Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Calorimetry experiments for determining the enthalpy changes of reactions
18 practice questions
Practice questions
11–18 of 18
Question 11
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 12
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 13
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 14
2 marks · Normal
Answer and see the solution →State the two steps needed to calculate the molar enthalpy change (ΔH) from calorimetry data.
Question 15
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.
Question 16
2 marks · Hard
Answer and see the solution →A student carries out a simple calorimetry experiment to measure the enthalpy change of combustion of a fuel. State two specific sources of error or limitations in this type of calorimetry experiment that could cause the measured value to be less exothermic (less negative) than the accepted value.
Question 17
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 18
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.