1. Electrochemistry Lesson 1 Introduction

2. Electrochemistry: the conversion of chemical energy into electrical energy and vice versa. (the study of reactions that gain or lose electrons) In this unit we will study:

3. Battery Reactions- oxidation and reduction

4. Corrosion- oxidation

5. Preventing Corrosion

6. Oxidation

7. Refining Metals- reduction

8. Oxidation & Reduction

9. Oxidation means loss of electrons LEOLossElectronsOxidation Oxidation Half Reactions show how Metals or Anions lose electrons metalion Balance charge Add electron to most positive side Oxidation- electrons are on the right Na→ 0+1 +1e - Na +

10. Oxidation means loss of electrons LEOLossElectronsOxidation Oxidation Half Reactions show how Metals or Anions lose electrons metalion Balance charge Add electrons to most positive side Oxidation- electrons are on the right Al→ 0+3 Al 3+ +3e -

11. Oxidation means loss of electrons LEOLossElectronsOxidation Oxidation Half Reactions show how Metals or Anions lose electrons O 2- → anionatom Balance for numbers Oxidation- electrons are on the right Balance charge Add electrons to most positive side O2O2 2+4e -

12. Reduction

13. Reduction means gain of electrons GERGainElectronsReduction Reduction Half Reactions show how Nonmetals or Cations gain electrons cationatom Balance charge Add electrons to most positive side Reduction- electrons are on the left 3+ 0 →Ga+ 3e - Ga 3+

14. Reduction means gain of electrons GERGainElectronsReduction Reduction Half Reactions show how Nonmetals or Cations gain electrons N2N2 N 3- 2+ 6e - → Reduction- electrons are on the left

15. Balance each simple half reaction 1. → Ca 2+ +2e - Caoxidation 2.F 2 + 2e - → 2F - reduction 3.O 2 + 4e - → 2O 2- reduction 4.Ga→ Ga 3+ +3e - oxidation 5.2Br - → Br 2 + 2e - oxidation 6.Li + +e - → Lireduction

16. Oxidation Vs Reduction Oxidation Reduction Loss of electrons Charge becomes more positive Metals and anions Electrons on outside/product side Gain of electrons Charge becomes less positive Non Metals and cations Electrons on reactant side

17. Redox Reactions Both oxidation and reduction must occur.

18. Redox Reactions Both oxidation and reduction must occur. The electrons gained equals the electrons lost 1.Cl 2 +Na Cl 2 reduction Na oxidation

19. Redox Reactions Both oxidation and reduction must occur. The electrons gained equals the electrons lost. 2.Al+Zn +2 Al →Al 3+ +3e - ( )oxidation Zn 2+ ( ) reduction 2 3 2Al + 3Zn 2+ → 2Al 3+ + 3Zn redox +2e - →Zn

20. Oxidizing & Reducing Agents

21. Oxidizing Agents cause oxidation by undergoing reduction. They gain electrons. Nonmetals and cations are oxidizing agents Cl 2 Ca 2+ F 2 Na + Cl 2 +2e - →2Cl - Ca 2+ +2e - →Ca Both can gain electrons

22. Reducing Agents cause reduction by undergoing oxidation. They lose electrons. Metals and anions are reducing agents N 3- AlO 2- Li 2N 3- →N 2 +6e - Al→Al 3+ +3e - Both can lose electrons

23. You need to be able to tell an oxidizing agent from a reducing agent. TRY: Circle each oxidizing agent. They are reduced or gain electrons GaRb + I - P 4 FeCo 2+ SI 2 CuPb 2+ LiBr -

24. Label each reactant as an oxidizing or reducing agent. 2Ag + +Pb→2Ag +Pb 2+ Gaining electrons ReductionOxidation Losing electrons Oxidizing Agent Reducing Agent

25. TRY: Label each reactant as an oxidizing or reducing agent. 6I - + 2Al 3+ →3I 2 +2Al Gaining electronsLosing electrons Oxidation Red Agent Reduction Ox Agent

26. Homework Page192 Question#1 and #2