Name Date Period - Quia

Name DatePeriod

A) 0 B) 6 C) 8 D) 4 E) 10

1. How many electrons are needed to balance thehalf–reaction?

SO42– + 8 H+ + ? e– ®S2– + 4 H2O

A) anode, where oxidation occursB) anode, where reduction occursC) cathode, where oxidation occursD) cathode, where reduction occurs

2. In an electrolytic cell, the positive electrode is the

A) AgNO3 + NaCl ® AgCl + NaNO3

B) Cu + FeCl2 ® CuCl2 + FeC) Zn + 2 HCl ® ZnCl2 + H2

D) 2 Al + 3 Ni(NO3)2 ® 2 Al(NO3)3 + 3 Ni

3. For which chemical reaction must an electrolytic cell beused?

A) Cu2+ ions migrate toward the positive electrode.B) Cl– ions migrate toward the negative electrode.C) Cu2+ ions are reduced.D) Cl– ions are reduced.

4. Which occurs in an electrolytic cell containing CuCl2(aq)?

A) a chemical cell, because it is exothermicB) an electrolytic cell, because it is exothermicC) a chemical cell, because it is endothermicD) an electrolytic cell, because it is endothermic

5. Given the reaction:

2 H2O + electricity ® 2 H2 + O2

In which type of cell would this reaction most likelyoccur?

A) Ag0 + 1e– ® Ag+ B) Ag0 ® Ag+ + 1e–

C) Ag+ + 1e– ® Ag0 D) Ag+ ® Ag0 + 1e–

6. Which half-reaction occurs at the negative electrode inan electrolytic cell in which an object is being platedwith silver?

7. The diagram below represents an electrochemical cell.

A) Zn is reduced.B) Cu is oxidized.C) Electrons flow from Cu to Zn.D) Electrons flow from Zn to Cu.

What occurs when the switch is closed?

8. Base your answer to the following question on thediagram below of an electrolytic cell in which theelectrodes are tin and copper.

A) anode and is positiveB) anode and is negativeC) cathode and is positiveD) cathode and is negative

In this electrolytic cell, electrode A is designated as the

Name DatePeriod

A) It produces electrical energy.B) It requires an external energy source.C) It uses radioactive nuclides.D) It undergoes a spontaneous redox reaction.

9. Which statement describes one characteristic of anoperating electrolytic cell?

10. Base your answer to the following question on thediagram below which represents the electroplating of ametal fork with Ag(s).

A) Ag+ + NO3– ® AgNO3

B) AgNO3 ® Ag+ + NO3–

C) Ag+ + e– ® Ag(s)D) Ag(s) ® Ag+ + e–

Which equation represents the half-reaction that takesplace at the fork?

A) chemical to electricalB) electrical to chemicalC) chemical to nuclearD) nuclear to chemical

11. Which energy change occurs in an operating voltaiccell?

A) Sn4+ ® Sn2+ + 2e–

B) Sn2+ ® Sn4+ + 2e–

C) Sn4+ + 2e– ® Sn2+

D) Sn2+ + 2e– ® Sn4+

E) Sn4+ + Sn2+ ® Sn6+ + 2e–

12. Which half–cell reaction correctly represents reduction?

A) Ag B) Zn C) Pb D) K

13. Which metal can be produced only by the electrolysisof its fused salt?

14. The diagram below shows a key being plated withcopper in an electrolytic cell

A) A, which is the anodeB) A, which is the cathodeC) B, which is the anodeD) B, which is the cathode

Given the reduction reaction for this cell:

Cu2+(aq) + 2e- ® Cu(s)

This reduction occurs at

A) (–), oxidationB) (+), oxidationC) (–), reductionD) (+), reductionE) no reaction occurs at the cathode

15. At the cathode during electrolysis, what is its chargeand what type of reaction occurs.

A) anode to the cathode through the wireB) cathode to the anode through the wireC) anode to the cathode through the salt bridgeD) cathode to the anode through the salt bridgeE) anode to the cathode through the wire and cathode

to the anode through the salt bridge

16. In an electrochemical cell, the electrons go from the

Name DatePeriod

A) neutralization B) esterificationC) electrolysis D) hydrolysis

17. The reaction 2 H2O ( ) ® 2 H2(g) + O2(g) is forced tooccur by use of an externally applied electric current.This procedure is called

A) in the wire B) at the anodeC) at the cathode D) at the salt bridgeE) in solution

18. Electroplating always takes place

A) 2 H2O( ) ® 2 H2(g) + O2(g)B) 2 HgO(s) ® 2 Hg( ) + O2(g)C) 2 KClO3( ) ® 2 KCl(s) + 3 O2(g)D) MgCO3(s) ® MgO(s) + CO2(s)

19. Which net reaction occurs by the process ofelectrolysis?

A) Anode: 2 Cl– ® Cl2 + 2e– Cathode: 2 Na+ + 2e– ® 2 Na

B) Anode: 2 Cl– ® Cl2 + 2e– Cathode: 2 H2O + 2e– ® H2 + 2 OH–

C) Anode: 2 H2O ® O2 + 4 H+ + 4e– Cathode: 4Na+ + 4e– ® 4 Na

D) Anode: 2 H2O ® O2 + 4 H+ + 4e– Cathode: 4 H2O + 4e– ® 2 H2 + 4 OH–

E) Anode: Cl2 + 2e– ® 2 Cl– Cathode: 2 Na ® 2Na+ + 2e–

20. What are the anode and cathode half–reactions for theelectrolysis of fused (melted) NaCl?

A) Both occur at the anode.B) Both occur at the cathode.C) Oxidation occurs at the anode and reduction

occurs at the cathode.D) Oxidation occurs at the cathode and reduction

occurs at the anode.

21. Which statement is true about oxidation and reductionin an electrochemical cell?

22. A student wishes to set up an electrochemical cell. Thefollowing list of materials and equipment will be used:

• two 250-ml beakers• wire• one piece of Zn metal • 125 ml of 0.10 M Zn(NO3)2 • voltmeter • switch • one piece of Pb metal • 125 ml of 0.10 M Pb(NO3)2

A) an anodeB) a cathodeC) an external path for electronsD) a salt bridge

For the cell to operate properly, the student will alsoneed

A) 2 Cr(s) ® 2 Cr3+(aq) + 6e–

B) 3 Cu(s) ® 3 Cu2+(aq) + 6e–

C) 2 Cr3+(aq) + 6e– ® 2 Cr(s)D) 3 Cu2+(aq) + 6e– ® 3 Cu(s)E) It cannot be determined from the information

given

23. The net ionic reaction for an electrochemical cell is

2 Cr(s) + 3 Cu2+(aq) ®2 Cr3+(aq) + 3 Cu(s)

What is the reaction occurring at the cathode?

Name DatePeriod

A) Both Pb and Pb4+ undergo oxidation.B) Both Pb and Pb4+ undergo reduction.C) Pb is oxidized and Pb4+ is reduced.D) Neither the Pb nor the Pb4+ is oxidized or reduced.

24. What occurs during discharge in the lead-acid batteryreaction below?

Pb + PbO2 + 2 H2SO4 « 2 PbSO4 + 2 H2O

25. A diagram of a chemical cell and an equation are shownbelow.

A) the Pb(s) to the Cu(s)B) the Cu(s) to the Pb(s)C) the Pb2+(aq) to the Pb(s)D) the Cu2+(aq) to the Cu(s)

When the switch is closed, electrons will flow from

A) Cu anode to the Zn cathodeB) Cu cathode to the Zn anodeC) Zn anode to the Cu cathodeD) Zn cathode to the Cu anode

26. Given the balanced ionic equation representing thereaction in an operating voltaic cell: Zn(s) + Cu2+(aq) ® Zn2+(aq) + Cu(s)

The flow of electrons through the external circuit in thiscell is from the

27. Base your answer to the following question on thediagram of the chemical cell at 298 K and on theequation below.

A) gain electrons B) lose electronsC) gain protons D) lose protons

In the given reaction, the Ag+ ions

A) Na+ + 1e– ® Na0 B) Na0 ® Na+ + 1e–

C) 2 Cl– ® Cl20 + 2e– D) Cl20 + 2e– ® 2 Cl–

28. During the electrolysis of fused NaCl, whichhalf-reaction occurs at the negative electrode?

A) PbB) Pb2+

C) ZnD) Zn2+

E) It cannot be determined unless the potentials areknown.

29. To which electrode do the electrons move in the cell

Zn/Zn2+||Pb2+/Pb?

Name DatePeriod

30. A student collects the materials and equipment below toconstruct a voltaic cell:

• two 250-mL beakers• wire and a switch• one strip of magnesium• one strip of copper• 125 mL of 0.20 M Mg(NO3)2(aq)• 125 mL of 0.20 M Cu(NO3)2(aq)

A) an anode B) a batteryC) a cathode D) a salt bridge

Which additional item is required for the construction ofthe voltaic cell?

A) Sn2+ ® Sn4+ + 2e– B) Ag+ + e– ® AgC) Sn2+ + 2e– ® Sn4+ D) Ag+ ® Ag + e–

E) Sn2+ + Sn4+ ® 2e–

31. In the reaction

Sn2+(aq) + 2 Ag+(aq) ® Sn4+(aq) + 2 Ag(s)

What is the half–reaction equation for the oxidizingagent above?

32.

A) Cu2+ + 2e– ® Cu(s)B) Cu(s) ® Cu2+ + 2e–

C) 8 H+ + MnO4– + 5e– ® Mn2+ + 4 H2OD) Mn2+ + 4 H2O ® 8 H+ + MnO4– + 5e–

E) MnO4– + 8 H+ ® Mn2+ + 4 H2O

What is the oxidation half–reaction for the reaction? Cu + MnO4– + H+ ®Cu2+ + Mn2+ + H2O

A) increase the cell voltageB) maintain electrical neutralityC) increase the oxidation–reduction rateD) supply a travel pathway for electronsE) increase the rate of attainment of equilibrium

33. The function of the salt bridge in an electrochemicalcell is to

34. The diagram below shows the electrolysis of fused KCl.

A) Positive ions migrate toward the anode, where theylose electrons.

B) Positive ions migrate toward the anode, where theygain electrons.

C) Positive ions migrate toward the cathode, wherethey lose electrons.

D) Positive ions migrate toward the cathode, wherethey gain electrons.


A) light energy to chemical energyB) electrical energy to chemical energyC) chemical energy to light energyD) chemical energy to electrical energy

35. Which conversion of energy always occurs in a voltaiccell?

Name DatePeriod

36. The diagram below represents an operatingelectrochemical cell and the balanced ionic equation forthe reaction occurring in the cell.

A) Electrons flow through the salt bridge from theNi(s) to the Zn(s).

B) Electrons flow through the salt bridge from theZn(s) to the Ni(s).

C) Electrons flow through the wire from the Ni(s) tothe Zn(s).

D) Electrons flow through the wire from the Zn(s) tothe Ni(s).

Which statement identifies the part of the cell thatconducts electrons and describes the direction ofelectron flow as the cell operates?

A) anode B) cathodeC) salt bridge D) external circuit

37. When a voltaic cell operates, ions move through the

A) Ag B) Ag+

C) Mg D) Mg2+

E) both Ag and Mg

38. The negative ions go to which electrode in the voltaiccell

Mg/Mg2+||Ag+/Ag?

39. Given the redox reaction:

A) B)C) D)

Which species is oxidized during discharge?

A) CaB) Ca2+

C) Cl–

D) Cl2

E) Oxidation does not occur

40. In the electrolysis of molten CaCl2 , the speciesoxidized is

41. Which statement best describes the key?

A) It acts as the cathode and is negative.B) It acts as the cathode and is positive.C) It acts as the anode and is negative.D) It acts as the anode and is positive.

Name DatePeriod

42. Consider the reaction,

S6+ + ? e– ® S2–

A) 6 B) 2 C) 8 D) 4 E) 10

How many electrons are needed to reduce S6+ to S2–?

43. The diagram below shows a spoon that will beelectroplated with nickel metal.

A) The spoon will lose mass, and the Ni(s) will bereduced.

B) The spoon will lose mass, and the Ni(s) will beoxidized.

C) The spoon will gain mass, and the Ni(s) will bereduced.

D) The spoon will gain mass, and the Ni(s) will beoxidized.

What will occur when switch S is closed?

44. Which is the cathode of this electrochemical cell?

Cr + Au3+ ® Cr3+ + Au

A) CrB) Au3+

C) Cr3+

D) AuE) It cannot be determined unless the potentials are

known

A) anode to the cathode through the wireB) cathode to the anode through the wireC) anode to the cathode through the salt bridgeD) cathode to the anode through the salt bridgeE) cathode to the anode through the wire and anode to

the cathode through the salt bridge

45. In an electrochemical cell, the positive ions go from the

A) The reaction occurs in a chemical cell and releasesenergy.

B) The reaction occurs in a chemical cell and absorbsenergy.

C) The reaction occurs in an electrolytic cell andreleases energy.

D) The reaction occurs in an electrolytic cell andabsorbs energy.

46. Which statement best describes the reaction representedby the equation below?

2 NaCl + 2 H2O + electricity ® Cl2 + H2 + 2NaOH

Name DatePeriod

47. Base your answer to the following question on the diagram of the voltaic cell below.

When the switch is closed, in which half-cell does oxidation occur?

48. Base your answer to the following question on the diagram and balanced equation below, which representthe electrolysis of molten NaCl.

Write the balanced half-reaction for the reduction that occurs in this electrolytic cell.

Name DatePeriod

49. Base your answer to the following question on the information below.

A voltaic cell with magnesium and copper electrodes is shown in the diagram below. The copperelectrode has a mass of 15.0 grams.

When the switch is closed, the reaction in the cell begins. The balanced ionic equation for thereaction in the cell is shown below the cell diagram. After several hours, the copper electrode isremoved, rinsed with water, and dried. At this time, the mass of the copper electrode is greater than15.0 grams.

Explain, in terms of copper ions and copper atoms, why the mass of the copper electrode increases as thecell operates. Your response must include information about both copper ions and copper atoms.

Name DatePeriod

50. Base your answer to the following question on the information below. The diagram below represents an operating electrolytic cell used to plate silver onto a nickel key. Asthe cell operates, oxidation occurs at the silver electrode and the mass of the silver electrode decreases.

Explain, in terms of Ag atoms and Ag+(aq) ions, why the mass of the silver electrode decreases as the celloperates.

Name DatePeriod

51. Base your answer to the following question on theinformation below.

A student places a 2.50-gram sample ofmagnesium metal in a bottle and fits the bottle witha 2-hole stopper as shown in the diagram.Hydrochloric acid is added to the bottle, causing areaction. As the reaction proceeds, hydrogen gastravels through the tubing to an inverted bottle filledwith water, displacing some of the water in thebottle.

Based on Reference Table J, explain why Ag(s) will not react with HCl (aq) to generate H2(g).


Electroplating is an electrolytic process used to coatmetal objects with a more expensive and lessreactive metal. The diagram below shows anelectroplating cell that includes a battery connectedto a silver bar and a metal spoon. The bar and spoonare submerged in AgNO3(aq).

Explain the purpose of the battery in this cell.

Name DatePeriod


The diagram below represents an operating voltaic cellat 298 K and 1.0 atmosphere in a laboratoryinvestigation. The reaction occurring in the cell isrepresented by the balanced ionic equation below.

Write a balanced half-reaction equation for thereduction that occurs in this cell.


The diagram and balanced ionic equation below represent a voltaic cell with copper andsilver electrodes and the reaction that occurs when the cell is operating.

State the purpose of the salt bridge in this voltaic cell.

Name DatePeriod


Underground iron pipes in contact with moist soil are likely to corrode. This corrosion can be preventedby applying the principles of electrochemistry. Connecting an iron pipe to a magnesium block with a wirecreates an electrochemical cell. The magnesium block acts as the anode and the iron pipe acts as thecathode. A diagram of this system is shown below.

Explain, in terms of reactivity, why magnesium is preferred over zinc to protect underground iron pipes.Your response must include both magnesium and zinc.

Name DatePeriod

A) 0 B) 6 C) 8 D) 4 E) 10

1. How many electrons are needed to balance thehalf–reaction?

SO42– + 8 H+ + ? e– ®S2– + 4 H2O

A) anode, where oxidation occursB) anode, where reduction occursC) cathode, where oxidation occursD) cathode, where reduction occurs

2. In an electrolytic cell, the positive electrode is the

A) AgNO3 + NaCl ® AgCl + NaNO3

B) Cu + FeCl2 ® CuCl2 + FeC) Zn + 2 HCl ® ZnCl2 + H2

D) 2 Al + 3 Ni(NO3)2 ® 2 Al(NO3)3 + 3 Ni

3. For which chemical reaction must an electrolytic cell beused?

A) Cu2+ ions migrate toward the positive electrode.B) Cl– ions migrate toward the negative electrode.C) Cu2+ ions are reduced.D) Cl– ions are reduced.

4. Which occurs in an electrolytic cell containing CuCl2(aq)?

A) a chemical cell, because it is exothermicB) an electrolytic cell, because it is exothermicC) a chemical cell, because it is endothermicD) an electrolytic cell, because it is endothermic

5. Given the reaction:

2 H2O + electricity ® 2 H2 + O2

In which type of cell would this reaction most likelyoccur?

A) Ag0 + 1e– ® Ag+ B) Ag0 ® Ag+ + 1e–

C) Ag+ + 1e– ® Ag0 D) Ag+ ® Ag0 + 1e–

6. Which half-reaction occurs at the negative electrode inan electrolytic cell in which an object is being platedwith silver?

7. The diagram below represents an electrochemical cell.

A) Zn is reduced.B) Cu is oxidized.C) Electrons flow from Cu to Zn.D) Electrons flow from Zn to Cu.


8. Base your answer to the following question on thediagram below of an electrolytic cell in which theelectrodes are tin and copper.

A) anode and is positiveB) anode and is negativeC) cathode and is positiveD) cathode and is negative

In this electrolytic cell, electrode A is designated as the

Name DatePeriod

A) It produces electrical energy.B) It requires an external energy source.C) It uses radioactive nuclides.D) It undergoes a spontaneous redox reaction.

9. Which statement describes one characteristic of anoperating electrolytic cell?

10. Base your answer to the following question on thediagram below which represents the electroplating of ametal fork with Ag(s).

A) Ag+ + NO3– ® AgNO3

B) AgNO3 ® Ag+ + NO3–

C) Ag+ + e– ® Ag(s)D) Ag(s) ® Ag+ + e–

Which equation represents the half-reaction that takesplace at the fork?

A) chemical to electricalB) electrical to chemicalC) chemical to nuclearD) nuclear to chemical

11. Which energy change occurs in an operating voltaiccell?

A) Sn4+ ® Sn2+ + 2e–

B) Sn2+ ® Sn4+ + 2e–

C) Sn4+ + 2e– ® Sn2+

D) Sn2+ + 2e– ® Sn4+

E) Sn4+ + Sn2+ ® Sn6+ + 2e–

12. Which half–cell reaction correctly represents reduction?

A) Ag B) Zn C) Pb D) K

13. Which metal can be produced only by the electrolysisof its fused salt?

14. The diagram below shows a key being plated withcopper in an electrolytic cell

A) A, which is the anodeB) A, which is the cathodeC) B, which is the anodeD) B, which is the cathode

Given the reduction reaction for this cell:

Cu2+(aq) + 2e- ® Cu(s)

This reduction occurs at

A) (–), oxidationB) (+), oxidationC) (–), reductionD) (+), reductionE) no reaction occurs at the cathode

15. At the cathode during electrolysis, what is its chargeand what type of reaction occurs.

A) anode to the cathode through the wireB) cathode to the anode through the wireC) anode to the cathode through the salt bridgeD) cathode to the anode through the salt bridgeE) anode to the cathode through the wire and cathode

to the anode through the salt bridge

16. In an electrochemical cell, the electrons go from the

Name DatePeriod

A) neutralization B) esterificationC) electrolysis D) hydrolysis

17. The reaction 2 H2O ( ) ® 2 H2(g) + O2(g) is forced tooccur by use of an externally applied electric current.This procedure is called

A) in the wire B) at the anodeC) at the cathode D) at the salt bridgeE) in solution

18. Electroplating always takes place

A) 2 H2O( ) ® 2 H2(g) + O2(g)B) 2 HgO(s) ® 2 Hg( ) + O2(g)C) 2 KClO3( ) ® 2 KCl(s) + 3 O2(g)D) MgCO3(s) ® MgO(s) + CO2(s)

19. Which net reaction occurs by the process ofelectrolysis?

A) Anode: 2 Cl– ® Cl2 + 2e– Cathode: 2 Na+ +2e– ® 2 Na

B) Anode: 2 Cl– ® Cl2 + 2e– Cathode: 2 H2O + 2e– ® H2 + 2 OH–

C) Anode: 2 H2O ® O2 + 4 H+ + 4e– Cathode: 4Na+ + 4e– ® 4 Na

D) Anode: 2 H2O ® O2 + 4 H+ + 4e– Cathode: 4 H2O + 4e– ® 2 H2 + 4 OH–

E) Anode: Cl2 + 2e– ® 2 Cl– Cathode: 2 Na ® 2Na+ + 2e–

20. What are the anode and cathode half–reactions for theelectrolysis of fused (melted) NaCl?

A) Both occur at the anode.B) Both occur at the cathode.C) Oxidation occurs at the anode and reduction

occurs at the cathode.D) Oxidation occurs at the cathode and reduction

occurs at the anode.

21. Which statement is true about oxidation and reductionin an electrochemical cell?

22. A student wishes to set up an electrochemical cell. Thefollowing list of materials and equipment will be used:

• two 250-ml beakers• wire• one piece of Zn metal • 125 ml of 0.10 M Zn(NO3)2 • voltmeter • switch • one piece of Pb metal • 125 ml of 0.10 M Pb(NO3)2

A) an anodeB) a cathodeC) an external path for electronsD) a salt bridge

For the cell to operate properly, the student will alsoneed

A) 2 Cr(s) ® 2 Cr3+(aq) + 6e–

B) 3 Cu(s) ® 3 Cu2+(aq) + 6e–

C) 2 Cr3+(aq) + 6e– ® 2 Cr(s)D) 3 Cu2+(aq) + 6e– ® 3 Cu(s)E) It cannot be determined from the information

given

23. The net ionic reaction for an electrochemical cell is

2 Cr(s) + 3 Cu2+(aq) ®2 Cr3+(aq) + 3 Cu(s)

What is the reaction occurring at the cathode?

Name DatePeriod

A) Both Pb and Pb4+ undergo oxidation.B) Both Pb and Pb4+ undergo reduction.C) Pb is oxidized and Pb4+ is reduced.D) Neither the Pb nor the Pb4+ is oxidized or reduced.

24. What occurs during discharge in the lead-acid batteryreaction below?

Pb + PbO2 + 2 H2SO4 « 2 PbSO4 + 2 H2O

25. A diagram of a chemical cell and an equation are shownbelow.

A) the Pb(s) to the Cu(s)B) the Cu(s) to the Pb(s)C) the Pb2+(aq) to the Pb(s)D) the Cu2+(aq) to the Cu(s)

When the switch is closed, electrons will flow from

A) Cu anode to the Zn cathodeB) Cu cathode to the Zn anodeC) Zn anode to the Cu cathodeD) Zn cathode to the Cu anode

26. Given the balanced ionic equation representing thereaction in an operating voltaic cell: Zn(s) + Cu2+(aq) ® Zn2+(aq) + Cu(s)

The flow of electrons through the external circuit in thiscell is from the

27. Base your answer to the following question on thediagram of the chemical cell at 298 K and on theequation below.

A) gain electrons B) lose electronsC) gain protons D) lose protons

In the given reaction, the Ag+ ions

A) Na+ + 1e– ® Na0 B) Na0 ® Na+ + 1e–

C) 2 Cl– ® Cl20 + 2e– D) Cl20 + 2e– ® 2 Cl–

28. During the electrolysis of fused NaCl, whichhalf-reaction occurs at the negative electrode?

A) PbB) Pb2+

C) ZnD) Zn2+

E) It cannot be determined unless the potentials areknown.

29. To which electrode do the electrons move in the cell

Zn/Zn2+||Pb2+/Pb?

Name DatePeriod

30. A student collects the materials and equipment below toconstruct a voltaic cell:

• two 250-mL beakers• wire and a switch• one strip of magnesium• one strip of copper• 125 mL of 0.20 M Mg(NO3)2(aq)• 125 mL of 0.20 M Cu(NO3)2(aq)

A) an anode B) a batteryC) a cathode D) a salt bridge

Which additional item is required for the construction ofthe voltaic cell?

A) Sn2+ ® Sn4+ + 2e– B) Ag+ + e– ® AgC) Sn2+ + 2e– ® Sn4+ D) Ag+ ® Ag + e–

E) Sn2+ + Sn4+ ® 2e–

31. In the reaction

Sn2+(aq) + 2 Ag+(aq) ® Sn4+(aq) + 2 Ag(s)

What is the half–reaction equation for the oxidizingagent above?

32.

A) Cu2+ + 2e– ® Cu(s)B) Cu(s) ® Cu2+ + 2e–

C) 8 H+ + MnO4– + 5e– ® Mn2+ + 4 H2OD) Mn2+ + 4 H2O ® 8 H+ + MnO4– + 5e–

E) MnO4– + 8 H+ ® Mn2+ + 4 H2O

What is the oxidation half–reaction for the reaction? Cu + MnO4– + H+ ®Cu2+ + Mn2+ + H2O

A) increase the cell voltageB) maintain electrical neutralityC) increase the oxidation–reduction rateD) supply a travel pathway for electronsE) increase the rate of attainment of equilibrium

33. The function of the salt bridge in an electrochemicalcell is to

34. The diagram below shows the electrolysis of fused KCl.

A) Positive ions migrate toward the anode, where theylose electrons.

B) Positive ions migrate toward the anode, where theygain electrons.

C) Positive ions migrate toward the cathode, wherethey lose electrons.

D) Positive ions migrate toward the cathode, wherethey gain electrons.


A) light energy to chemical energyB) electrical energy to chemical energyC) chemical energy to light energyD) chemical energy to electrical energy

35. Which conversion of energy always occurs in a voltaiccell?

Name DatePeriod

36. The diagram below represents an operatingelectrochemical cell and the balanced ionic equation forthe reaction occurring in the cell.

A) Electrons flow through the salt bridge from theNi(s) to the Zn(s).

B) Electrons flow through the salt bridge from theZn(s) to the Ni(s).

C) Electrons flow through the wire from the Ni(s) tothe Zn(s).

D) Electrons flow through the wire from the Zn(s)to the Ni(s).

Which statement identifies the part of the cell thatconducts electrons and describes the direction ofelectron flow as the cell operates?

A) anode B) cathodeC) salt bridge D) external circuit

37. When a voltaic cell operates, ions move through the

A) Ag B) Ag+

C) Mg D) Mg2+

E) both Ag and Mg

38. The negative ions go to which electrode in the voltaiccell

Mg/Mg2+||Ag+/Ag?

39. Given the redox reaction:

A) B)C) D)

Which species is oxidized during discharge?

A) CaB) Ca2+

C) Cl–

D) Cl2

E) Oxidation does not occur

40. In the electrolysis of molten CaCl2 , the speciesoxidized is

41. Which statement best describes the key?

A) It acts as the cathode and is negative.B) It acts as the cathode and is positive.C) It acts as the anode and is negative.D) It acts as the anode and is positive.

Name DatePeriod

42. Consider the reaction,

S6+ + ? e– ® S2–

A) 6 B) 2 C) 8 D) 4 E) 10

How many electrons are needed to reduce S6+ to S2–?

43. The diagram below shows a spoon that will beelectroplated with nickel metal.

A) The spoon will lose mass, and the Ni(s) will bereduced.

B) The spoon will lose mass, and the Ni(s) will beoxidized.

C) The spoon will gain mass, and the Ni(s) will bereduced.

D) The spoon will gain mass, and the Ni(s) will beoxidized.

What will occur when switch S is closed?

44. Which is the cathode of this electrochemical cell?

Cr + Au3+ ® Cr3+ + Au

A) CrB) Au3+

C) Cr3+

D) AuE) It cannot be determined unless the potentials are

known

A) anode to the cathode through the wireB) cathode to the anode through the wireC) anode to the cathode through the salt bridgeD) cathode to the anode through the salt bridgeE) cathode to the anode through the wire and anode to

the cathode through the salt bridge

45. In an electrochemical cell, the positive ions go from the

A) The reaction occurs in a chemical cell and releasesenergy.

B) The reaction occurs in a chemical cell and absorbsenergy.

C) The reaction occurs in an electrolytic cell andreleases energy.

D) The reaction occurs in an electrolytic cell andabsorbs energy.

46. Which statement best describes the reaction representedby the equation below?

2 NaCl + 2 H2O + electricity ® Cl2 + H2 + 2NaOH

Name DatePeriod

47. Base your answer to the following question on the diagram of the voltaic cell below.

When the switch is closed, in which half-cell does oxidation occur?

48. Base your answer to the following question on the diagram and balanced equation below, which representthe electrolysis of molten NaCl.

Write the balanced half-reaction for the reduction that occurs in this electrolytic cell.

Name DatePeriod


A voltaic cell with magnesium and copper electrodes is shown in the diagram below. The copperelectrode has a mass of 15.0 grams.

When the switch is closed, the reaction in the cell begins. The balanced ionic equation for thereaction in the cell is shown below the cell diagram. After several hours, the copper electrode isremoved, rinsed with water, and dried. At this time, the mass of the copper electrode is greater than15.0 grams.

Explain, in terms of copper ions and copper atoms, why the mass of the copper electrode increases as thecell operates. Your response must include information about both copper ions and copper atoms.

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50. Base your answer to the following question on the information below. The diagram below represents an operating electrolytic cell used to plate silver onto a nickel key. Asthe cell operates, oxidation occurs at the silver electrode and the mass of the silver electrode decreases.

Explain, in terms of Ag atoms and Ag+(aq) ions, why the mass of the silver electrode decreases as the celloperates.

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A student places a 2.50-gram sample ofmagnesium metal in a bottle and fits the bottle witha 2-hole stopper as shown in the diagram.Hydrochloric acid is added to the bottle, causing areaction. As the reaction proceeds, hydrogen gastravels through the tubing to an inverted bottle filledwith water, displacing some of the water in thebottle.

Based on Reference Table J, explain why Ag(s) will not react with HCl (aq) to generate H2(g).


Electroplating is an electrolytic process used to coatmetal objects with a more expensive and lessreactive metal. The diagram below shows anelectroplating cell that includes a battery connectedto a silver bar and a metal spoon. The bar and spoonare submerged in AgNO3(aq).

Explain the purpose of the battery in this cell.

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The diagram below represents an operating voltaic cellat 298 K and 1.0 atmosphere in a laboratoryinvestigation. The reaction occurring in the cell isrepresented by the balanced ionic equation below.

Write a balanced half-reaction equation for thereduction that occurs in this cell.


The diagram and balanced ionic equation below represent a voltaic cell with copper andsilver electrodes and the reaction that occurs when the cell is operating.

State the purpose of the salt bridge in this voltaic cell.

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Underground iron pipes in contact with moist soil are likely to corrode. This corrosion can be preventedby applying the principles of electrochemistry. Connecting an iron pipe to a magnesium block with a wirecreates an electrochemical cell. The magnesium block acts as the anode and the iron pipe acts as thecathode. A diagram of this system is shown below.

Explain, in terms of reactivity, why magnesium is preferred over zinc to protect underground iron pipes.Your response must include both magnesium and zinc.

Answer Keyelectrochemistry

1. C2. A3. B4. C5. D6. C7. D8. A9. B10. C11. A12. C13. D14. B15. C16. A17. C18. C19. A20. A21. C22. D23. D24. C25. A26. C27. A28. A29. A30. D31. B32. B33. B34. D35. D36. D

37. C38. C39. A40. C41. A42. C43. D44. D45. C46. D47. Acceptable responses:

half-cell 1, Pb, left,lead.

48. • Na+ + e- Na or2Na+ + 2e- 2Na

49. copper ions from thesolution are reducedto copper atoms at theelectrode, increasingthe mass of theelectrode; Copperions become copperatoms; The number ofcopper ions decreases,and the number ofcopper atomsincreases.

50. —Silver atoms loseelectrons and becomesilver ions in thesolution. —Some ofthe Ag atoms becomeAg+ ions. —Silveratoms are oxidized tosilver ions.

51. Examples: – Ag isbelow H2 in theactivity series. – Ag ismore difficult tooxidize.

52. Examples: – Thebattery provides theelectrical energynecessary for thereaction to occur.

53. Ag+ + e- ® Ag or 2Ag+ + 2e- ® 2Ag

54. Acceptable responsesinclude, but are notlimited to: • The saltbridge allows for themigration of ionsbetween thehalf-cells. • The saltbridge preventspolarization of thehalf-cells maintainselectrical neutrality

55. Examples: – Magnesium atomslose electrons moreeasily than zincatoms. – Mg oxidizesmore readily than Zn. – Mg is more activethan Zn.

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