Electrochemistry Lesson 1 Introduction

Electrochemistry Is the study of reactions that gain or lose electrons.

Electrochemistry Is the study of reactions that gain or lose electrons. In this unit we will study:

Battery Reactions- oxidation and reduction

Corrosion- oxidation

Preventing Corrosion

Oxidation

Electroplating- reduction

Refining Metals- reduction

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→ e - Na +

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 -

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 -

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+

Reduction means gain of electrons GERGainElectronsReduction Reduction Half Reactions show how Nonmetals or Cations gain electrons N2N2 N e - → Reduction- electrons are on the left

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

Redox Reactions Both oxidation and reduction must occur. The electrons gained equals the electrons lost. 1.Al+Zn(NO 3 ) 2 Al →Al 3+ +3e - ( )oxidation Zn 2+ ( ) reduction 2 3 2Al + 3Zn 2+ → 2Al Zn redox +2e - →Zn

2.Cl 2 +Na Cl 2 +2e - →2Cl - reduction 2(Na →Na + +1e - )oxidation Cl 2 + 2Na → 2Cl - + 2Na + redox

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

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

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

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

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