Electrolysis

• What is electricity?

  Flow of electrons

  • travels in one direction
• Electricity conduction

  • Metals: all
  • Non-metals: carbon (graphite)
• Conduction: solid state

  Solid compounds never conduct

  • no delocalized electrons/moving ions
  • eg: ionic & covalent
• Can/Cant's conduct electricity

  Can:

  • All metals
  • Carbon (graphite)
  • Ionic compound in solution
  • Ionic compound molten form

  Can't:

  • Covalent compound
  • Solid ionic compound
• Conduction: liquid state

  Solid compounds --> liquid:

  • melting
  • or dissolve
  • dissociation (dissolved but for ionic)
• Ionic comps conducting elec

  • Cathode (+) = attracts cations
  • Anode (-) = attracts anions
  • Anode = oxidized
  • Cathode = reduced

  When H2O present:

  • H+ and OH- will be attracted accordingly
• Electrolysis uses

  • Seperate ions in solution/molten
  • Purification
  • Electroplating
• Purity decrease = Resistance increase
• Refining/Purifying metals

  Electrolyte MUST contain soluble metal:

  • Eg: Copper nitrate - non copper sinks
  • Only metal same w/ electrolyte can move
• Electroplating

  • Same steps
  • Results diff: obj covered by metal