cracking & alkenes

• what is cracking?

  when large hydrocarbons are broken down into smaller, more useful molecules
• what are two methods of cracking?

  • catalytic cracking
  • steam cracking
• conditions for catalytic cracking?

  • heat hydrocarbons to a vapour
  • pass vapour over hot powdered aluminium oxide catalyst
• conditions for steam cracking?

  • heat hydrocarbons to a vapour
  • mix w steam
  • heat to a high temperature
• what are the products of cracking?

  • alkanes
  • alkenes
• difference between alkenes & alkanes

  alkenes are more reactive than alkanes
• why is it important to crack long-chain hydrocarbon fractions?

  • high demand for short chain - flammable so make good fuels
  • alkenes used to make polymers