Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Physical Chemistry
442 practice questions
Topics covered
Practice questions
41–50 of 442
Question 41
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 42
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 43
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 44
1 mark · Easy
Answer and see the solution →State the sign of the enthalpy change (ΔH) for an exothermic reaction.
Question 45
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 46
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 47
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 48
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.
Question 49
3 marks · Normal
Answer and see the solution →In a calorimetry experiment, 1.2 g of magnesium reacts with 100 cm³ of dilute hydrochloric acid. The temperature of the solution rises by 9.0 °C. Assume the specific heat capacity of water is 4.18 J/g°C and the density of the solution is 1.00 g/cm³.
Calculate the heat evolved in the reaction. Give your answer in kJ (kilojoules).
Question 50
3 marks · Normal
Answer and see the solution →When measuring the enthalpy change of a reaction between zinc and copper(II) sulfate solution in a calorimeter, a student notices bubbles forming.
Explain why bubbles might affect the temperature readings in this experiment. Suggest two ways the experiment could be improved to obtain more accurate results.