Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Calculation of enthalpy changes of reaction using bond energies
19 practice questions
Practice questions
1–8 of 8 · Easy
Question 1
1 mark · Easy
Answer and see the solution →What is the meaning of the term 'bond energy'?
Question 2
3 marks · Easy
Answer and see the solution →(a)[1 mark]State whether bond breaking is exothermic or endothermic.
(b)[1 mark]State whether bond making is exothermic or endothermic.
(c)[1 mark]Explain your answer to part b.
Question 3
2 marks · Easy
Answer and see the solution →Calculate the enthalpy change (ΔH) for the following reaction using the bond energies given below: Bond energies (kJ/mol):
Bond Bond energy / kJ mol^{-1} H–H 436 Br–Br 193 H–Br 366 Question 4
2 marks · Easy
Answer and see the solution →Explain why a reaction is exothermic in terms of bond energies.
Question 5
3 marks · Easy
Answer and see the solution →The table below gives bond energies (kJ/mol):
Bond Bond energy / kJ mol^{-1} C–C 151 C–H 413 H–H 436 Use these values to answer the following about the reaction:
(a)[1 mark]List all the bonds broken and all formed in this reaction.
(b)[1 mark]Calculate the total energy required to break bonds in the reactant.
(c)[1 mark]Calculate the enthalpy change (ΔH) for the reaction.
Question 6
1 mark · Easy
Answer and see the solution →State the unit in which bond energy is measured.
Question 7
3 marks · Easy
Answer and see the solution →Bond energies are given below:
Bond Bond energy / kJ mol^{-1} N≡N 946 H–H 436 N–H 388 Use the bond energies to answer the following about the reaction:
(a)[1 mark]Calculate the total energy needed to break all bonds in the reactants.
(b)[1 mark]Calculate the total energy released by forming all bonds in the products.
(c)[1 mark]Determine the enthalpy change (ΔH) for the reaction.
Question 8
2 marks · Easy
Answer and see the solution →The reaction below occurs: Bond energies (kJ/mol): HI: 299, H–H: 436, I–I: 151 Calculate the enthalpy change (ΔH) for the reaction.