CO6

• Electrochemistry

  study and use of e- flow in chemical reactions
• Redox Reaction

  generate (and use) e-

  Those e- can be harnessed (batteries)

  Corrosion is an electrochemical reaction.
• Reduction

  gain of e-

  decrease in ox. no.
• Oxidation

  loss of e-

  increase in ox. no
• Electrochemical Cells

  Linked oxidation and reduction reactions

  e- move across an external conductor

  voltaic cell or a battery
• Battery

  strictly a series of linked voltaic cells
• Electrodes

  anode and cathodes

  Allow e- to pass in and out of solution

  A salt bridge (or porous barrier) is required
• Salt bridge

  Contains a salt solution

  Ions pass into the cells (restricts bulk flow)

  Stops charge buildup
• Compact Notation

  Current flows from anode to cathode

  | = phase boundary

  || = salt bridge
• Primary battery

  One time use

  Not easily rechargeable
• Secondary battery

  Rechargeable battery
• Fuel Cells

  Convert bond energy directly into electricity
• Proton-Exchange Membrane (PEM) fuel cell

  Graphite electrodes

  Pt catalyst coated on both sides of the membrane