CHM 2046C                                       Name: ________________

Module 14 Paper and Pencil Homework Packet

 Module Fourteen: Electrochemistry Jespersen  Chapter 19 Possible Actual 1 1 E.   Cell Potentials and Free Energy Section 19.4 1 F. The Nernst Equation Calculation Section 19.5 1 G. Electrochemical Determination of pH Section 17.1 0 Answers 1 I. Batteries, Fuel Cells, Electrolysis Section 19.6 1 1 1 Module Fourteen Total: 8

Part C: Cell Basics                                                        1 point Match the following:

____1. Anode

____2. Cathode

____3. Direction of Electron Flow

____4. Anion Flow

____5. Cation Flow

____6. Negative Charged

____7. Positive Charged (Circle One)

____8. Site of Oxidation

____9. Site of Reduction

_______10. Salt Bridge: CuSO4, ZnSO4 or Na2SO4 (or Circle One)

Reaction at Anode:    ________________________________

Reaction at Cathode: _________________________________

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Part D: Shorthand Notation for Galvanic Cells            1 point

For the following Galvanic Cell: 1. Write the Shorthand notation for the above voltaic cell:

2. Write a balanced equation for the cell reaction:

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Part E: Calculating Standard Cell Potentials            1 point 1. The standard potential for the following galvanic cell is 0.92 V:

Al(s) | Al3+ (aq) || Cr3+ (aq) | Cr (s)

Show the Anode Reaction, Cathode Reaction, Overall Cell Reaction then using the above table look up the standard reduction potential for Al3+ /Al(s) half cell and calculate the standard reduction potential for the Cr3+/Cr half cell:

Anode Reaction:                                                        Eo =

Cathode Reaction:                                                    Eo =

--------------------------------------------------------------------

Overall Reaction:                                                       Eo =

2. Using the above table, calculate overall cell potential for the following cell:

Pt(s) | H2 (1 atm) | H1+ (1 M) || Cu2+ (1 M) | Cu (s)

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Part F: Calculating Cell Potentials using the Nernst Equation

1 point

Nernst Equation:

E = Eo – RT/nF [ln Q]        or         E = Eo - 2.303RT/nF [log Q]

Or E = Eo – 0.0592 V/n [log Q]      in volts at 25oC

Worked Example 17.6 Page 5: Module 14 Paper and Pencil Homework Packet

Part G: Electrochemical Determination of pH  0 points

Nernst Equation:

E = Eo – RT/nF [ln Q]        or         E = Eo - 2.303RT/nF [log Q]

Or E = Eo – 0.0592 V/n [log Q]      in volts at 25oC

Standard Cell Potential and the Equilibrium Constant:

Eo =0.0593 V/n [log K] in volts at 25oC

Worked Example 17.8 Skip

Page 6: Module 14 Paper and Pencil Homework Packet

Part H: Standard Cell Potentials and Equilibrium Constants

1 points

Nernst Equation:

E = Eo – RT/nF [ln Q]        or         E = Eo - 2.303RT/nF [log Q]

Or E = Eo – 0.0592 V/n [log Q]      in volts at 25oC

Standard Cell Potential and the Equilibrium Constant:

Eo =0.0593 V/n [log K] in volts at 25oC

R = 8.31451 J / K∙mol  F = Faraday Constant = 9.6485309 x 104 J/V∙mol

Worked Example 19.7 p925 Page 7: Module 14 Paper and Pencil Homework Packet

Part I: Batteries, Fuel Cell, Electrolysis                    1 point

Dry Cell Battery                                 Mercury Battery  Match the following:

Dry Cell                                           Mercury Cell

____1. Cathode                                       ______11. Cathode

____2. Anode                                ______12. Anode

____3. Zinc Can                                      ______13. Outer Steel Case

____4. Carbon Rod                      ______14. Steel Cover Top

____5. Porous Separator            ______15. Tin-Plated Inner Top

____6. Wax seal                                      ______16. Sealing and Insulated

____7. Steel Cover                        ______17. Zn

____8. Sand Cushion                            ______18. KOH saturated with

ZnO in absorbent Material (electrolyte)

____9. NH4Cl, ZnCl2, MnO2 paste        ______19. HgO mixed with

Graphite

____10. Insulating Washer                   ______20. Barrier

Reaction at Anode:    ______________        _________________

Reaction at Cathode: ______________        _________________

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Part J: Chapter 19 Discussion Questions  1 point

1. Which electrode is the anode and which electrode is the cathode in an electrochemical cell?

2. What is a salt bridge? Why is such a device necessary?

3. What is the difference between a primary cell and a secondary cell?

4. What is the relationship between charge, potential, and energy?

5. What is the standard electrode?  What is a standard electrode-reduction potential? What is its symbol?

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Part K: Chapter 19 Key Terms            1 point

1. ______________– the electrode at which oxidation takes place

2. ______________ the electrode at which reduction takes place

3. ______________ a technique for protecting a metal from corrosion by converting it to a second metal that is more easily oxidized

4. ______________ same as electromotive force

5. ______________the oxidative deterioration of a metal, such as the conversion of iron to rust

6. ______________a devise for interconverting chemical and electrical energy

7..  ______________ – the area of chemistry concerned with the interconversion of chemical and electrical energy

8. ______________a substance that dissolves in water to produce ions

9.  ______________ – the process of using an electric current to bring about chemical change

10. ______________ – the electrical potential that pushes electrons away from the anode and pulls them toward the cathode

11. ______________the coating of one metal on the surface of another using electrolysis

12. ______________the purification of a metal by means of electrolysis

13. ______________ the elctric charge on 1 mol of electrons

14. ______________a galvanic cell in which one of the reactants is a traditional fuel such as methane or hydrogen

15. ______________ An electrochemical cell in which a spontaneous chemical reaction generates an electric current

16. ______________a process for protecting steel from corrosion by coating it with zinc

17. ______________ The oxidation or reduction part of a redox reaction

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Park K Continued

18. ______________ the commercial method for protecting aluminum by electrolysis of a molten mixture of aluminum oxide and cryolite

19. ______________ An equation for calculating cell potentials under non-standard state conditions

20. ______________An additional voltage required above the calculated for an electrolysis reaction

21. ______________ A tube that contains a gel permeated with a solution of an inert electrolyte connecting the two sides of an electrochemical cell.

22. ______________The cell potential when both reactants and products are in their saturated states

23. ______________ same as standard reduction potential

24. ______________ A reference half cell consisting of a platinum electrode in contact with H2 gas  and aqueous H1+ ions at standard state conditions

25. ______________ The standard potential for a reduction half cell