General Chemistry II (CHM 2046) Dr. Lufaso Print Name__________________

Practice Final Exam Fall 2014 /000 pts

Hints and tips for studying for the final exam: • There are more questions on this practice exam than the real final exam

• The actual final exam is not all multiple choice • Study for the final before taking this practice exam

o Work problems on previous exams o Work a problem from each subsection at the end of each chapter

o Study notes taking during lecture

• Take this practice exam without a classmate, your notes, and textbook • Answer key to practice exam (answers only) will be posted on Sunday evening

• Note: There will be questions on the final exam about topics that are not on this practice exam. Do not use this practice exam as your only study aid!

1) Which one of the following should have the lowest boiling point?

A) 3PH

B) 2H S

C) HCl

D) 4SiH

E) 2H O

2) Of the following, __________ has the highest boiling point.

A) 2N

B) 2Br

C) 2H

D) 2Cl

E) 2O

3) The heat of fusion of water is 6.01 kJ/mol. The heat capacity of liquid water is 75.3 J/mol⋅K. The

conversion of 50.0 g of ice at 0.00 °C to liquid water at 22.0 °C requires __________ kJ of heat.

A) 23.8 10×

B) 21.3

C) 17.2

D) 0.469

E) Insufficient data are given.

4) The heating curve shown was generated by measuring the heat flow and temperature for a solid as it was

heated. The slope of the __________ segment corresponds to the heat capacity of the liquid of the

substance.

A) AB

B) BC

C) CD

D) DE

E) EF

5) The heating curve shown was generated by measuring the heat flow and temperature for a solid as it was

heated. The slope of the __________ segment corresponds to the heat capacity of the solid.

A) AB

B) BC

C) CD

D) DE

E) EF

6) What fraction of the volume of each corner atom is actually within the volume of a face-centered cubic

unit cell?

A) 1

B) 1

2

C) 1

4

D) 1

8

E) 1

16

7) CsCl crystallizes in a unit cell that contains the Cs+ ion at the center of a cube that has a Cl- at each

corner. Each unit cell contains __________ Cs+ ions and __________ Cl-, ions, respectively.

A) 1 and 8

B) 2 and 1

C) 1 and 1

D) 2 and 2

E) 2 and 4

8) A solid has a very high melting point, great hardness, and poor electrical conduction. This is a(n)

__________ solid.

A) ionic

B) molecular

C) metallic

D) covalent network

E) metallic and covalent network

9) The solubility of oxygen gas in water at 25 °C and 1.0 atm pressure of oxygen is

0.041 g/L. The solubility of oxygen in water at 3.0 atm and 25 °C is __________ g/L.

A) 0.041

B) 0.014

C) 0.31

D) 0.12

E) 3.0

10) The solubility of Ar in water at 25 °C is 1.6 × 10−3 M when the pressure of the Ar above the solution is

1.0 atm. The solubility of Ar at a pressure of 2.5 atm is __________ M.

A) 1.6 × 103

B) 6.4 × 10−4

C) 4.0 × 10−3

D) 7.5 × 10−2

E) 1.6 × 10−3

11) A solution is prepared by dissolving 23.7 g of CaCl

2in 375 g of water. The density of the resulting

solution is 1.05 g/mL. The concentration of CaCl

2is __________% by mass.

A) 5.94

B) 6.32

C) 0.0632

D) 0.0594

E) 6.24

12) The concentration of urea in a solution prepared by dissolving 16 g of urea in 39 g of H

2O is

__________% by mass. The molar mass of urea is 60.0 g/mol.

A) 29

B) 41

C) 0.29

D) 0.41

E) 0.48

13) The concentration of KBr in a solution prepared by dissolving 2.21 g of KBr in 897 g of water is

__________ molal.

A) 2.46

B) 0.0167

C) 0.0207

D) 2.07 × 10−5

E) 0.0186

14) A solution is prepared by dissolving 15.0 g of NH

3in 250.0 g of water. The density of the resulting

solution is 0.974 g/mL. The mole fraction of NH

3in the solution is __________.

A) 0.0640

B) 0.0597

C) 0.940

D) 0.922

E) 16.8

15) What is the molarity of sodium chloride in solution that is 13.0% by mass sodium chloride and that has

a density of 1.10 g/mL?

A) 143

B) 2.45

C) 2.56

D) 2.23

E) 1.43 × 10−2

16) The reaction below is first order in 2 2[H O ] :

2 2 2 22H O (l) 2H O(l) O (g)→ +

A solution originally at 0.600 M 2 2H O is found to be 0.075 M after 54 min. The half-life for this reaction

is __________ min.

A) 6.8

B) 18

C) 14

D) 28

E) 54

The data in the table below were obtained for the reaction:

A B P+ →

17) The rate law for this reaction is rate = __________.

A) k[A][B]

B) k[P]

C) [ ] [ ]2

k A B

D) [ ] [ ]2 2

k A B

E) [ ]2

k A

18) The reaction

3 3CH N C CH C N− ≡ → − ≡

is a first-order reaction. At 230.3 C° , 4 1k 6.29 10 s− −= × If 3[CH N C]− ≡ is 31.00 10−

× initially,

3[CH N C]− ≡ is __________ after 31.000 10 s×

A) 4 5.33 10−×

B) 42.34 10−×

C) 31.88 10−×

D) 34.27 10−×

E) 61.00 10−×

The reaction A B→ is first order in [A]. Consider the following data.

19) The rate constant for this reaction is __________ 1s− .

A) 26.9 10−×

B) 23.0 10−×

C) 14

D) 0.46

E) 24.0 10×

20) The concentration of A is __________ M after 40.0 s.

A) 21.3 10−×

B) 1.2

C) 0.17

D) 43.5 10−×

E) 0.025

21) The value of K

eq for the equilibrium

2 2H (g) I (g) 2 HI (g)+ ˆ ˆ †‡ ˆ ˆ

is 794 at 25 °C. What is the value of K

eq for the equilibrium below?

2 2 1/ 2H (g) 1/ 2I (g) HI (g) + ˆ ˆ †‡ ˆ ˆ

A) 397

B) 0.035

C) 28

D) 1588

E) 0.0013

22) Consider the following chemical reaction:

2 2H (g) I (g) 2 HI (g)+ ˆ ˆ †‡ ˆ ˆ

At equilibrium in a particular experiment, the concentrations of H

2, I

2 , and HI were 0.15M 0.033M and

0.55M respectively. The value of K

eq for this reaction is __________.

A) 23

B) 111

C) 9.0 × 10−3

D) 6.1

E) 61

23) At elevated temperatures, molecular hydrogen and molecular bromine react to partially form hydrogen

bromide:

2 2H (g) Br (g) 2HBr (g)+ ˆ ˆ †‡ ˆ ˆ

A mixture of 0.682 mol of H

2 and 0.440 mol of

Br

2 is combined in a reaction vessel with a volume of 2.00

L. At equilibrium at 700 K, there are 0.566 mol of H

2 present. At equilibrium, there are __________ mol

of Br

2 present in the reaction vessel.

A) 0.000

B) 0.440

C) 0.566

D) 0.232

E) 0.324

24) An aqueous solution contains 0.100 M NaOH at 25.0 °C. The pH of the solution is __________.

A) 0.100

B) 1.00

C) 13.00

D) 7.00

E) -1.00

25) The pH of a 0.55 M aqueous solution of hypobromous acid, HBrO, at 25.0 °C is 4.48. What is the value

of Ka

for HBrO?

A) 92.0 10−×

B) 91.1 10−×

C) 56.0 10−×

D) 53.3 10−×

E) 43.0 10×

26) The pH of a 0.10 M solution of a weak base is 9.82. What is the Kb

for this base?

A) 42.1 10−×

B) 84.4 10−×

C) 88.8 10−×

D) 46.6 10−×

E) 52.0 10−×

27) The Ka

for HCN is 104.9 10−× . What is the value of K

b for CN− ?

A) 52.0 10−×

B) 64.0 10−×

C) 44.9 10×

D) 244.9 10−×

E) 92.0 10×

28) The molar concentration of hydroxide ion in pure water at 25 °C is __________.

A) 1.00

B) 0.00

C) 141.0 10−×

D) 7 1.0 10−×

E) 7.00

29) Of the following acids, __________ is not a strong acid.

A) 2HNO

B) 2 4H SO

C) 3HNO

D) 4HClO

E) HCl

30) Which one of the following is the weakest acid?

A) 4HF (K 6.8 10 )a

−= ×

B) 8HClO (K 3.0 10 )a

−= ×

C) 4

2HNO (K 4.5 10 )a

−= ×

D) 10HCN (K 4.9 10 )a

−= ×

E) Acetic acid 5( K 1.8 10 )a

−= ×

31) Using the data in the table, which of the conjugate acids below is the weakest acid?

A) 4NH +

B) 5 5C H NH+

C) 3H NOH+

D) 3 3NH CH +

E) 4NH + and 3 3NH CH +

32) Of the following, which is the strongest acid?

A) HClO

B) 3HClO

C) 2HClO

D) 4HClO

E) HIO

33) The pH of a solution that contains 0.818 M acetic acid (5K 1.76 10

a−

= × ) and 0.172 M sodium acetate

is __________.

A) 4.077

B) 5.434

C) 8.571

D) 8.370

E) 9.922

34) The Kb of ammonia is 51.77 10−× . The pH of a buffer prepared by combining 50.0 mL of 1.00 M

ammonia and 50.0 mL of 1.00 M ammonium nitrate is __________.

A) 4.63

B) 9.25

C) 4.74

D) 9.37

E) 7.00

35) Calculate the pH of a solution prepared by dissolving 0.370 mol of formic acid 2(HCO H) and 0.230

mol of sodium formate 2(NaCO H) in water sufficient to yield 1.00 L of solution. The Ka of formic acid is 41.77 10−

× .

A) 2.099

B) 10.463

C) 3.546

D) 2.307

E) 3.952

36) A 25.0 mL sample of 0.723 M 4HClO is titrated with a 0.273 M KOH solution. What is the [H ]+

(molarity) before any base is added?

A) 0.439

B) 71.00 10−×

C) 0.723

D) 132.81 10−×

E) 0.273

37) A 25.0 mL sample of 0.723 M 4HClO is titrated with a 0.273 M KOH solution. The 3H O+

concentration after the addition of 10.0 mL of KOH is __________ M.

A) 0.438

B) 71.00 10−×

C) 0.723

D) 132.81 10−×

E) 0.273

38) A 25.0 mL sample of 0.723 M 4HClO is titrated with a 0.273 M KOH solution. The 3H O+

concentration after the addition of 66.2 mL of KOH is __________ M.

A) 0.439

B) 2.63×10-5

C) 0.723

D) 132.81 10−×

E) 0.273

39) A 25.0 mL sample of 0.723 M 4HClO is titrated with a 0.273 M KOH solution. The 3H O+

concentration after the addition of 80.0 mL of KOH is __________ M.

A) 0.40

B) 71 10−×

C) 0.70

D) 3.59×10-12

E) 24 10−×

40) The solubility of lead (II) chloride 2(PbCl ) is 21.6 10 M−× . What is the K

spof 2PbCl ?

A) 45.0 10−×

B) 64.1 10−×

C) 73.1 10−×

D) 51.6 10−×

E) 21.6 10−×

41) Calculate the maximum concentration (in M) of silver ions (Ag )+ in a solution that contains 0.025 M

of 2

3CO− .The K

sp of 2 3Ag CO is 128.1 10−

× .

A) 51.8 10−×

B) 61.4 10−×

C) 62.8 10−×

D) 103.2 10−×

E) 128.1 10−×

42) Which one of the following pairs cannot be mixed together to form a buffer solution?

A) 5 5C H N , 5 5C H NHCl (pyridine is a weak base, Kb for C5H5N is 1.8 x 10-9

, pyridinium chloride its

conjugate weak acid)

B) 2 3 2HC H O , 2 3 2NaOH (C H O acetate)−= (acetic acid is a weak acid, NaOH strong base)

C) KOH, HI (strong acid, strong base)

D) 2 3NH CH , HCl (methyl amine is a weak base, HCl strong acid)

E) NaClO, 3HNO (NaClO is a weak base, HNO3 strong acid)

43) Which of the following could be added to a solution of acetic acid to prepare a buffer?

A) sodium hydroxide

B) hydrochloric acid

C) nitric acid

D) more acetic acid

E) None of the above can be added to an acetic acid solution to prepare a buffer.

Consider the following table of Ksp

values.

44) Which compound listed below has the greatest molar solubility in water?

A) 3CdCO

B) 2Cd(OH)

C) AgI

D) 2CaF

E) 3ZnCO

45) Which compound listed below has the smallest molar solubility in water?

A) 3ZnCO

B) 2Cd(OH)

C) 3CdCO

D) AgI

E) 2CaF

45) Calculate the percent ionization of formic acid 2(HCO H) in a solution that is 0.311 M in formic acid

and 0.189 M in sodium formate 2(NaHCO ) . The Ka of formic acid is 41.77 10−× .

A) 37.8

B) 0.0937

C) 11.3

D) 31.06 10−×

E) 3.529

46) The value of S∆ ° for the catalytic hydrogenation of acetylene to ethene,

2 2 2 2 4C H (g) H (g) C H (g)+ →

is __________ J/K· mol.

A) +18.6

B) +550.8

C) +112.0

D) -112.0

E) -18.6

47) The combustion of acetylene in the presence of excess oxygen yields carbon dioxide and water:

2 2 2 2 22C H (g) 5O 4CO (g) 2H O(l)+ → +

The value of S∆ ° for this reaction is __________ J/K· mol.

A) +689.3

B) +122.3

C) +432.4

D) -122.3

E) -432.4

48) Given the thermodynamic data in the table below, calculate the equilibrium constant (at 298 K) for the

reaction:

2 2 32SO (g) O (g) 2SO (g)+ ˆ ˆ †‡ ˆ ˆ

A) 242.37 10×

B) 1.06

C) 1.95

D) 233.82 10×

E) More data are needed.

49) The equilibrium constant for the following reaction is 85.0 10× at 25 C° .

2 2 3N (g) 3H (g) 2NH (g)+ ˆ ˆ †‡ ˆ ˆ

The value of G∆ ° for this reaction is __________ kJ/mol.

A) 22

B) -4.2

C) -25

D) -50

E) -22

50) A reaction that is spontaneous as written __________.

A) is very rapid

B) will proceed without outside intervention

C) is also spontaneous in the reverse direction

D) has an equilibrium position that lies far to the left

E) is very slow

51) S∆ is positive for the reaction __________.

A) 2 2 22H (g) O (g) 2H O(g)+ →

B) 2 2 42NO (g) N O (g)→

C) 2 2CO (g) CO (s)→

D) 2+

2BaF (s) Ba (aq) 2F (aq)−

→ +

E) 22Hg(l) O (g) 2HgO(s)+ →

DeltaHo = (2*-395) – (-2*297) = -196 kJ

DeltaSo= (2*256)-(2*249 + 1*205) = -191 J/K = -0.191 kJ/K

DeltaGo = DeltaH – TdeltaS = (-196 kJ) - 298K*(-0.191 kJ/K)

DeltaGo = -139 kJ = -1.39x10

5 J

DeltaG = -RTlnK so lnK = -(DeltaG)/RT

K = e^(-(DeltaG)/RT) = 2.4x1024

52) For the reaction

2 2C(s) H O(g) CO(g) H (g)+ → +

H 131.3 kJ / mol∆ ° = and S 133.6 J / Kmol∆ ° = at 298 K. At temperatures greater than __________°C this

reaction is spontaneous under standard conditions.

A) 273

B) 325

C) 552

D) 710

E) 983

53) A reaction that is not spontaneous at low temperature can become spontaneous at high temperature if

H∆ is __________ and S∆ is __________.

A) +, +

B) -, -

C) +, -

D) -, +

E) +, 0

54) __________ is reduced in the following reaction: 2 2 3 2

7 3 62 2 4 2Cr O 6S O 14H 2Cr 3S O 7H O− − + + −

+ + → + +

A) Cr6+

B) 2S +

C) +H

D) 2O −

E) 264

S O −

55) __________ is the oxidizing agent in the reaction below. 2 2 3 2

7 3 62 2 4 2Cr O 6S O 14H 2Cr 3S O 7H O− − + + −

+ + → + +

A) 272

Cr O −

B) 232

S O −

C) H+

D) 3Cr +

E) 264

S O −

56) __________ electrons appear in the following half-reaction when it is balanced.

2 2

6 34 2S O 2S O− −

→

A) 6

B) 2

C) 4

D) 1

E) 3

57) The electrode at which oxidation occurs is called the __________.

A) oxidizing agent

B) cathode

C) reducing agent

D) anode

E) voltaic cell

58) In a voltaic cell, electrons flow from the __________ to the __________.

A) salt bride, anode

B) anode, salt bridge

C) cathode, anode

D) salt bridge, cathode

E) anode, cathode

59) The more __________ the value of redE° , the greater the driving force for reduction.

A) positive

B) negative

C) exothermic

D) endothermic

E) extensive

Table 20.2

60) The standard cell potential cell(E° ) for the voltaic cell based on the reaction below is __________ V. 2 3 2 4Sn (aq) 2Fe (aq) 2Fe (aq) Sn (aq)+ + + +

+ → +

A) +0.46

B) +0.617

C) +1.39

D) -0.46

E) +1.21

61) The standard cell potential cell(E° ) for the voltaic cell based on the reaction below is __________ V. 4 3 23Sn (aq) 2Cr (s) 2cr (aq) 3Sn (aq)+ + +

+ → +

A) +1.94

B) +0.89

C) +2.53

D) -0.59

E) -1.02

Eocell = E

ored(cathode) – E

ored(anode)

(+0.771V) -(+0.154 V) + = 0.617 V

62) The standard cell potential cell(E° ) for the reaction below is +1.10 V. The cell potential for this reaction

is __________ V when the concentration of 2 5[Cu ] 1.0 10 M+ −

= × and 2[Zn ] 1.0 M+

=

2 2Zn (s) Cu (aq) Cu (s) Zn (aq)+ +

+ → +

A) 1.40

B) 1.25

C) 0.95

D) 0.80

E) 1.10

63) How many minutes will it take to plate out 2.19 g of chromium metal from a solution of 3Cr + using a

current of 35.2 amps in an electrolyte cell?

A) 5.77

B) 346

C) 115

D) 1.92

E) 17.3

64) What is the oxidation number of sulfur in the 4

HSO − ion?

A) -2

B) +1

C) +2

D) +4

E) +6

65) By what process does thorium-230 decay to radium-226?

A) gamma emission

B) alpha emission

C) beta emission

D) electron capture

E) positron emission

66) In balancing the nuclear reaction 238 234 4U E He92 90 2

→ + , the identity of element E is __________.

A) Pu

B) Np

C) U

D) Pa

E) Th

E = E0 –(0.0592/2) ln {[Zn

2+]/[Cu

2+]}

E = 1.10V –(0.0592/2) ln {[Zn2+

]/[Cu2+

]}

E = 1.10V –(0.0592/2) ln {1.0/1.0x10-5

} = 0.95V

67) This reaction is an example of __________.

41 41Ca K _____20 19

→ +

A) alpha decay

B) beta decay

C) positron decay

D) electron capture

E) gamma emission

68) Nuclei above the belt of stability can lower their neutron-to-proton ratio by __________.

A) beta emission

B) gamma emission

C) positron emission

D) electron capture

E) Any of the above processes will lower the neutron-to-proton ratio.

69) Bombardment of uranium-235 with a neutron generates tellurium-135, 3 neutrons, and __________.

A) zirconium-98.

B) krypton-101.

C) krypton-103.

D) strontium-99.

E) zirconium-99.

70) 131I has a half-life of 8.04 days. Assuming you start with a 1.53 mg sample of 131I, how many mg will

remain after 13.0 days?

A) 0.835

B) 0.268

C) 0.422

D) 0.440

E) 0.499

71) Which one of the following is a correct representation of a beta particle?

A) 4e2

B) 1β0

C) 0e1

D) 0e1−

E) 2β4

72) When two atoms of 2H are fused to form one atom of 4He, the total energy evolved is 123.83 10 J−×

What is the total change in mass (in kg) for this reaction? 8(C 3.00 10 m s)= ×

A) 171.28 10−×

B) 264.26 10−×

C) 83.45 10×

D) 1.15

E) 294.26 10−×

73) The mass of a proton is 1.00728 amu and that of a neutron is 1.00867 amu. What is the mass defect (in

amu) of a 60 Ni29

nucleus? (The mass of a nickel-60 nucleus is 59.9308 amu.)

A) 0.5449

B) 1.2374

C) 0.5491

D) 28.7930

E) 1.3066

74) The half-life of cobalt-60 is 5.20 yr. How many milligrams of a 2.000-mg sample remains after 6.55

years?

A) 0.837

B) 153.23 10−×

C) 4.779

D) 1.588

E) 1.163