Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Energetics
117 practice questions
Topics covered
- Exothermic reactions19 practice questions
- Endothermic reactions19 practice questions
- Measuring enthalpy changes of reactions19 practice questions
- Calorimetry experiments for determining the enthalpy changes of reactions18 practice questions
- Why do reactions either give out or absorb heat?19 practice questions
- Calculation of enthalpy changes of reaction using bond energies19 practice questions
Practice questions
11–18 of 18 · Hard
Question 11
5 marks · Hard
Answer and see the solution →Describe how you would carry out a calorimetry experiment to determine the enthalpy change of a displacement reaction between magnesium and copper(II) sulfate solution in a school laboratory. Your answer should refer to apparatus, measurements, and how you would ensure reliable results.
(a)[1 mark]State the main pieces of apparatus you would use for this experiment.
(b)[2 marks]Describe the basic procedure for mixing the reactants and measuring the temperature change.
(c)[2 marks]Suggest two ways to improve the reliability or accuracy of the results in this experiment.
Question 12
2 marks · Hard
Answer and see the solution →A student adds 25.0 g of water at 22.0 °C to a beaker. After a reaction occurs, the final temperature of the water is 29.5 °C. The specific heat capacity of water is 4.18 J/g°C. Calculate the amount of heat absorbed by the water during the reaction. Give your answer in joules.
Question 13
2 marks · Hard
Answer and see the solution →A reaction is found to be exothermic overall. Explain, in terms of bond energies, why this is the case.
Question 14
5 marks · Hard
Answer and see the solution →When carbon monoxide reacts with oxygen, the following reaction occurs:
You are given the following average bond energies:
Bond Average bond energy (kJ/mol) C≡O 1072 O=O 498 C=O (in CO2) 805 (a)[2 marks]List one type of bond broken and one type of bond formed in this reaction.
(b)[1 mark]Explain why this reaction is exothermic, using bond energies.
(c)[2 marks]Calculate the enthalpy change, ΔH, for the reaction, using the bond energies in the table. Show your working and give the answer in kJ/mol (for the equation as written).
Question 15
2 marks · Hard
Answer and see the solution →Describe, in terms of bonds and energy, what happens during an endothermic reaction.
Question 16
2 marks · Hard
Answer and see the solution →The following reaction occurs:
Bond energies (in kJ/mol):
Bond Bond energy / kJ mol^{-1} H–H 436 F–F 158 H–F 565 Calculate the enthalpy change (ΔH) for the reaction using the bond energies given.
Question 17
5 marks · Hard
Answer and see the solution →Chloroethane can be made by reacting ethene with hydrogen chloride:
Bond energies (kJ/mol) Bond Bond energy / kJ mol^{-1} C=C 612 C–C 348 C–H 413 H–Cl 432 C–Cl 338 (a)[2 marks]Write down all the bonds broken and all the bonds formed in this reaction.
(b)[3 marks]Calculate the enthalpy change (ΔH), in kJ/mol, for the reaction using the bond energies provided. Show your working and give your answer to the nearest kJ/mol.
Question 18
2 marks · Hard
Answer and see the solution →A student calculates the enthalpy change for the following reaction using average bond energies:
Bond energies (kJ/mol):
Bond Bond energy / kJ mol^{-1} Cl–Cl 243 H–S 363 H–Cl 432 State the total energy required to break all the bonds in the reactants, and the total energy released when new bonds form in the products. Show your calculations.