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Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter

Alkanes

18 practice questions

Start practising (8 questions)

Practice questions

1–8 of 8 · Normal

  1. Question 1

    2 marks · Normal

    State the general formula of alkanes and explain what this formula represents.

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  2. Question 2

    4 marks · Normal

    The alkane with six carbon atoms is called hexane.

    (a)

    Write the molecular formula for hexane.

    [1 mark]
    (b)

    Draw the displayed (structural) formula of hexane.

    [2 marks]
    (c)

    Give the name of the alkane with three carbon atoms in a straight chain.

    [1 mark]
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  3. Question 3

    3 marks · Normal

    Octane (C8H18) can undergo substitution with chlorine in the presence of UV light.

    Write the balanced chemical equation for the mono-substitution reaction of octane with chlorine. Give the formulae for all reactants and products. Calculate the total number of hydrogen atoms remaining in all the organic product molecules if 5 moles of octane completely undergo mono-substitution.

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  4. Question 4

    3 marks · Normal

    Explain why alkanes have the general formula CnH2n+2, making reference to the bonding and structure of these molecules.

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  5. Question 5

    4 marks · Normal

    The table below shows the number of carbon and hydrogen atoms in three different unbranched alkanes.

    AlkaneNumber of carbon atomsNumber of hydrogen atoms
    Methane14
    Butane410
    Nonane920
    (a)

    Using the data, deduce the general formula connecting the number of hydrogen atoms (H) to the number of carbon atoms (C) in alkanes.

    [2 marks]
    (b)

    Predict the number of hydrogen atoms in a straight-chain alkane with 7 carbon atoms.

    [1 mark]
    (c)

    Name the alkane with 9 carbon atoms.

    [1 mark]
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  6. Question 6

    1 mark · Normal

    What is required for a substitution reaction between ethane and chlorine to take place?

    1. A.High pressure
    2. B.A catalyst
    3. C.Ultraviolet light
    4. D.Heating to 1000°C
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  7. Question 7

    2 marks · Normal

    What are the two elements found in all alkanes? State why alkanes are described as saturated.

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  8. Question 8

    4 marks · Normal

    Draw and name the displayed formulae for the following straight-chain alkanes.

    (a)

    An alkane with four carbon atoms.

    [2 marks]
    (b)

    An alkane with five carbon atoms.

    [2 marks]
    Answer and see the solution →