Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Calorimetry experiments for determining the enthalpy changes of reactions
18 practice questions
Practice questions
1–10 of 18
Question 1
1 mark · Easy
Answer and see the solution →State the main purpose of using a polystyrene cup in a calorimetry experiment to measure the enthalpy change of a reaction between two solutions.
Question 2
3 marks · Easy
Answer and see the solution →A student heats 80 g of water in a beaker using a chemical reaction. The temperature of the water rises from 20.2°C to 29.7°C. The specific heat capacity of water is 4.18 J/g°C.
(a)[1 mark]State the equation used to calculate the heat energy change (Q).
(b)[1 mark]Calculate the temperature change (ΔT) for this experiment. Show your working.
(c)[1 mark]Using your answer to (b), calculate the heat energy gained by the water (Q). Include the unit in your answer.
Question 3
2 marks · Easy
Answer and see the solution →In a calorimetry experiment, 2.60 g of potassium nitrate is dissolved in 65 g of water. The temperature of the water falls by 4.2°C. Calculate the molar enthalpy change (ΔH) for this process. The specific heat capacity of water is 4.18 J/g°C and the relative formula mass (M_r) for potassium nitrate is 101. Show your working. Give your answer in kJ/mol.
Question 4
2 marks · Easy
Answer and see the solution →A student’s value for the enthalpy change of combustion of methanol is much less exothermic than the accepted value found in data books. Explain two possible sources of error or limitations in the student’s calorimetry experiment.
Question 5
1 mark · Easy
Answer and see the solution →Name the piece of apparatus commonly used as a container for solution reactions in simple calorimetry experiments.
Question 6
3 marks · Easy
Answer and see the solution →(a)[1 mark]A student adds 40 g of water to a beaker. The initial temperature of the water is 22.0°C. A chemical reaction causes the temperature to rise to 30.5°C.
Calculate the temperature change, ΔT, for the water.
(b)[2 marks]The specific heat capacity of water is 4.18 J/g°C. Using your answer to part (a), calculate the heat energy gained by the water, Q, in joules. Give your answer to 2 significant figures.
Question 7
2 marks · Easy
Answer and see the solution →A student dissolves 3.21 g of potassium nitrate in 50 g of water. The temperature of the water falls by 5.0°C. The specific heat capacity of water is 4.18 J/g°C. Calculate the molar enthalpy change (ΔH) of solution for potassium nitrate. (Relative formula mass of KNO₃ = 101)
Give your answer in kJ/mol to 2 significant figures. Show your working.
Question 8
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 9
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 10
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.