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Using carbon fuels


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Fuels react with oxygen to release energy. Complete combustion happens in a plentiful supply of air and incomplete combustion occurs when the supply of air is limited.

Complete combustion releases more energy than incomplete combustion. Incomplete combustion also creates carbon monoxide, and more soot. Several factors must be considered when choosing the best fuel for a particular purpose.

Factors influencing the use of a fuel

The fossil fuels include coal, oil and natural gas. Various factors need to be considered when deciding how to use a fossil fuel. These include:

  • the energy value of the fuel in kJ/g of fuel
  • the availability of the fuel
  • how the fuel can be stored
  • the cost of the fuel
  • the toxicity of the fuel - whether it is poisonous
  • any pollution caused when the fuel is used, such as acid rain
  • how easy it is to use the fuel.

You are expected to be able to list factors such as the ones above.

Factories can cause air pollution

In general, solids such as coal are easier to store than liquids and gases but they are often more difficult to light. Liquids and gases ignite more easily. They also flow, which means they can be transported through pipelines.

Carbon dioxide is a greenhouse gas that contributes to global warming. The table shows some approximate energy values of the different fossil fuels, and the typical mass of carbon dioxide they produce when they burn.

Energy values of fuel

fuelenergy content (kJ/g)mg of carbon dioxide produced for each kJ
natural gas5253

Coal releases the least amount of energy per gram of fuel. It also produces the most carbon dioxide for a given amount of energy released when it burns.

You should be able to interpret data to choose the best fuel for a particular purpose.


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