Electricity:

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Electricity

• The transfer or movement of electrons.

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Electrochemistry

• conversion of chemical energy into electrical
  energy or vice versa.
• Galvanic (voltaic) spontaneous
• Electrolytic non-spontaneous

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• Redox
• ZnCuSO4?ZnSO4 Cu

• Zn ? Zn2 2e-

• Cu2 2e- ? Cu

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Electrochemical Cell

• device that uses redox reactions to produce or
  use electricity.

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Voltaic Cell

• an electrochemical cell where spontaneous redox
  reactions produce electricity.

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Electrodes

• a metal or graphite surface on which oxidation or
  reduction can occur.

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Anode

• electrode at which oxidation occurs.
• negative electrode

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Cathode

• electrode at which reduction occurs.
• positive electrode

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Half-Cell

• Container in which a half reaction of a redox
  reaction occurs.

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Salt Bridge

• a tube of an electrolyte solution that connects
  two voltaic half-cells.
• It allows ions to move between compartments
  without mixing solutions

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Cell Potential (Ecell )

• difference in electric potential energy between
  2 electrodes of a voltaic cell.

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Voltage (volts)

• units for cell potential

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Electrode Potential

• Reduction potential is tendency for a substance
  to gain electrons at the cathode.
• Oxidation potential is the tendency to lose
  electrons at the anode.

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Standard Cell Potential Ecell

• Standard conditions
• ion 1 M
• P 1 atm.
• T 25C

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Cell Potential (Ecell )

• Sum of electrode potentials
• Ecell Eox Ered

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Problem (See p.667)

• Calculate Ecell produced by a voltaic cell with
  a nickel electrode in Ni2 solution and a silver
  electrode in solution of Ag ions.

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Problem

• Calculate the voltage produced by a voltaic cell
  with an Al electrode in Al3 solution and an iron
  electrode in a solution of Fe2 ions.

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• Abbreviated form
• ZnCuSO4?ZnSO4 Cu
• Zn ? Zn2 2e-
• Cu2 2e- ? Cu
• Zn Zn2 Cu2 Cu

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Electrolysis

• Use of electrical energy to bring about a
  chemical reaction.

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Electrolytic Cell

• an electrochemical cell where electrical energy
  drives nonspontaneous reactions.

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Electroplating

• depositing one metal on another by use of
  electric current.