Crude Oil and Fuels

HideShow resource information
View mindmap
  • Crude Oil & Fuels
    • Hydrocarbons
      • Most of the compounds in crude oil are called hydrocarbons.
        • Many of these hydrocarbons are alkanes
          • CnH(2n+2)
          • Alkanes contain as many hydrogen atoms as possible in each molecule so we call the saturated.
          • CH4 (methane)
          • C2H6 (ethene)
          • C3H8 (propane)
          • C4H10 (butane)
          • C5H12 (pentane)
      • We can represent molecules by a displayed formula that shows how the atoms are bonded together.
    • Fractional Distillation
      • Crude oil is separate into fractions (the liquids that boil within different temp ranges) using fractional distillation.
        • This can be done because the boiling point of a hydrocarbon depends on the size of its molecules.
          • The larger the hydrocarbon molecules, the higher the boiling point.
      • 1. The CO is vaporised and fed into the column.
      • 2. The vapours move up the column getting cooler as the go up.
      • 3. The HC condense to liquids when the reach their boiling point.
      • HC with small molecules have the lowest boiling points so are collected at the top.
      • Low BP = low viscosity. They are also flammble and burn with clean flames so very useful
    • Burning Fuels
      • Burning any fuel that contains carbon producs CO2.
        • cause of global warming
      • when pure hydrocarbons burn completely they are oxidised to COS and H20
        • eg; propane+oxygen = carbon dioxide+water
        • however, the fuels arent always burned completely: incomplete combustion. (a limited supply of air CO - toxic)
          • carbon may also be producedso solid particles that contain soot and unburned hydrocarons called particulates can be produced.
          • global dimming.
    • Alternative Fuels
      • Biofuels are made from plant or animal products and are renewable.
      • Biodiesel can be made from vegetable oils extracted from plants
        • Advantages: makes little contribution to CO2 levels.
        • Disadvantages: the plants grown for biodiesel use large areas of farmland.
      • Ethanol made from sugar cane is a biofuel
        • liquid so canbe sored and distributed like other liquid fuels.
          • can be mixwed with petrol.
      • Using hydrogen as a fuel had advantage that it produces only water when it is burned (2H2 +O2 = 2H20)
        • its a gas so takes up a large volume. Difficult to store in the quantities needed for combustion.
        • it can be produced from water by electrolysis but this requires large amounts of energy.


No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Crude oil, cracking and hydrocarbons resources »