SubjectCover

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

Calculation of enthalpy changes of reaction using bond energies

19 practice questions

Start practising (19 questions)

Practice questions

1–10 of 19

  1. Question 1

    1 mark · Easy

    What is the meaning of the term 'bond energy'?

    Answer and see the solution →

  2. Question 2

    3 marks · Easy

    (a)

    State whether bond breaking is exothermic or endothermic.

    [1 mark]
    (b)

    State whether bond making is exothermic or endothermic.

    [1 mark]
    (c)

    Explain your answer to part b.

    [1 mark]
    Answer and see the solution →

  3. Question 3

    2 marks · Easy

    Calculate the enthalpy change (ΔH) for the following reaction using the bond energies given below: Bond energies (kJ/mol):

    BondBond energy / kJ mol^{-1}
    H–H436
    Br–Br193
    H–Br366
    Answer and see the solution →

  4. Question 4

    2 marks · Easy

    Explain why a reaction is exothermic in terms of bond energies.

    Answer and see the solution →

  5. Question 5

    3 marks · Easy

    The table below gives bond energies (kJ/mol):

    BondBond energy / kJ mol^{-1}
    C–C151
    C–H413
    H–H436

    Use these values to answer the following about the reaction:

    (a)

    List all the bonds broken and all formed in this reaction.

    [1 mark]
    (b)

    Calculate the total energy required to break bonds in the reactant.

    [1 mark]
    (c)

    Calculate the enthalpy change (ΔH) for the reaction.

    [1 mark]
    Answer and see the solution →

  6. Question 6

    1 mark · Easy

    State the unit in which bond energy is measured.

    Answer and see the solution →

  7. Question 7

    3 marks · Easy

    Bond energies are given below:

    BondBond energy / kJ mol^{-1}
    N≡N946
    H–H436
    N–H388

    Use the bond energies to answer the following about the reaction:

    (a)

    Calculate the total energy needed to break all bonds in the reactants.

    [1 mark]
    (b)

    Calculate the total energy released by forming all bonds in the products.

    [1 mark]
    (c)

    Determine the enthalpy change (ΔH) for the reaction.

    [1 mark]
    Answer and see the solution →

  8. Question 8

    2 marks · Easy

    The reaction below occurs: Bond energies (kJ/mol): HI: 299, H–H: 436, I–I: 151 Calculate the enthalpy change (ΔH) for the reaction.

    Answer and see the solution →

  9. Question 9

    2 marks · Normal

    State the meaning of the term 'bond energy' and give the unit in which it is measured.

    Answer and see the solution →

  10. Question 10

    4 marks · Normal

    The reaction between ethane and chlorine is represented by the following equation:

    Use the bond energies given below for your calculations.

    Bond Energies
    BondBond energy / kJ mol^{-1}
    C–H413
    C–C348
    C–Cl338
    Cl–Cl243
    H–Cl432
    (a)

    List all bonds that are broken and all bonds that are formed in this reaction.

    [1 mark]
    (b)

    Calculate the total energy required to break the bonds in the reactants.

    [1 mark]
    (c)

    Calculate the total energy released when new bonds are formed in the products.

    [1 mark]
    (d)

    Calculate the enthalpy change () for the reaction. State whether the reaction is exothermic or endothermic.

    [1 mark]
    Answer and see the solution →