Chapter 18 2 How many grams of nickel metal are plated out when a constant

5) Balance the following redox reaction if it occurs in basic solution. What are the coefficients in front

of Cr and Cl2 in the balanced reaction?

Cr(s) + Cl2(g) → Cr3+(aq) + Cl–(aq)

A) Cr = 2, Cl2 = 3

B) Cr = 2, Cl2 = 6

C) Cr = 1, Cl2 = 1

D) Cr = 2, Cl2 = 1

E) Cr = 3, Cl2 = 2

6) Determine the redox reaction represented by the following cell notation.

Fe(s) ∣ Fe2+(aq) ∣∣ Cu2+(aq) ∣ Cu(s)

A) Cu(s) + Fe2+(aq) → Fe(s) + Cu2+(aq)

B) Fe(s) + Cu2+(aq) → Cu(s) + Fe2+(aq)

C) 2 Fe(s) + Cu2+(aq) → Cu(s) + 2 Fe2+(aq)

D) 2 Cu(s) + Fe2+(aq) → Fe(s) + 2 Cu2+(aq)

E) 3 Fe(s) + 2 Cu2+(aq) → 2 Cu(s) + 3 Fe2+(aq)

7) Determine the cell notation for the redox reaction given below.

Cd(s) + 2 Ag⁺(aq) → Cd2+(aq) + 2 Ag(s)

A) Ag+(aq) ∣ Ag(s) ∣∣ Cd(s) ∣ Cd2+(aq)

B) Ag(s) ∣ Ag+(aq) ∣∣ Cd2+(aq) ∣ Cd(s)

C) Cd(s) ∣ Cd2+(aq) ∣∣ Ag+(aq) ∣ Ag(s)

D) Cd2+(aq) ∣ Cd(s) ∣∣ Ag(s) ∣ Ag+(aq)

E) Cd(s) ∣ Ag(s) ∣∣ Cd2+(aq) ∣ Ag+(aq)

8) Determine the cell notation for the redox reaction given below.

Sn(s) + 2 H⁺(aq) → Sn2+(aq) + H2(g)

A) H+(aq) ∣ H2(g) ∣ Pt ∣∣ Sn(s) ∣ Sn2+(aq)

B) H2(g) ∣ H+(aq) ∣ Pt ∣∣ Sn2+(aq) ∣ Sn(s)

C) Sn2+(aq) ∣ Sn(s) ∣∣ H2(g) ∣ H+(aq) ∣ Pt

D) Sn(s) ∣ Sn2+(aq) ∣∣ H+(aq) ∣ H2(g) ∣ Pt

E) Sn(s) ∣ H2(g) ∣∣ Sn2+(aq) ∣ H+(aq) ∣ Pt

9) What is the reduction half-reaction for the following overall galvanic cell reaction?

Co2+(aq) + 2 Ag(s) → Co(s) + 2 Ag+(aq)

A) Ag(s) + e– → Ag+(aq)

B) Ag+(aq) + e– → Ag(s)

C) Co2+(aq) + 2 e– → Co(s)

D) Co2+(aq) + e– → Co(s)

10) What is the shorthand notation that represents the following galvanic cell reaction?

Pb(s) + Cu(NO3)2(aq) → Pb(NO3)2(aq) + Cu(s)

A) Pb(s) ∣ Pb2+(aq) ∣∣ Cu2+(aq) ∣ Cu(s)

B) Cu(s) ∣ Cu2+(aq) ∣∣ Pb2+(aq) ∣ Pb(s)

C) Pb(s) ∣ NO3–(aq) ∣∣ NO3–(aq) ∣ Cu(s)

D) Cu(s) ∣ Cu(NO3)2(aq) ∣∣ Pb(NO3)2(aq) ∣ Pb(s)

11) What is the shorthand notation that represents the following galvanic cell reaction?

2 Fe2+(aq) + F2(g) → 2 Fe3+(aq) + 2 F–(aq)

A) Fe2+(aq) ∣ Fe3+(aq) ∣∣ F2(g) ∣ F–(aq)

B) Fe(s) ∣ Fe2+(aq) ∣∣ Fe3+(aq) F2(g) ∣ F–(aq) ∣ C(s)

C) Pt(s) ∣ Fe3+(aq), Fe2+(aq), F2(g) ∣∣ F–(aq) ∣ C(s)

D) Pt(s) ∣ Fe2+(aq), Fe3+(aq) ∣∣ F2(g) ∣ F–(aq) ∣ C(s)

12) For the galvanic cell reaction, expressed below using shorthand notation, what half-reaction occurs

at the cathode?

Zn(s) ∣ Zn2+(aq) ∣∣ Ni2+(aq) ∣ Ni(s)

A) Zn(s) → Zn2+(aq) + 2 e–

B) Zn2+(aq) + 2 e– → Zn(s)

C) Ni(s) → Ni2+(aq) + 2 e–

D) Ni2+(aq) + 2 e– → Ni(s)

13) What is the balanced chemical equation for the galvanic cell reaction expressed using shorthand

notation below?

Al(s) ∣ Al3+(aq) ∣∣ Fe2+(aq) ∣ Fe(s)

A) 2 Al(s) + 3 Fe2+(aq) → 2 Al3+(aq) + 3 Fe(s)

B) 3 Al(s) + 2 Fe2+(aq) → 3 Al3+(aq) + 2 Fe(s)

C) 2 Fe(s) + 3 Al3+(aq) → 2 Fe2+(aq) + 3 Al(s)

D) 3 Fe(s) + 2 Al3+(aq) → 3 Fe2+(aq) + 2 Al(s)

14) What is the balanced equation for the galvanic cell reaction expressed using shorthand notation

below?.

Ni(s) ∣ Ni2+(aq) ∣∣ Cl2(g) ∣ Cl–(aq) ∣ C(s)

A) Ni(s) + 2 Cl–(aq) → Ni2+(aq) + Cl2(g)

B) Ni(s) + Cl2(g) → Ni2+(aq) + 2 Cl–(aq)

C) Ni2+(aq) + 2 Cl–(aq) → Ni(s) + Cl2(g)

D) Ni2+(aq) + 2 Cl–(aq) → NiCl2(s)

15) What is the reducing agent in the redox reaction represented by the following cell notation?

Zn(s) ∣ Zn2+(aq) ∣∣ Ag+(aq) ∣ Ag(s)

A) Zn(s)

B) Zn2+(aq)

C) Ag+(aq)

D) Ag(s)

E) Pt

22

16) What is the oxidizing agent in the redox reaction represented by the following cell notation?

Ni(s) ∣ Ni2+(aq) ∣∣ Ag+(aq) ∣ Ag(s)

A) Ni(s)

B) Ni2+(aq)

C) Ag+(aq)

D) Ag(s)

E) Pt

17) What is the oxidizing agent in the redox reaction represented by the following cell notation?

Sn(s) ∣ Sn2+(aq) ∣∣ Ag+(aq) ∣ Ag(s)

A) Sn(s)

B) Ag+(aq)

C) Sn2+(aq)

D) Ag(s)

E) Pt

18) What is the reducing agent in the redox reaction represented by the following cell notation?

Ca(s) ∣ Ca2+(aq) ∣∣ Ag+(aq) ∣ Ag(s)

A) Ca(s)

B) Ag+(aq)

C) Ca2+(aq)

D) Ag(s)

E) Pt

19) What is undergoing reduction in the redox reaction represented by the following cell notation?

Cr(s) ∣ Cr3+(aq) ∣∣ F2(g) ∣ F⁻(aq) ∣ Pt

A) Cr(s)

B) Cr3+(aq)

C) F2(g)

D) F⁻(aq)

E) Pt

20) What is undergoing oxidation in the redox reaction represented by the following cell notation?

Fe(s) ∣ Fe3+(aq) ∣∣ Br2(g) ∣ Br⁻(aq) ∣ Pt

A) Fe(s)

B) Fe3+(aq)

C) Br2(g)

D) Br⁻(aq)

E) Pt

21) What is undergoing oxidation in the redox reaction represented by the following cell notation?

Fe(s) ∣ Fe2+(aq) ∣∣ H+(aq) ∣ H2(g) ∣ Pt

A) H2(g)

B) H+(aq)

C) Fe2+(aq)

D) Fe(s)

E) Pt

22) What is undergoing reduction in the redox reaction represented by the following cell notation?

Pb(s) ∣ Pb2+(aq) ∣∣ H+(aq) ∣ H2(g) ∣ Pt

A) H2(g)

B) H+(aq)

C) Pb2+(aq)

D) Pb(s)

E) Pt

23) Which of the following is the strongest reducing agent?

A) Cl2+(aq)

B) Cr3+(aq)

C) Cl–(aq)

D) Cr(s)

E) Cl(s)

24) Which of the following is the weakest oxidizing agent?

A) Sn2+(aq)

B) Al3+(aq)

C) Sn4+(aq)

D) K+(s)

E) Cu+(s)

25) Which of the following is the strongest reducing agent?

A) Na(s)

B) Li+(aq)

C) Ca(s)

D) Ca2+(aq)

E) K(s)

26) Which of the following is the strongest reducing agent?

A) Al(s)

B) Mn(s)

C) Li(s)

D) Al3+(aq)

E) Mg2+(aq)

27) Which of the following is the weakest reducing agent?

A) Cr(s)

B) F–(aq)

C) K(s)

D) Cr3+(aq)

E) Ca2+(aq)

28) Which of the following is the strongest oxidizing agent?

A) BrO2(s)

B) Br⁻(aq)

C) Cu⁺(aq)

D) SO42-(aq)

E) MnO4⁻(aq)

29) Which of the following is the strongest oxidizing agent?

A) Br2(l)

B) Au3+(aq)

C) Li(s)

D) I⁻(aq)

E) Li(s)

30) Which of the following is the weakest reducing agent?

A) Cl2(l)

B) ClO2–(aq)

C) Ag(s)

D) Br⁻(aq)

E) Au(s)

31) Which of the following is the strongest oxidizing agent?

A) H2O2(aq)

B) Fe3+(aq)

C) ClO2(g)

D) I2(s)

E) Fe(s)

32) Determine which of the following pairs of reactants will result in a spontaneous reaction at 25°C.

A) Pb2+(aq) + Cu(s)

B) Ag+(aq) + Br⁻(aq)

C) Li+(aq) + Cr(s)

D) Fe3+(aq) + Cd(s)

E) None of the above pairs will react.

33) Determine which of the following pairs of reactants will result in a spontaneous reaction at 25°C.

A) Sn4+(aq) + Mn(s)

B) Cr3+(aq) + Pb(s)

C) Zn(s) + K+(aq)

D) Fe(s) + Ba2+(aq)

E) None of the above pairs will react.

34) Determine which of the following pairs of reactants will result in a spontaneous reaction at 25°C.

A) I–(aq) + Fe2+(aq)

B) Ca(s) + Mg2+(aq)

C) H2(g) + Sn2+(aq)

D) Ag(s) + Sn2+(aq)

E) All of the above pairs will react.

35) Which of the following metals will dissolve in nitric acid but not hydrochloric?

A) Li

B) Li

C) Cu

D) Sn

E) Ni

36) Which of the following metals will dissolve in nitric acid but not hydrochloric?

A) Fe

B) Zn

C) Mg

D) Ag

E) Al

37) Which of the following metals will dissolve in HCl?

A) Ba

B) Na

C) Mn

D) Al

E) all of the above

38) Which of the following metals will not dissolve in nitric acid or hydrochloric acid?

A) Pb

B) Cu

C) Ni

D) Au

E) all of the above

39) Which of the following metals will not dissolve in nitric acid or hydrochloric acid?

A) Al

B) Pb

C) Mg

D) K

E) none of the above

40) A galvanic cell consists of a Ni2+/Ni half-cell and a standard hydrogen electrode. If the Ni2+/Ni

half-cell standard cell functions as the anode, and the standard cell potential is 0.26 V, what is the

standard reduction potential for the Ni2+/Ni half-cell?

A) -0.26 V

B) -0.13 V

C) +0.13 V

D) +0.26 V

41) A galvanic cell consists of one half-cell that contains Ag(s) and Ag+(aq), and one half-cell that

contains Cu(s) and Cu2+(aq). What species are produced at the electrodes under standard conditions?

Ag+(aq) + e– → Ag(s) E° = +0.80 V

Cu2+(aq) + 2 e– → Cu(s) E° = +0.34 V

A) Ag(aq) is formed at the cathode and, Cu(s) is formed at the anode.

B) Ag(s) is formed at the cathode, and Cu2+(aq) is formed at the anode.

C) Cu(s) is formed at the cathode, and Ag+(aq) is formed at the anode.

D) Cu2+(aq) is formed at the cathode, and Cu(s) is formed at the anode.

42) Consider the following standard reduction potentials,

Ni2+(aq) + 2 e– → Ni(s) E° = -0.26 V

I2(s) + 2 e– → 2 I–(aq) E° = +0.54 V

Under standard conditions,

A) Ni2+(aq) is a stronger oxidizing agent than I2(s) and I–(aq) is a stronger reducing agent than Ni(s).

B) I2(s) is a stronger oxidizing agent than Ni2+(aq) and Ni(s) is a stronger reducing agent than I–(aq).

C) Ni(s) is a stronger oxidizing agent than I–(aq) and Ni2+(aq) is a stronger reducing agent than I2(s).

D) I–(aq) is a stronger oxidizing agent than Ni(s) and I2(s) is a stronger reducing agent than Ni2+(aq).

43) Consider the galvanic cell, Zn(s) ∣ Zn2+(aq) ∣∣ Pb2+(aq) ∣ Pb(s). Which one of the following

changes to the cell would cause the cell potential to increase (i.e., become more positive)?

A) increase the [Zn2+] concentration

B) increase the [Pb2+] concentration

C) increase the mass of Zn(s)

D) decrease the mass of Zn(s)

44) Based on the following information,

Cl2(g) + 2 e– → 2 Cl–(aq) E° = +1.36 V

Mg2+(aq) + 2 e– → 2 Mg(s) E° = -2.37 V

which of the following chemical species is the strongest reducing agent?

A) Cl2(g)

B) Mg2+(aq)

C) Cl–(aq)

D) Mg(s)

45) Using the following standard reduction potentials,

Fe3+(aq) + e– →Fe2+(aq) E° = +0.77 V

Ni2+(aq) + 2 e– →Ni(s) E° = -0.23 V

calculate the standard cell potential for the galvanic cell reaction given below, and determine whether or

not this reaction is spontaneous under standard conditions.

Ni2+(aq) + 2 Fe2+(aq) → 2 Fe3+(aq) + Ni(s)

A) E° = -1.00 V, nonspontaneous

B) E° = -1.00 V, spontaneous

C) E° = +1.00 V, nonspontaneous

D) E° = +1.00 V, spontaneous

46) How many electrons are transferred in the following reaction? (The reaction is unbalanced.)

Ca(s) + Cr3+(aq) → Cr(s) + Ca2+(aq)

A) 6

B) 2

C) 3

D) 1

E) 4

29

47) How many electrons are transferred in the following reaction? (The reaction is unbalanced.)

Ca2+(aq) + Li(s) → Ca(s) + Li+(aq)

A) 1

B) 2

C) 3

D) 4

E) 6

48) The gas OF2 can be produced from the electrolysis of an aqueous solution of KF, as shown in the

equation below.

OF2(g) + 2 H+(aq) + 4 e– → H2O(l) + 2 F–(aq) E° = +2.15 V

Using the given standard reduction potential, calculate the amount of OF2 that is produced, and the

electrode at which the OF2 is produced, upon the passage of 0.480 faradays through an aqueous KF

solution.

A) 6.48 g of OF2 at the anode.

B) 26.0 g of OF2 at the anode.

C) 6.48 g of OF2 at the cathode.

D) 26.0 g of OF2 at the cathode.

49) Given that E°red = -0.40 V for Cd2+/Cd at 25°C, find E° and E for the concentration cell expressed

using shorthand notation below.

Cd(s) ∣ Cd2+(1.0 × 10-5 M) ∣∣ Cd2+(0.100 M) ∣ Cd(s)

A) E° = 0.00 V and E = +0.24 V

B) E° = 0.00 V and E = +0.12 V

C) E° = -0.40 V and E = -0.16 V

D) E° = -0.40 V and E = -0.28 V

30

50) The standard cell potential (E°) of a voltaic cell constructed using the cell reaction below is 0.76 V:

Zn(s) + 2H+ (aq) → Zn2+ (aq) + H2(g)

With PH2 = 1.0 atm and [Zn2+] = 1.0 M, the cell potential is 0.66 V. The concentration of H+ in the

cathode compartment is ________ M.

A) 2.0 × 10-2

B) 4.2 × 10-4

C) 1.4 × 10-1

D) 4.9 × 101

E) 1.0 × 10-12

51) A voltaic cell is constructed with two silver-silver chloride electrodes, where the half-reaction is

AgCl(s) + e– → Ag(s) + Cl– (aq) E° = +0.222 V

The concentrations of chloride ion in the two compartments are 0.0222 M and 2.22 M, respectively. The

cell emf is ________ V.

A) 0.212

B) 0.118

C) 0.00222

D) 22.2

E) 0.232

52) A voltaic cell is constructed with two Zn2+-Zn electrodes, where the half-reaction is

Zn2+ + 2e– → Zn(s) E° = -0.763 V

The concentrations of zinc ion in the two compartments are 5.50 M and 1.11 × 10-2 M, respectively.

The cell emf is ________ V.

A) -1.54 × 10-3

B) -378

C) 0.0798

D) 0.160

E) -0.761

53) The standard emf for the cell using the overall cell reaction below is +2.20 V:

2Al(s) + 3I2 (s) → 2Al3+ (aq) + 6I– (aq)

The emf generated by the cell when [Al3+] = 4.5 × 10-3 M and [I–] = 0.15 M is ________ V.

A) 2.20

B) 2.32

C) 2.10

D) 2.39

E) 2.23

54) The standard emf for the cell using the overall cell reaction below is +0.48 V:

Zn(s) + Ni2+ (aq) → Zn2+ (aq) + Ni(s)

The emf generated by the cell when [Ni2+] = 2.50 M and [Zn2+] = 0.100 M is ________ V.

A) 0.40

B) 0.50

C) 0.52

D) 0.56

E) 0.44

55) The electrolysis of molten AlCl3 for 3.25 hr with an electrical current of 15.0 A produces ________

g of aluminum metal.

A) 147

B) 0.606

C) 4.55 × 10-3

D) 16.4

E) 49.1

56) For a galvanic cell that uses the following two half-reactions,

Cr2O72-(aq) + 14 H+(aq) + 6 e– → 2 Cr3+(aq) + 7 H2O(l)

Pb(s) → Pb2+(aq) + 2 e–

how many moles of Pb(s) are oxidized by three moles of Cr2O72-?

A) 3

B) 6

C) 9

D) 18

57) How many kilowatt-hours of electricity are used to produce 3.00 kg of magnesium in the electrolysis

of molten MgCl2 with an applied emf of 4.50 V?

A) 0.0336

B) 0.0298

C) 7.4

D) 29.8

E) 14.9

58) The most useful ore of aluminum is bauxite, in which Al is present as hydrated oxides, Al2O3 ∙

xH2O. The number of kilowatt-hours of electricity required to produce 4.00 kg of aluminum from

electrolysis of compounds from bauxite is ________ when the applied emf is 5.00 V.

A) 0.0168

B) 0.0596

C) 39.7

D) 19.9

E) 59.6

59) How many seconds are required to produce 4.00 g of aluminum metal from the electrolysis of

molten AlCl3 with an electrical current of 12.0 A?

A) 27.0

B) 9.00

C) 1.19 × 103

D) 2.90 × 105

E) 3.57 × 103

60) How many grams of chromium metal are plated out when a constant current of 8.00 A is passed

through an aqueous solution containing Cr3+ ions for 320. minutes?

A) 27.6 g

B) 49.2 g

C) 82.4 g

D) 248 g

61) How many grams of nickel metal are plated out when a constant current of 15.0 A is passed through

aqueous NiCl2 for 60.0 minutes?

A) 10.9 g

B) 16.4 g

C) 32.8 g

D) 36.3 g

62) How long must a constant current of 50.0 A be passed through an electrolytic cell containing

aqueous Cu2+ ions to produce 5.00 moles of copper metal?

A) 0.187 hours

B) 0.373 hours

C) 2.68 hours

D) 5.36 hours

63) The town of Natrium, West Virginia, derives its name from the sodium produced in the electrolysis

of molten sodium chloride (NaCl) mined from ancient salt deposits. The number of kilowatt-hours of

electricity required to produce 4.60 kg of metallic sodium from the electrolysis of molten NaCl(s) is

________ when the applied emf is 4.50 V.

A) 24.1

B) 0.0414

C) 0.0241

D) 48.3

E) 12.1

Matching Questions

Match the following.

A) Ecell = E°cell

B) Ecell > 0

C) E°cell > 0

D) Ecell = 0

E) Ecell < 0

F) E°cell < 0

1) Q = 1

Diff: 1 Page Ref: 18.6

2) Q > K

Diff: 1 Page Ref: 18.6

3) Q < K

Diff: 1 Page Ref: 18.6

4) ΔG° < 0

Diff: 1 Page Ref: 18.6

5) ΔG° > 0

Diff: 1 Page Ref: 18.6

6) Q = K

Diff: 1 Page Ref: 18.6

Short Answer Questions

1) What is the difference between a voltaic cell and an electrolytic cell?

2) Sketch a voltaic cell that contains the following half reactions and label all relevant components.

Zn2+(aq) + 2e⁻ → Zn(s) E°= -0.76 V

Cu2+(aq) + 2e⁻ → Cu(s) E°= +0.34 V

3) Give an example of an inert electrode.

4) Explain the significance of the standard hydrogen electrode (SHE) in the tabulation of standard

reduction potentials of other species.

5) Why, if we multiply a reaction by 2, don’t we multiply its E°red by 2?

6) What is electrolysis?

7) Why is sugar water not a good conductor of current?

8) Why are iron nails coated with zinc?