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

Organic Chemistry

785 practice questions

Start practising (335 questions)

Topics covered

Practice questions

311–320 of 335 · Normal

  1. Question 311

    3 marks · Normal

    Explain why a polyester molecule contains ester groups and describe how these groups are formed during polymerisation.

    Answer and see the solution →

  2. Question 312

    4 marks · Normal

    The table shows the properties of two polyesters.

    Properties of Polyesters A and B
    PolyesterMonomers UsedMelting Point / CTensile Strength
    Aethane-1,2-diol + benzene-1,4-dicarboxylic acid258High
    Bpropane-1,3-diol + benzene-1,4-dicarboxylic acid140Medium
    (a)

    State one similarity and one difference in the monomers used to make Polyesters A and B.

    [2 marks]
    (b)

    Using the data in the table, suggest a reason for the difference in melting point between Polyester A and Polyester B.

    [2 marks]
    Answer and see the solution →

  3. Question 313

    1 mark · Normal

    Which of the following statements about polyesters is correct?

    1. A.Polyesters are formed by addition polymerisation of alkenes.
    2. B.Polyesters are made from diols and dicarboxylic acids by condensation polymerisation.
    3. C.Only one type of monomer is needed to form a polyester.
    4. D.No water is lost when making a polyester.
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  4. Question 314

    2 marks · Normal

    Give one everyday use of polyesters and state one property of polyesters that makes them suitable for this use.

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  5. Question 315

    4 marks · Normal

    (a)

    Write a balanced chemical equation using structural formulae for the reaction between ethane-1,2-diol (HOCH2CH2OH) and butane-1,4-dioic acid (HOOCCH2CH2CH2COOH) to form a polyester and water.

    [2 marks]
    (b)

    Explain why the product formed is called a polyester.

    [2 marks]
    Answer and see the solution →

  6. Question 316

    2 marks · Normal

    State the two types of functional groups present in lactic acid that allow it to form a biodegradable polyester.

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  7. Question 317

    4 marks · Normal

    Biodegradable polyesters such as PLA can be broken down by environmental processes more easily than many other polymers.

    (a)

    Explain what is meant by the term 'ester linkage' in a polyester.

    [1 mark]
    (b)

    Describe why polyesters with ester linkages are more biodegradable than addition polymers.

    [3 marks]
    Answer and see the solution →

  8. Question 318

    3 marks · Normal

    Lactic acid has the molecular formula . A single lactic acid molecule is used as the monomer for making polylactic acid (PLA).

    Calculate the molecular formula of the repeat unit of PLA, given that one molecule of water () is eliminated each time two lactic acid monomers link. Show your working.

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  9. Question 319

    4 marks · Normal

    The table shows the time taken for different types of polymers to degrade in soil:

    Degradation times of polymers in soil
    PolymerDegradation time (months)
    PLA (polylactic acid)12
    Poly(ethene)400
    Poly(ester)18
    Poly(propene)350

    Use the data to answer the questions.

    (a)

    Which polymer is the most biodegradable? Give the evidence from the table.

    [1 mark]
    (b)

    Explain, using your knowledge of chemical structure, why PLA degrades faster than poly(ethene) or poly(propene).

    [3 marks]
    Answer and see the solution →

  10. Question 320

    1 mark · Normal

    Which of the following shows the correct displayed formula for the repeat unit of polylactic acid (PLA)?

    1. A.—[O—CH(CH3)—CO]—
    2. B.—[CH2—CH(OH)—CO]—
    3. C.—[O—CH2—CO]—
    4. D.—[CH(OH)—CH3—COO]—
    Answer and check →