Lesson 3.3.2.3

3.3.2.3 Combustion of alkanes Quiz: AQA Chemistry, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.3.2.3, Combustion of alkanes: 20 multiple choice questions for the AQA Chemistry (7405), Unit 3: Organic chemistry, written with Revision Ninja.

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The 20 questions

  1. Which type of combustion occurs when an alkane burns in excess oxygen?

    • Thermal cracking
    • Incomplete combustion
    • Catalytic cracking
    • Complete combustion

  2. Which set of products forms during incomplete combustion of an alkane?

    • CO and water
    • CO and hydrogen
    • CO2 and water
    • CO2 and hydrogen

  3. Which equation shows the complete combustion of methane?

    • CH4 + O2 -> CO + H2O
    • CH4 + 2O2 -> CO2 + H2
    • CH4 + O2 -> C + 2H2O
    • CH4 + 2O2 -> CO2 + 2H2O

  4. Which gas is a toxic product of incomplete combustion of alkanes in car engines?

    • Helium
    • Nitrogen
    • Carbon monoxide
    • Oxygen

  5. Which pollutant is formed in an internal combustion engine by reaction of nitrogen and oxygen at high temperature?

    • Methane
    • NOx
    • SO2 only
    • Ozone only

  6. Which device removes carbon monoxide and nitrogen oxides from exhaust emissions?

    • Catalytic converter
    • Fractionating column
    • Flue gas desulfuriser
    • Particulate filter

  7. Which environmental problem is caused directly by sulfur dioxide emissions?

    • Ozone depletion
    • Eutrophication
    • Global warming
    • Acid rain

  8. Why does calcium oxide react with sulfur dioxide in flue gas desulfurisation?

    • It is acidic
    • It is basic
    • It is oxidising
    • It is reducing

  9. Which compound is used to remove sulfur dioxide from flue gases?

    • Calcium carbonate
    • Sodium chloride
    • Copper oxide
    • Magnesium sulfate

  10. Which pollutant is produced mainly by incomplete combustion of hydrocarbons in engines?

    • Water vapour
    • Carbon dioxide
    • Nitrogen gas
    • Carbon monoxide

  11. What is the balanced equation for complete combustion of propane, C3H8?

    • C3H8 + 3O2 -> 3CO2 + 4H2O
    • C3H8 + 4O2 -> 3CO2 + 4H2O
    • C3H8 + 5O2 -> 3CO + 4H2O
    • C3H8 + 5O2 -> 3CO2 + 4H2O

  12. What volume of CO2 at room temperature and pressure (24 dm3 per mole) is produced by combustion of 0.10 mol of propane?

    • 0.40 mol CO2 = 9.6 dm3
    • 0.30 mol CO2 = 7.2 dm3
    • 0.10 mol CO2 = 2.4 dm3
    • 0.05 mol CO2 = 1.2 dm3

  13. Which pollutant is produced by the reaction of sulfur in fuel with oxygen?

    • Ozone
    • Nitrogen dioxide
    • Carbon monoxide
    • Sulfur dioxide

  14. What causes unburned hydrocarbons to be present in car exhaust gases?

    • Free-radical substitution
    • Thermal cracking
    • Complete combustion
    • Incomplete combustion

  15. How does a catalytic converter process carbon monoxide gas from engine emissions?

    • Decomposes to oxygen
    • Reduces to carbon
    • Hydrates to acid
    • Oxidises to CO2

  16. Which gaseous pollutant is reduced to nitrogen gas in a catalytic converter?

    • Carbon monoxide
    • Unburned hydrocarbons
    • Nitrogen oxides
    • Sulfur dioxide

  17. Why is complete combustion preferred over incomplete combustion when burning alkanes?

    • Releases less energy
    • Releases more energy
    • Produces carbon soot
    • Uses less oxygen

  18. Why does running an engine on a rich fuel-air mixture increase carbon monoxide production?

    • Excessive temperature
    • Insufficient fuel
    • Insufficient oxygen
    • Excess oxygen

  19. Which environmental phenomenon caused by sulfur dioxide damages stone buildings and lakes?

    • Thermal pollution
    • Ozone depletion
    • Acid rain
    • Smog formation

  20. Which equation correctly represents the complete combustion of butane?

    • C4H10 + 13O2 -> 4CO2 + 5H2O
    • 2C4H10 + 13O2 -> 8CO2 + 10H2O
    • 2C4H10 + 10O2 -> 8CO2 + 10H2O
    • C4H10 + 6O2 -> 4CO2 + 5H2O

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