Engen Garage. Image credit chronicle.co.zw

Engen Garage. Image credit chronicle.co.zw

ZIMSEC O Level Combined Science Notes: Types of fuel

  • A fuel is any type of material that can be made to react (commonly with oxygen) and release energy in the process
  • Fuel provides energy to a body/machine to do work
  • Fuels contain energy stored in a chemical form
  • The stored chemical energy is converted into heat energy when the fuel is burnt
  • Most carbon compounds can be burnt in air (oxygen) to produce carbon dioxide and energy
  • Most carbon compounds can thus be used as fuels
  • There are different types of fuels
  • There are solid fuels
  • liquid fuels and
  • gaseous fuels

Solid fuels

Coal. Image credit alphabetics.info

Coal. Image credit alphabetics.info

  • Include wood, charcoal, coke and coal
  • Wood is popular in rural parts of Zimbabwe and Africa
  • This is because it is cheap despite its low energy content
  • It burns quickly making it inefficient
  • It produces smoke
  • It leads to deforestation
  • Charcoal is more efficient than wood
  • Charcoal is made by heating wood to very high temperatures in the absence of air
  • Wood is pile up
  • Covered with soil and grass before being ignited(set alight) through a small hole
  • Some of the wood burns, heating the rest in the process and converting it to charcoal
  • The resulting charcoal is nearly pure carbon
  • It is a porous, black substance
  • Coal also has a higher carbon content than wood and is thus more efficient
  • It also has a higher heating/energy value than wood

Liquid

  • Common liquid fuels include:
  • alcohol, ethanol, petrol, diesel and paraffin
  • ┬áPetrol, diesel and paraffin are all obtained by distilling Petroleum
  • Petroleum is also known as crude oil
  • All the fuels that are obtained from the distillation of crude oil are called hydrocarbon fuels
  • This is because their molecules contain only carbon and hydrogen atoms
  • Ethanol is produced at Triangle in Zimbabwe
  • Sugar is fermented
  • Ethanol is added to petrol/motor fuel to make Blend Petrol
  • It is also used in in Meth burners

Gaseous fuels

A gas flame. Image credit imperial.ac.uk

A gas flame. Image credit imperial.ac.uk

  • Examples of gas fuels include Natural Gas, Petroleum gas (often known as Liquid Petroleum Gas or LP gas) and Biogas
  • These gases usually contain propane and/or butane
  • Gases are usually cleaner,
  • and easier to control as they can be tapped to desired locations
  • They also do not contain contaminants which might leave solid residue

To access more topics go to the Combined Science Notes page.


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