Fuels

Below are links for Topic 5:

Crude Oil

Crude Oil Fractions

Combustion

Incomplete Combustion

Acid Rain

Climate Change

Biofuels

Choosing Fuels

Investigating Fuels PCA

Alkanes and Alkenes

Cracking

Polymerisation

Problems with Polymers

What you should know:

• 5.1 Be able to describe hydrocarbons as compounds that contain carbon and hydrogen only.
• 5.2 Be able to describe crude oil as a complex mixture of hydrocarbons.
• 5.3 Be able to describe the separation of crude oil into simpler, more useful mixtures by the process of fractional distillation.
  • (Note that details of fractional distillation are not required)
• 5.4 Know the name and uses of the following fractions:
  • a) gases, used in domestic heating and cooking
  • b) petrol, used as fuel for cars
  • c) kerosene, used as fuel for aircraft
  • d) diesel oil, used as fuel for some cars and trains
  • e) fuel oil, used as fuel for large ships and in some power stations
  • f) bitumen, used to surface roads and roofs
• 5.5 Be able to describe that hydrocarbons in different fractions differ from each other in:
  • a) the number of carbon and hydrogen atoms their molecules contain
  • b) boiling points
  • c) ease of ignition
  • d) viscosity
• 5.6 Be able to describe how the complete combustion of hydrocarbons:
  • a) involves the oxidation of the hydrocarbons
  • b) produces carbon dioxide and water
  • c) gives out energy
• 5.7 Be able to describe the chemical test for carbon dioxide (using limewater)
• 5.8 Be able to explain why the incomplete combustion of hydrocarbons can produce carbon and carbon monoxide.
• 5.9 Be able to describe how carbon monoxide behaves as a toxic gas.
• 5.10 Be able to demonstrate an understanding of the problems caused by incomplete combustion producing carbon monoxide and soot in appliances that use carbon compounds as fuels.
• 5.11 Be able to explain why impurities in some hydrocarbon fuels result in the production of sulfur dioxide.
• 5.12 Be able to demonstrate an understanding of some problems associated with acid rain caused when sulfur dioxide dissolves in rain water.
• 5.13 Be able to describe how various gases in the atmosphere, including carbon dioxide, methane and water vapour, trap heat from the Sun and that this keeps the Earth warm.
• 5.14 Be able to demonstrate an understanding that the Earth’s temperature varies and that human activity may influence this.
• 5.15 Be able to demonstrate an understanding that the proportion of carbon dioxide in the atmosphere varies due to human activity, and that chemists are investigating methods to control the amount of the gas in the atmosphere by:
  • a) iron seeding of oceans
  • b) converting carbon dioxide into hydrocarbons
• 5.16 Be able to evaluate how far the correlation between global temperature and the proportion of carbon dioxide in the atmosphere provides evidence for climate change.
• 5.17 Be able to describe biofuels as being possible alternatives to fossil fuels.
• 5.18 Know that one example of a biofuel is ethanol obtained by processing sugar cane or sugar beet and that it can be used to reduce the demand for petrol.
• 5.19 Be able to evaluate the advantages and disadvantages of replacing fossil fuels with biofuels, including:
  • a) the fact that biofuels are renewable
  • b) that growing the crops to make biofuels requires land and may affect the availability of land for growing food
  • c) the balance between the carbon dioxide removed from the atmosphere as these crops grow and the carbon dioxide produced when they are transported and burned
• 5.20 Be able to demonstrate an understanding of the factors that make a good fuel, including:
  • a) how easily it burns
  • b) the amount of ash or smoke it produces
  • c) the comparative amount of heat energy it produces (calculations involving conversion to joules are not required)
  • d) how easy it is to store and transport
• 5.21 Know that a simple fuel cell combines hydrogen and oxygen to form water and that this reaction releases energy.
• 5.22 Be able to evaluate the advantages and disadvantages of using hydrogen, rather than petrol, as a fuel in cars.
• 5.23 Be able to describe petrol, kerosene and diesel oil as non-renewable fossil fuels obtained from crude oil and methane as a non-renewable fossil fuel found in natural gas.
• 5.24 If done, revise the investigation of the temperature rise produced when the same volume of water is heated by different fuels.
• 5.25 Know that alkanes are saturated hydrocarbons, which are present in crude oil.
• 5.26 Know the formulae of the alkanes methane, ethane and propane, and be able to draw the structures of these molecules to show how the atoms are bonded together (no further knowledge of bonding is required in this unit).
• 5.27 Know that alkenes are unsaturated hydrocarbons.
• 5.28 Know the formulae of the alkenes ethene and propene, and be able to draw the structures of their molecules to show how the atoms are bonded together (no further knowledge of bonding is required in this unit).
• 5.29 Be able to describe how the bromine water test is used to distinguish between alkanes and alkenes.
• 5.30 Be able to describe how cracking involves the breaking down of larger saturated hydrocarbon molecules (alkanes) into smaller, more useful ones, some of which are unsaturated (alkenes).
• 5.31 HT only: be able to explain why cracking is necessary, including by using data on the composition of different crude oils and the demand for fractions in crude oil.
• 5.32 Be able to describe the cracking of liquid paraffin in a laboratory demonstration.
• 5.33 Know that:
  • a) many ethene molecules can combine together in a polymerisation reaction
  • b) the polymer formed is called poly(ethene) (conditions and mechanisms not required but for HT only equations required).
• 5.34 Be able to describe how other polymers can be made by combining together other monomer molecules, to include poly(propene), poly(chloroethene) (PVC) and PTFE.
• 5.35 Be able to relate uses of the polymers poly(ethene), poly(propene), poly(chloroethene) (PVC) and PTFE to the properties of the compounds
• 5.36 Recall that most polymers are not biodegradable, that they persist in landfill sites and that many produce toxic products when burnt
• 5.37 Be able to explain how some problems associated with the disposal of polymers can be overcome:
  • a) by recycling
  • b) by developing biodegradable polymers.