Lesson 6B.1

6B.1 Alkanes, fuels and pollution Quiz: Pearson Edexcel Chemistry, Unit 6

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 6B.1, Alkanes, fuels and pollution: 20 multiple choice questions for the Pearson Edexcel Chemistry (9CH0), Unit 6: Organic Chemistry I, written with Revision Ninja.

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The 20 questions

  1. How many hydrogen atoms are in one molecule of octane, C8H18, compared with an alkene of the same carbon number?

    • The same number as the alkene, C8H16
    • Two more hydrogen atoms than the alkene, C8H16
    • Four more hydrogen atoms than the alkene, C8H14
    • Two fewer hydrogen atoms than the alkene, C8H14

  2. Which term describes alkanes and cycloalkanes?

    • Unsaturated hydrocarbons
    • Polymeric hydrocarbons
    • Aromatic hydrocarbons
    • Saturated hydrocarbons

  3. Which process separates crude oil into fractions by boiling point?

    • Fractional distillation
    • Reforming, which rearranges straight-chain alkanes into branched and cyclic hydrocarbons over a catalyst
    • Cracking, which breaks long hydrocarbon chains into smaller alkanes and alkenes using heat or a catalyst
    • Esterification, which joins an alcohol and a carboxylic acid to give an ester and water

  4. Which process breaks long-chain alkanes into shorter, more useful alkanes and alkenes?

    • Fractional distillation
    • Hydrogenation
    • Reforming
    • Cracking

  5. What is reforming in the context of crude oil processing?

    • Separating fractions by evaporating each one in a column and condensing it at its boiling point
    • Breaking alkenes into polymers under high pressure with a suitable catalyst
    • Converting straight-chain hydrocarbons into branched-chain alkanes and cyclic hydrocarbons
    • Adding hydrogen to alkenes so that the double bonds are saturated to form alkanes

  6. Which pollutants from fuel combustion cause acid rain?

    • Carbon dioxide and nitrogen gas
    • Carbon monoxide and carbon particulates
    • Unburned hydrocarbons and water vapour
    • Oxides of nitrogen and oxides of sulfur

  7. How does a catalytic converter reduce vehicle pollution?

    • It converts carbon monoxide to carbon dioxide and oxides of nitrogen to nitrogen
    • It removes carbon particulates by filtering them out of the exhaust
    • It converts carbon dioxide into oxygen for the engine
    • It adds sulfur to the fuel to neutralise nitrogen oxides

  8. Which statement best compares biodiesel with diesel from crude oil?

    • Biodiesel is made from renewable plant material, whereas diesel is from non-renewable crude oil
    • Biodiesel is a fossil fuel, whereas diesel is produced by fermentation
    • Biodiesel is made from crude oil, whereas diesel is made from renewable plant material
    • Biodiesel contains no carbon, whereas diesel contains only carbon

  9. Which pollutant is formed during incomplete combustion of alkane fuels?

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

  10. Write the equation for the complete combustion of methane. What volume of carbon dioxide is produced from 0.500 mol of methane at 24.0 dm3 mol-1?

    • 24.0 dm3
    • 6.00 dm3
    • 12.0 dm3
    • 1.00 dm3

  11. What mass of carbon dioxide is produced by the complete combustion of 16.0 g of methane? (Mr: CH4 = 16.0, CO2 = 44.0)

    • 22.0 g
    • 88.0 g
    • 16.0 g
    • 44.0 g

  12. Which equation represents the incomplete combustion of methane?

    • 2CH4 + 3O2 -> 2CO + 4H2O
    • CH4 + 2Cl2 -> CH2Cl2 + 2HCl
    • CH4 + 2O2 -> CO2 + 2H2O
    • CH4 -> C + 2H2

  13. What is the main environmental problem caused by oxides of sulfur released from fuel combustion?

    • Depletion of the ozone layer above the poles
    • Acid rain that damages buildings, soils and aquatic life
    • Accumulation of toxic heavy metals in fish
    • Increased concentration of oxygen in the atmosphere

  14. Why are carbon particulates and unburned hydrocarbons produced in engines?

    • The fuel contains too much oxygen for complete reaction
    • Nitrogen in the air reacts with carbon at high temperature
    • Combustion is incomplete, so some fuel is not fully oxidised
    • The catalyst is working too fast

  15. Which alkane is found in the largest proportion in natural gas?

    • Hexane
    • Methane
    • Pentane
    • Octane

  16. What is a suitable reason for the use of alcohols derived from plants as fuels?

    • They can only be made from crude oil using a refinery process at high temperature and pressure
    • They are renewable, unlike fossil fuels which will eventually run out
    • They have a higher energy density per gram than all fossil fuels and so need smaller storage tanks
    • They produce no carbon dioxide at all when burned, so they have no effect on the greenhouse gas balance

  17. Which compound is a cause of toxicity in the emissions from petrol engines?

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

  18. Which alkane is produced by reforming a straight-chain alkane to a more efficient fuel?

    • Hexane, a straight-chain alkane with six carbon atoms that burns with more knocking in engines
    • Heptane, a straight-chain alkane with seven carbon atoms used as a reference fuel in testing
    • 2,2,4-trimethylpentane
    • Decane, a straight-chain alkane with ten carbon atoms found in the heavier fractions of crude oil

  19. Which factor makes the combustion of alkanes exothermic?

    • The energy released when new bonds form in the products is greater than the energy needed to break bonds
    • The reaction is catalysed by high temperatures in the flame, which lowers the energy needed
    • Oxygen is always present in a large excess in every fuel combustion process in the home and factory
    • Alkanes contain carbon-carbon double bonds that release energy when they are broken in the flame

  20. Why is it important for catalytic converters to work at high temperature?

    • High temperature melts the fuel so that it burns completely without any formation of pollutants
    • High temperature stops carbon monoxide from forming by blocking the incomplete combustion pathway
    • High temperature makes nitrogen oxides more toxic and so the converter must be kept cool
    • The catalysts require high temperature to achieve a sufficient rate of reaction

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