Chapter 1: Introduction

• Redox reactions and energetics

  • Example of redox reaction: zinc metal + copper 2 ion -> zinc ion + copper metal

  • Spontaneity of reaction: proceeds to completion, spontaneous in forward direction

  • Standard free energies of reactants and products

    • Zinc and copper metals: 0 kJ/mol

    • Copper 2 ion: +65 kJ/mol

    • Zinc ion: -147 kJ/mol

  • Calculation of standard free energy: -212 kJ/mol, indicating a spontaneous reaction

• Spontaneous redox reaction between zinc and copper

  • Zinc strip in copper 2 nitrate solution leads to deposition of copper onto zinc and dissolution of zinc into zinc ions

  • Process continues until enough copper coats zinc to prevent zinc ions from escaping into solution

  • Reaction has enthalpy (delta H) negative, releasing energy as heat

  • Chemical energy can be captured as electrical energy

Chapter 2: Copper And Zinc

• Voltaic cells for separating redox reactions

  • Voltaic cells: spontaneous, used to perform electrical work

  • Galvanic cells: non-spontaneous, require external energy

• Components and operation of a voltaic cell

  • Electrochemical cell with zinc and copper electrodes

  • Connection through wire, switch, and voltmeter

  • Salt bridge for ion movement

  • Potential energy difference measured as voltage

• Rules of voltaic cells

  • Anode: where oxidation occurs, electrons are products

  • Cathode: where reduction occurs, electrodes are reagents

  • Electrons flow through wire, cannot swim

Chapter 3: Energy Of Electrons

• Electrons flow through wires, not solution, to maintain energy and do work

  • Exceptions like solvated electrons in liquid ammonia at -40 degrees C

• Electrons flow from anode to cathode in voltaic cell

• Anode is negative, cathode is positive, electrons flow through wire

• Voltage is proportional to free energy of reaction, allowing creation of different voltage batteries

• Anode compartment for oxidation, cathode compartment for reduction

• Anions and cations move through porous barrier or salt bridge in batteries

Chapter 4: Solvated Zinc Ion

• Cations move into cathode compartment, anions move into anode compartment for charge compensation

• Zinc ions in anode compartment neutralized by moving nitrate ions

• Process of zinc metal and copper ion solution interaction

• Zinc atom transfers electrons to copper ion, forming solvated zinc ion

• Half reactions in anode and cathode compartments

Chapter 5: Conclusion

• Hydrogen fuel cell reaction: 2 hydrogen molecules oxidized to 2 hydrogen ions and 4 electrons

• Electrons unite with oxygen at cathode to produce water

• Proton conducting membrane allows hydrogen ions to move to cathode

• Fuel cell more efficient in producing work compared to burning hydrogen

• Fuel cell eliminates most energy losses, promising efficiency in