Organic Chem

• Hydrocarbon: a substance that contains hydrogen and carbon atoms only.

  Main source = crude oil.
• Fractional Distillation

  • Vaporized crude oil enters fractioning tower
  • Hydrocarbons cool as they rise up and condense at different heights as they have different boiling points.
• Hydrocarbons (highest to lowest):

  • Refinery gas for bottled gases.
  • Petrol for car fuel.
  • Naptha for manufacture of chemicals and plastics.
  • Kerosene for aircraft fuel.
  • Diesel as fuel for cars and trains.
  • Fuel oils used as ships fuel.
  • Bitumen to surface roads and roofs.
• Cracking: Breakdown of larger saturated hydrocarbons into smaller more useful ones.

  Can be carried out by heating (thermal decomposition)
• Homologous series

  Group of organic compounds which:

  • Have same general formula
  • Show similar chemical properties
  • Differ by a CH2 unit
• Alkanes:

  General Formula = CnH2n+2

  • Methane - CH4
  • Ethane - C2H6
  • Propane - C3H8
  • Butane - C4H10
• Alkenes

  General Formula = CnH2n

  • Ethene - C2H4
  • Propene- C3H6
  • But-1-ene - C4H8
  • But-2-ene - C4H8
• Complete combustion: occurs in plentiful supply of oxygen.

  Incomplete combustion: occurs in limited oxygen.
• Alkanes and Alkenes in water:

  • 2 layers form
  • Immiscible (dont mix)
• Alkanes Burning:

  • Orange flame
  • Some soot

  Alkenes:

  • orange flame
  • produce more soot when burned.
• Bromine water:

  Alkanes - stays orange.

  Alkenes - turns colourless.
• We use bromine water to distinguish between alkanes and alkenes.
• Polymerization: Creating a long chain molecule from small molecules.
• Addition polymerization: Joining monomer molecules together to form long chain molecule (polymer).
• Uses for Polymers:

  Polythene - Cheap, strong, easily moulded

  • Plastic bags
  • Bottles
  • Buckets

  Polychloroethe/PVC - Hard but flexible

  • Electric wire
  • Insulation
  • Plastic sheets