Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Measuring enthalpy changes of reactions
19 practice questions
Practice questions
1–10 of 19
Question 1
1 mark · Easy
Answer and see the solution →Name the piece of apparatus commonly used to measure temperature change in a calorimetry experiment.
Question 2
3 marks · Easy
Answer and see the solution →A student investigates the enthalpy change when sodium hydroxide solution reacts with hydrochloric acid in a polystyrene cup.
(a)[1 mark]State one reason why a polystyrene cup is used in this experiment.
(b)[1 mark]Write the name of one measurement (other than temperature) the student must take to calculate the enthalpy change.
(c)[1 mark]State the name of the reaction between sodium hydroxide and hydrochloric acid.
Question 3
2 marks · Easy
Answer and see the solution →In a calorimetry experiment, 50.0 g of water absorbs 420 J of energy. Calculate the temperature rise of the water. (Specific heat capacity of water = 4.2 J/g°C)
Question 4
2 marks · Easy
Answer and see the solution →Explain why it is important to stir the solution while measuring the temperature change in a calorimetry experiment.
Question 5
3 marks · Easy
Answer and see the solution →A student performs a calorimetry experiment to investigate the reaction between calcium chloride and water. Their thermometer readings at one-minute intervals are shown in the table below:
Time (minutes) Temperature (°C) 0 21.0 1 23.1 2 24.8 3 24.5 4 24.1 (a)[1 mark]State the highest temperature recorded during the experiment.
(b)[1 mark]Calculate the temperature increase from 0 to the highest temperature.
(c)[1 mark]Suggest why the temperature decreases after 2 minutes.
Question 6
1 mark · Easy
Answer and see the solution →State the sign of the enthalpy change (ΔH) for an exothermic reaction.
Question 7
3 marks · Easy
Answer and see the solution →A student wants to measure the enthalpy change for the reaction: Describe three steps the student should take to ensure the experiment is as accurate as possible.
(a)[1 mark]Name one way to reduce heat loss during the experiment.
(b)[1 mark]State one way to improve the accuracy of temperature measurement.
(c)[1 mark]Give one way to ensure that the reaction mixture is uniform during the experiment.
Question 8
2 marks · Easy
Answer and see the solution →In a calorimetry experiment, a student mixes two solutions and records a 5.0 °C temperature rise. If 100 g of solution was used (specific heat capacity = 4.2 J/g°C), calculate the total heat energy released.
Question 9
2 marks · Normal
Answer and see the solution →A student adds dilute hydrochloric acid to sodium hydroxide in a polystyrene cup. The temperature of the mixture rises.
State the name of this type of experimental method, and state the reason a polystyrene cup is used.
Question 10
4 marks · Normal
Answer and see the solution →A student investigates the enthalpy change when magnesium reacts with dilute sulfuric acid in a calorimeter.
(a)[1 mark]State the measurements the student should take during the experiment.
(b)[1 mark]Explain why it is important to stir the mixture before taking the final temperature reading.
(c)[1 mark]Suggest one reason the measured enthalpy change might be lower than the actual value.
(d)[1 mark]Describe how the student could improve the accuracy of this experiment.