Exam

Key1. b 43. b2. e 44. a3. a 45. c4. a 46. a5. b 47. b6. d 48. d7. e 49. a 8. a 50. e9. c 51. c10. e 52. e11. d 53. b12. c 54. e13. a 55. d14. d 56. c15. e16. e17. d18. e19. b20. c21. d22. a23. d24. b25. b26. d27. a28. d29. c30. e31. a32. c33. c34. c35. e36. d37. b38. c39. e40. b41. d42. d