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Electrochemistry Lesson 1 Introduction
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Electrochemistry Is the study of reactions that gain or lose electrons.
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Electrochemistry Is the study of reactions that gain or lose electrons. In this unit we will study:
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Battery Reactions- oxidation and reduction
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Corrosion- oxidation
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Preventing Corrosion
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Oxidation
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Electroplating- reduction
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Refining Metals- reduction
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Oxidation means loss of electrons
LEO LossElectronsOxidation Oxidation Half Reactions show how Metals or Anions lose electrons +1 Balance charge Add electron to most positive side Na → Na+ + 1e- metal ion Oxidation- electrons are on the right
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Oxidation means loss of electrons
LEO LossElectronsOxidation Oxidation Half Reactions show how Metals or Anions lose electrons +3 Balance charge Add electrons to most positive side Al → Al3+ + 3e- metal ion Oxidation- electrons are on the right
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Oxidation means loss of electrons
LEO LossElectronsOxidation Oxidation Half Reactions show how Metals or Anions lose electrons O2- → 2 O2 + 4e- Balance for numbers anion atom Balance charge Add electrons to most positive side Oxidation- electrons are on the right
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Reduction means gain of electrons
GER GainElectronsReduction Reduction Half Reactions show how Nonmetals or Cations gain electrons 3+ Balance charge Add electrons to most positive side Ga3+ + 3e- → Ga cation atom Reduction- electrons are on the left
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Reduction means gain of electrons
GER GainElectronsReduction Reduction Half Reactions show how Nonmetals or Cations gain electrons N2 + 6e- → 2 N3- Reduction- electrons are on the left
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Balance each simple half reaction
1. Ca → Ca2+ + 2e- oxidation 2. F2 + 2e- → 2F- reduction 3. O2 + 4e- → O2- reduction 4. Ga → Ga3+ + 3e- oxidation 5. 2Br - → Br e oxidation 6. Li+ + e- → Li reduction
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Redox Reactions Both oxidation and reduction must occur. The electrons gained equals the electrons lost. 1. Al + Zn(NO3)2 2 ( ) oxidation Al → Al3+ + 3e- 3 ( ) reduction Zn2+ + 2e- → Zn 2Al + 3Zn2+ → 2Al Zn redox
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2. Cl2 + Na Cl2 + 2e- → 2Cl- reduction 2(Na → Na+ + 1e-) oxidation Cl Na → 2Cl Na+ redox
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Oxidizing Agents cause oxidation by undergoing reduction.
They gain electrons. Nonmetals and cations are oxidizing agents because they gain electrons. Cl2 Ca2+ F2 Na+ Cl2 + 2e- → 2Cl- Ca e- → Ca Both can gain electrons
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Reducing Agents cause reduction by undergoing oxidation.
They lose electrons. Metals and anions are reducing agents because they lose electrons. N3- Al O2- Li 2N3- → N2 + 6e- Al → Al3+ + 3e- Both can lose electrons
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You need to be able to tell an oxidizing agent from a reducing agent.
Circle each oxidizing agent. They can reduce or gain electrons Ga Rb+ I- P4 Fe Co2+ S I2 Cu Pb2+ Li Br-
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Label each reactant as an oxidizing or reducing agent.
2Ag+ + Pb → 2Ag Pb2+ Gaining electrons Losing electrons Reduction Oxidation Ox Agent Red Agent
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Label each reactant as an oxidizing or reducing agent.
6I Al3+ → 3I2 + 2Al Losing electrons Gaining electrons Oxidation Reduction Red Agent Ox Agent
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