Fractional distillation

• What is the main technique used to separate hydrocarbons in crude oil?

  Fractional distillation
• Why do longer chain hydrocarbons have higher boiling points?

  They have stronger intermolecular forces
• What do fractions in fractional distillation contain?

  Hydrocarbons with similar carbon atoms
• What are the stages of fractional distillation?

  1. Heat crude oil to high temperature
  2. Crude oil boils and evaporates
  3. Vapor enters fractional distillation column
  4. Column is hotter at the bottom, cooler at the top
  5. Hydrocarbon vapors rise and condense at boiling points
  6. Liquid fractions are removed
  7. Remaining hydrocarbons continue to rise and condense
• Where does fractional distillation take place?

  In large columns at oil refineries
• What happens to hydrocarbons when they reach their boiling point in the column?

  They condense back to a liquid
• How are very long chain hydrocarbons removed from the column?

  From the bottom of the column
• How are very short chain hydrocarbons removed from the column?

  As gases from the top of the column
• What are some uses of the fractions produced by fractional distillation?

  • Petrol and Diesel: fuel for cars
  • Kerosene: jet fuel
  • Heavy fuel oil: powers ships
  • Liquefied petroleum gas: used in camping stoves
• What is meant by the term 'feed stock' in the petrochemical industry?

  A chemical used to make other chemicals
• What are some products made from feed stock fractions?

  • Solvents
  • Lubricants
  • Detergents
  • Polymers
• Where can students find more questions on fractional distillation?

  In the vision workbook