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

Organic Chemistry

785 practice questions

Start practising (785 questions)

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Practice questions

781–785 of 785

  1. Question 781

    8 marks · Normal

    Ethanol is used as a biofuel and is responsible for the sour taste in vinegar when it is oxidised to ethanoic acid.

    (a)

    Write a balanced symbol equation for the complete combustion of ethanol.

    [2 marks]
    (b)

    Calculate the mass of water produced when 4.60 g of ethanol ( C2H5OH , Mr = 46) burns completely in excess oxygen.

    [3 marks]
    (c)

    State the name and formula of the acid formed when ethanol is oxidised and explain briefly why it tastes sour.

    [2 marks]
    (d)

    On the label of a bottle of vinegar, ethanoic acid is listed as a main ingredient. Is ethanoic acid a strong or weak acid? Explain your answer.

    [1 mark]
    Answer and see the solution →

  2. Question 782

    8 marks · Normal

    This question is about oxidation reactions and the behaviour of carboxylic acids with metals.

    (a)

    Describe how ethanol can be oxidised in the laboratory using potassium dichromate(VI) and dilute sulfuric acid. State what observable change is seen in the reaction mixture.

    [3 marks]
    (b)

    After oxidation, a sample of the product is added to a test-tube containing magnesium ribbon. Describe two observations you would make and write a balanced symbol equation for the reaction.

    [3 marks]
    (c)

    Explain why ethanoic acid reacts more slowly with magnesium than hydrochloric acid does.

    [2 marks]
    Answer and see the solution →

  3. Question 783

    9 marks · Hard

    This question is about organic molecules and addition polymers.

    (a)

    Draw the structural formula and the displayed formula for the organic compound with the molecular formula C3H6.

    (i)

    Structural formula:

    [1 mark]
    (ii)

    Displayed formula:

    [1 mark]
    (b)

    Name the homologous series to which C3H6 belongs. State the general formula for this series.

    (i)

    Name of homologous series:

    [1 mark]
    (ii)

    General formula:

    [1 mark]
    (c)

    Poly(propene) is made by addition polymerisation of propene. Write a balanced chemical equation for the production of poly(propene) using displayed formulae for the monomer and the repeat unit of the polymer.

    (i)

    Displayed formula for the monomer:

    [1 mark]
    (ii)

    Displayed formula for the repeat unit of the polymer (show continuation bonds at the ends):

    [1 mark]
    (iii)

    Complete the balanced equation using your structures.

    [1 mark]
    (d)

    State one use of poly(propene).

    [1 mark]
    (e)

    Give one reason why addition polymers such as poly(propene) are difficult to dispose of.

    [1 mark]
    Answer and see the solution →

  4. Question 784

    9 marks · Hard

    Answer all parts about homologous series and the environmental impact of polymers.

    (a)

    Describe what is meant by a homologous series and give two features that members of a homologous series have in common.

    [2 marks]
    (b)

    The compounds below are all alkenes or alcohols. Use the general formulae to complete the table.

    General formulae for alkenes and alcohols
    NameGeneral formulaMolecular formula (for n = 4)
    Butene
    Butanol
    [3 marks]
    (c)

    Poly(chloroethene), also known as PVC, is a commonly used addition polymer. State one problem associated with the disposal of PVC and explain why it is not easily broken down in the environment.

    [2 marks]
    (d)

    Describe two environmental impacts that can arise from burning PVC in incinerators.

    [2 marks]
    Answer and see the solution →

  5. Question 785

    9 marks · Hard

    This question requires you to use your knowledge of organic functional groups and condensation polymers.

    (a)

    State what is meant by a functional group in organic chemistry and give the functional group present in all alcohols.

    [2 marks]
    (b)

    Ethane-1,2-diol (a diol) and hexane-1,6-dioic acid (a dicarboxylic acid) can react to form a polyester by condensation polymerisation.

    (i)

    Draw the displayed formula for ethane-1,2-diol.

    [1 mark]
    (ii)

    Draw the displayed formula for hexane-1,6-dioic acid.

    [1 mark]
    (iii)

    Write a balanced chemical equation (using structural formulae) for the formation of the polyester from ethane-1,2-diol and hexane-1,6-dioic acid. Include the structure of one repeat unit (use square brackets with 'n') and water.

    [2 marks]
    (c)

    Explain why polyesters are generally more biodegradable than addition polymers such as poly(ethene).

    [3 marks]
    Answer and see the solution →