11.3 Fuels

2026 Syllabus Objectives

  1. Core: Name the fossil fuels: coal, natural gas and petroleum
  2. Core: Name methane as the main constituent of natural gas
  3. Core: State that hydrocarbons are compounds that contain hydrogen and carbon only
  4. Core: State that petroleum is a mixture of hydrocarbons
  5. Core: Describe the separation of petroleum into useful fractions by fractional distillation
  6. Core: Describe how the properties of fractions obtained from petroleum change from the bottom to the top of the fractionating column, limited to: (a) decreasing chain length (b) higher volatility (c) lower boiling points (d) lower viscosity
  7. Core: Name the uses of the fractions as: (a) refinery gas fraction for gas used in heating and cooking (b) gasoline/petrol fraction for fuel used in cars (c) naphtha fraction as a chemical feedstock (d) kerosene/paraffin fraction for jet fuel (e) diesel oil/gas oil fraction for fuel used in diesel engines (f) fuel oil fraction for fuel used in ships and home heating systems (g) lubricating oil fraction for lubricants, waxes and polishes (h) bitumen fraction for making roads

Fossil Fuels 🔥

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What are Fossil Fuels?

Fossil fuels are fuels formed underground over geological periods of time from the remains of plants and animals. The three major fossil fuels are:

  • Coal - a black, solid fossil fuel formed from decayed vegetation
  • Natural gas - formed from dead sea creatures, more than 90% methane
  • Petroleum (crude oil) - formed from dead sea creatures under high pressure and temperature

Key Point: Fossil fuels were formed in the Earth's crust from material that was once living and contain hydrocarbons.

Formation of Fossil Fuels

The formation process varies depending on the type of fossil fuel:

  • Coal comes from plant material that underwent high pressure and temperature conditions
  • Petroleum and natural gas formed from the remains of marine microorganisms under similar conditions

Non-Renewable Resources ⚠️

Fossil fuels are classified as non-renewable (finite) resources - sources of energy formed in the Earth over many millions of years, which we are now using up at a rapid rate and cannot replace.

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