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

Covalent Bonding

68 practice questions

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Practice questions

21–28 of 28 · Easy

  1. Question 21

    3 marks · Easy

    Bonding and Atomic Arrangement
    Carbon AllotropeNumber of covalent bonds per carbon atomType of structure
    Diamond
    Graphite
    C60 fullerene

    Complete the table by filling in the number of covalent bonds per carbon atom and the type of structure for each allotrope.

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  2. Question 22

    1 mark · Easy

    State why graphite is soft.

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  3. Question 23

    3 marks · Easy

    (a)

    State the electrical conductivity for each of the following carbon structures: diamond, graphite, and C60 fullerene.

    [1 mark]
    (b)

    Explain why diamond does not conduct electricity.

    [1 mark]
    (c)

    Explain why graphite conducts electricity.

    [1 mark]
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  4. Question 24

    2 marks · Easy

    C60 fullerene contains 60 carbon atoms. If each carbon atom forms 3 bonds, calculate the total number of covalent bonds in one C60 molecule.

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  5. Question 25

    5 marks · Easy

    (a)

    Define a covalent bond.

    [1 mark]
    (b)

    Explain, in terms of electrostatic attraction, how a covalent bond holds two atoms together.

    [2 marks]
    (c)

    State one reason why many substances with simple molecular structures have low melting points.

    [1 mark]
    (d)

    Methane, CH, is a gas at room temperature. Explain why, using your knowledge of bonding and structure.

    [1 mark]
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  6. Question 26

    5 marks · Easy

    (a)

    Draw a dot-and-cross diagram to show the bonding in a molecule of hydrogen chloride (HCl).

    [2 marks]
    (b)

    State how many covalent bonds are present in a molecule of hydrogen chloride.

    [1 mark]
    (c)

    Chlorine is a gas at room temperature, but water (HO) is a liquid. Using ideas about relative molecular mass, explain this difference.

    [2 marks]
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  7. Question 27

    5 marks · Easy

    (a)

    Hydrogen (H) and carbon dioxide (CO) are both covalent molecules. Calculate the relative molecular mass (M) of each molecule. (Relative atomic masses: H = 1, C = 12, O = 16)

    [2 marks]
    (b)

    Which of these molecules would you expect to have a higher boiling point? Explain your answer in terms of molecular mass and intermolecular forces.

    [2 marks]
    (c)

    State the type of bonding present in both hydrogen and carbon dioxide molecules.

    [1 mark]
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  8. Question 28

    5 marks · Easy

    (a)

    Draw a dot-and-cross diagram to show the covalent bonding in a molecule of ammonia (NH).

    [2 marks]
    (b)

    Explain why ammonia is a gas at room temperature, using your understanding of intermolecular forces.

    [2 marks]
    (c)

    State how many lone pairs of electrons are present on the nitrogen atom in the ammonia molecule.

    [1 mark]
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