organic chemistry

Cards (15)

  • Crude oil is a mixture of hydrocarbons, which are long chains of hydrogen and carbon atoms.
  • alkanes are saturated hydrocarbons, they contain C-C and C-H bonds only, they are apart of the same homologous series as they have the same general formula and properties
  • Alkanes follow the general formula CnH2n+2
  • Properties of long chain hydrocarbons -
    • high viscosity
  • properties of long chain hydrocarbons -
    • high viscosity
    • low volatility
    • low flammability
    • high boiling point
  • properties of short chain hydrocarbons -
    • low viscosity
    • high volatility
    • high flammability
    • low boiling point
  • HydroCarbons can be broken down (cracked) to produce smaller, more useful molecules
  • Catalytic cracking - cheaper
    • Zeolite catalyst (contains Aluminium Oxide)
    • Temperature of 500 degrees Centigrade
  • Steam cracking
    • no catalyst
    • higher temperature (750 degrees Centigrade)
  • when cracking occurs a long chain alkane is thermally decomposed into a mixture of shorter alkanes and alkenes
  • alkenes are unsaturated as they contain a C=C bond
  • Polymers (plastics) - long molecules of repeating monomers (small molecules)
  • Fractional distillation
    • heat crude oil to a vapour
    • vapours enter column at the bottom and separate by boiling point
    • the column is coolest at the top, and hottest at the bottom
    • fractions (hydrocarbons) condense at different temperatures
    • shorter fractions condense towards the top due to their lower boiling point
  • Alkene + Bromine turns colourless, Alkenes react with Bromine because of their double Carbon bond
  • Alkane + Bromine stays orange