Fractional distillation

• What is crude oil formed from?


  The remains of plants and animals, mainly plankton, that died millions of years ago and were buried in mud. Over millions f years, with high temperature and pressure, the remains turn to crude oil, which can be drilled up from the rocks where it is found
• What is a disadvantage of fossil fuels


  They are non renewable and finite
• What is crude oil made of?


  A mixture of lots of different hydrocarbons, most of which are alkanes. They are separated by fractional distillation
• Describe the fractional distillation process

  1. Oil heated until most turns into gas. enters fractionating column (liquid drained off). 2.in column - temperature gradient (hot at bottom & cool as go up).3.longer hydrocarbons = higher boiling points. condense back into liquids & drain out of column early on, near bottom. Shorter hydrocarbons = lower boiling points, condense & drain later, near top where it’s cooler.4. crude oil separated into different fractions. Each fraction contains mix of hydrocarbons. all contain similar number of carbon atoms, so have similar boiling points
• What are 4 fuels made from crude oil

  • Petrol
  • kerosene
  • diesel
  • heavy fuel oil