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

Coding for branched chains

19 practice questions

Start practising (19 questions)

Practice questions

11–19 of 19

  1. Question 11

    3 marks · Normal

    Explain how to identify a methyl side chain in the structural formula of an organic molecule. Your answer should refer to the features of methyl groups and how to recognize them.

    Answer and see the solution →

  2. Question 12

    4 marks · Normal

    Study the following table showing the names and structures of several branched alkanes.

    Branched Alkane Structures
    NameLongest chainSide chain(s)Position(s)
    2-methylbutanebutanemethyl2
    3-ethylpentanepentaneethyl3
    2,2-dimethylpropanepropanemethyl (x2)2,2
    4-methylhexanehexanemethyl4
    (a)

    Which molecule in the table has two side chains?

    [1 mark]
    (b)

    State the side chain and its position for 3-ethylpentane.

    [1 mark]
    (c)

    For which compound is the main chain the longest?

    [1 mark]
    (d)

    What is the coded name for a side chain containing two carbon atoms?

    [1 mark]
    Answer and see the solution →

  3. Question 13

    1 mark · Normal

    Which of the following is the correct IUPAC name for the molecule with this structural formula?

    Geometry diagram with points C1, C2, C3, C4, Me
    Skeletal formula: four carbon atoms in a row, with a methyl group attached to the second carbon.
    1. A.2-methylbutane
    2. B.3-methylbutane
    3. C.methylpropane
    4. D.2-ethylpropane
    Answer and check →

  4. Question 14

    2 marks · Normal

    State the coding for the following side chains used in organic nomenclature:

    (a)

    A one-carbon branch

    [1 mark]
    (b)

    A two-carbon branch

    [1 mark]
    Answer and see the solution →

  5. Question 15

    4 marks · Normal

    A hydrocarbon molecule contains six carbon atoms in its longest chain and a methyl group as a side chain.

    (a)

    What is the name of the six-carbon main chain?

    [1 mark]
    (b)

    If the methyl group is attached to carbon atom 2 (when numbered from the end closest to the side chain), give the IUPAC name of the compound.

    [2 marks]
    (c)

    Explain why it is important to number from the end of the chain closest to the side chain.

    [1 mark]
    Answer and see the solution →

  6. Question 16

    3 marks · Normal

    The systematic name of a hydrocarbon is 3-ethyl-2-methylpentane.

    State the number of carbon atoms in the longest chain, and give the total number of carbon atoms in the complete molecule.

    Show your reasoning.

    Answer and see the solution →

  7. Question 17

    2 marks · Hard

    A hydrocarbon molecule is named 4-methylhexane.

    Determine from which end of the main chain numbering should start to give the position of the methyl side chain, and explain your choice.

    Answer and see the solution →

  8. Question 18

    5 marks · Hard

    The following hydrocarbon is shown using its skeletal formula:

    Geometry diagram with points C1, C2, C3, C4, C5, M3A
    Skeletal formula of a branched alkane.
    (a)

    State the length (number of carbon atoms) in the longest chain of the molecule.

    [1 mark]
    (b)

    Name the side chain and state the carbon atom number on which it is attached.

    [2 marks]
    (c)

    Write the complete IUPAC name for this molecule.

    [2 marks]
    Answer and see the solution →

  9. Question 19

    2 marks · Hard

    Give the coding (name) for each of the following side chains found in organic molecules:

    Side chain structural formulaCode (name)
    \ce{CH_3}-
    \ce{CH_3CH_2}-
    Answer and see the solution →