Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Calorimetry experiments for determining the enthalpy changes of reactions
18 practice questions
Practice questions
1–8 of 8 · Normal
Question 1
2 marks · Normal
Answer and see the solution →Describe how you would measure the enthalpy change of solution for a solid salt dissolving in water using a simple calorimetry experiment. Include two key steps in your answer.
Question 2
4 marks · Normal
Answer and see the solution →A student carries out a calorimetry experiment to find the amount of heat released in a neutralisation reaction between hydrochloric acid and sodium hydroxide. She mixes 50 g of solution at 21.0°C with sodium hydroxide. After the reaction, the temperature rises to 27.5°C. The specific heat capacity of water is 4.18 J/g°C.
(a)[1 mark]Calculate the temperature change (ΔT) of the solution.
(b)[1 mark]Write the equation used to calculate the heat energy change (Q) in this experiment.
(c)[2 marks]Calculate the total heat energy, in joules, released in this reaction. Show your working.
Question 3
3 marks · Normal
Answer and see the solution →In a calorimetry experiment, 1.25 g of magnesium reacts completely with excess hydrochloric acid. The temperature of the 100 g acid solution rises by 9.8°C. The specific heat capacity of the solution is 4.18 J/g°C. Calculate the molar enthalpy change (ΔH) of this reaction in kJ/mol. The relative atomic mass of magnesium, Mg, is 24.
Question 4
3 marks · Normal
Answer and see the solution →A student finds that their calculated enthalpy change of combustion for ethanol is much less exothermic than the value from data books. Explain three possible sources of error in their calorimetry experiment that could have led to this result.
Question 5
4 marks · Normal
Answer and see the solution →The table shows some data from a calorimetry experiment measuring the enthalpy change of a displacement reaction between iron and copper(II) sulfate:
Data from calorimetry experiment Volume of copper(II) sulfate solution / cm³ Mass of iron used / g Initial temperature / °C Maximum temperature / °C Specific heat capacity / J/g°C 60 2.4 18.4 24.7 4.18 (a)[1 mark]Calculate the temperature change (ΔT) for this reaction.
(b)[2 marks]Assume the density of the solution is 1 g/cm³. Calculate the heat energy change, Q, in joules.
(c)[1 mark]Suggest one assumption made in this calculation.
Question 6
1 mark · Normal
Answer and check →Which value must be measured directly in a calorimetry experiment in order to calculate the heat energy released using the equation Q = mcΔT?
- A.The temperature change of the water
- B.The pressure inside the calorimeter
- C.The colour of the solution
- D.The rate of reaction
Question 7
2 marks · Normal
Answer and see the solution →State the two steps needed to calculate the molar enthalpy change (ΔH) from calorimetry data.
Question 8
4 marks · Normal
Answer and see the solution →Neutralisation experiments using polystyrene cups are often used to calculate enthalpy changes of reaction.
(a)[1 mark]Give one reason why a polystyrene cup is used instead of a metal can.
(b)[1 mark]Suggest one way the experiment might underestimate the enthalpy change.
(c)[1 mark]State one possible way to minimise errors from heat lost during the experiment.
(d)[1 mark]Explain how using a lid can help improve the accuracy of a calorimetry result.