plumiEnergy changes in reactions: Edexcel GCSE Combined Science questions
Every Edexcel GCSE Combined Science exam question on Energy changes in reactions (specification points 7.9–7.16), 2018–2025, with its mark scheme and examiner’s report.
Paper
All papers
Exam
All years
Calculations
Q4(c)
The whole paper ↗Q6(e)
The whole paper ↗Q2(a)
The whole paper ↗Q2(b)(i)
The whole paper ↗Q2(b)(ii)
The whole paper ↗Q2(b)(iii)
The whole paper ↗Q2(b)(iv)
The whole paper ↗Q5(b)(ii)
The whole paper ↗Q5(c)
The whole paper ↗Q5(d)
The whole paper ↗Q2(a)
The whole paper ↗Q2(b)(i)
The whole paper ↗Q2(b)(ii)
The whole paper ↗Q2(b)(iii)
The whole paper ↗Q2(b)(iv)
The whole paper ↗Q5(b)(i)
The whole paper ↗Q5(b)(ii)
The whole paper ↗Q5(b)(iii)
The whole paper ↗Q2(a)
The whole paper ↗Q2(b)(i)
The whole paper ↗
All 54 questions on Energy changes in reactions, as a list
- June 2025, Chemistry Paper 2 Higher, Q4(c) (3 marks): Under extreme conditions, xenon reacts with fluorine to form xenon hexafluoride. The reaction is exothermic. The energy change for the reaction is –400 kJ mol–1
- June 2025, Chemistry Paper 2 Higher, Q6(e) (4 marks): Hydrogen iodide reacts with oxygen to form water and iodine. The equation for this reaction is 4HI + O2 → 2H2O + 2I2 Calculate the energy change for this reacti
- June 2025, Chemistry Paper 2 Foundation, Q2(a) (1 mark): Name the piece of apparatus labelled X in Figure 2. (1)
- June 2025, Chemistry Paper 2 Foundation, Q2(b)(i) (1 mark): State why the mixture is stirred in step 3. (1)
- June 2025, Chemistry Paper 2 Foundation, Q2(b)(ii) (2 marks): State two ways the apparatus could be changed to reduce the heat energy lost during the investigation. (2) 1 2
- June 2025, Chemistry Paper 2 Foundation, Q2(b)(iii) (2 marks): The student carries out the experiment three times. Figure 3 shows the results. initial temperature temperature of mixture temperature of water in °C after stir
- June 2025, Chemistry Paper 2 Foundation, Q2(b)(iv) (2 marks): Explain, using the information in Figure 3, the type of reaction that occurs when magnesium chloride dissolves in water. (2)
- June 2024, Chemistry Paper 2 Higher, Q5(b)(ii) (2 marks): The reaction of potassium with water is exothermic. On Figure 6, draw and label the reaction profile diagram for this reaction, labelling the activation energy.
- June 2024, Chemistry Paper 2 Higher, Q5(c) (3 marks): Some reactions are endothermic. Explain, in terms of bond breaking and bond forming, why some reactions are endothermic. (3)
- June 2024, Chemistry Paper 2 Higher, Q5(d) (4 marks): Ethene reacts with hydrogen chloride. Cl H H H Cl → H C C + H C C H H H H H Figure 7 shows the bond energies for the different bonds in the three molecules in t
- June 2024, Chemistry Paper 2 Foundation, Q2(a) (1 mark): In one reaction the temperature of the reaction mixture decreases. Which word describes this type of reaction? (1) A displacement B endothermic C exothermic D n
- June 2024, Chemistry Paper 2 Foundation, Q2(b)(i) (1 mark): State what is used to measure the temperature change in Figure 3. (1)
- June 2024, Chemistry Paper 2 Foundation, Q2(b)(ii) (1 mark): State one reason for using the piece of equipment A in Figure 3. (1)
- June 2024, Chemistry Paper 2 Foundation, Q2(b)(iii) (1 mark): A student suggests putting a lid on piece of equipment B. State why this would help to give a more accurate value for the temperature change. (1)
- June 2024, Chemistry Paper 2 Foundation, Q2(b)(iv) (4 marks): Four different salts, P, Q, R and S, are dissolved in water. Figure 4 shows the starting temperature of the water and the final temperature of the solution afte
- June 2023, Chemistry Paper 2 Higher, Q5(b)(i) (1 mark): Which arrow represents the activation energy for the reaction? (1) A arrow P B arrow Q C arrow R D arrow S
- June 2023, Chemistry Paper 2 Higher, Q5(b)(ii) (2 marks): Describe what the reaction profile shows about the energy involved in bond breaking and bond making in this reaction. (2)
- June 2023, Chemistry Paper 2 Higher, Q5(b)(iii) (4 marks): Figure 9 shows the energies of some bonds. bond bond energy in kJ mol–1 N N 944 H H 436 H N 388 Figure 9 The equation for the reaction between nitrogen and hydr
- June 2023, Chemistry Paper 2 Foundation, Q2(a) (1 mark): For steps 2 and 3, the student obtained the mass measurements shown in Figure 4 for the first salt. mass of empty boiling tube in g 22.52 mass of boiling tube +
- June 2023, Chemistry Paper 2 Foundation, Q2(b)(i) (2 marks): Calculate the temperature change for salt C. Include a sign to show if the temperature change is an increase or a decrease. (2) temperature change = °C
- June 2023, Chemistry Paper 2 Foundation, Q2(b)(ii) (2 marks): Explain which salt produces the biggest exothermic change. (2)
- June 2023, Chemistry Paper 2 Foundation, Q2(c) (2 marks): Explain why a polystyrene cup is a better container to use for this investigation than a glass beaker. (2)
- June 2022, Chemistry Paper 2 Higher, Q6(a)(i) (1 mark): Which row is correct about the energy changes for these processes? (1) energy change breaking a bond making a bond A energy is released energy is released B ene
- June 2022, Chemistry Paper 2 Higher, Q6(a)(ii) (4 marks): Hydrogen reacts with fluorine. H2 + F2 → 2HF Figure 7 shows the bond energies for the bonds in the three molecules in the equation. bond bond energy in kJ mol–1
- June 2022, Chemistry Paper 2 Higher, Q6(b) (6 marks): The reaction profile for an uncatalysed exothermic reaction is shown in Figure 8. energy reactants products progress of reaction Figure 8 Using some examples of
- June 2022, Chemistry Paper 2 Foundation, Q2(a) (1 mark): What does an exothermic reaction always give out? (1) A heat energy B light C a gas D sound
- June 2022, Chemistry Paper 2 Foundation, Q2(b)(i) (1 mark): Give the letter of the piece of apparatus, A, B, C or D, in Figure 3 that is used to measure the temperature. (1)
- June 2022, Chemistry Paper 2 Foundation, Q2(b)(ii) (1 mark): Give the name of the piece of apparatus B shown in Figure 3. (1)
- June 2022, Chemistry Paper 2 Foundation, Q2(b)(iii) (1 mark): The piece of apparatus labelled C is made from polystyrene. State why polystyrene is a better material than glass for this piece of apparatus. (1)
- June 2022, Chemistry Paper 2 Foundation, Q2(b)(iv) (3 marks): The results of the experiment are given in Figure 4. temperature of liquid at start in °C 18.6 temperature of products at end in °C 16.1 Figure 4 Calculate the
- November 2021, Chemistry Paper 2 Higher, Q1(b)(i) (2 marks): Explain how Figure 1 shows that dissolving ammonium chloride in water is an endothermic process. (2)
- November 2021, Chemistry Paper 2 Higher, Q1(b)(ii) (2 marks): Complete the reaction profile in Figure 1 and label the activation energy. (2)
- November 2021, Chemistry Paper 2 Higher, Q6(c) (4 marks): Figure 8 shows the reaction of propene, C3H6, with water. H H H H O H O C=C + H H C C C H H H H C H H H H H Figure 8 Figure 9 shows some bond energies. bond bon
- November 2021, Chemistry Paper 2 Foundation, Q5(b)(i) (2 marks): Explain how Figure 10 shows that dissolving ammonium chloride in water is an endothermic process. (2)
- November 2021, Chemistry Paper 2 Foundation, Q5(b)(ii) (2 marks): Complete the reaction profile in Figure 10 and label the activation energy. (2)
- November 2021, Chemistry Paper 2 Foundation, Q5(d)(i) (1 mark): Which symbol should be placed on a container of a toxic gas? (1) A B C D
- November 2021, Chemistry Paper 2 Foundation, Q5(d)(ii) (1 mark): Give one safety precaution that should be taken when working with toxic gases in the laboratory. (1)
- November 2020, Chemistry Paper 2 Higher, Q6(b) (4 marks): The energies of some bonds are shown in Figure 6. bond bond energy in kJ mol–1 C H 435 O O 496 C O 805 H O 463 Figure 6 Methane burns in oxygen to form carbon d
- November 2020, Chemistry Paper 2 Foundation, Q2(b)(i) (1 mark): Name a piece of apparatus that should be used to measure the 100 cm3 of water in step 1. (1)
- November 2020, Chemistry Paper 2 Foundation, Q2(b)(ii) (1 mark): The student cannot work out the temperature decrease using the method described. State what the student must do before step 2 to be able to work out the tempera
- November 2020, Chemistry Paper 2 Foundation, Q2(b)(iii) (1 mark): State why a polystyrene cup is used in this experiment. (1)
- November 2020, Chemistry Paper 2 Foundation, Q2(b)(iv) (2 marks): Figure 4 shows the reaction profile for this reaction. Use the words from the box to complete the labels on Figure 4. activation energy products reactants (2) h
- June 2019, Chemistry Paper 2 Higher, Q5(b) (3 marks): The reaction between calcium carbonate and dilute hydrochloric acid is exothermic. Explain, in terms of bond breaking and bond making, why some reactions are ex
- June 2019, Chemistry Paper 2 Foundation, Q3(a) (1 mark): Give the name of the apparatus that could be used to measure 1.00 g of calcium chloride. (1)
- June 2019, Chemistry Paper 2 Foundation, Q3(b) (2 marks): The student’s results were temperature of water at start = 21 °C temperature of mixture after stirring = 32 °C Explain, using these results, the type of heat en
- June 2019, Chemistry Paper 2 Foundation, Q3(c)(i) (1 mark): Which hazard symbol would be expected to be seen on a container of calcium chloride? (1) A B C D
- June 2019, Chemistry Paper 2 Foundation, Q3(c)(ii) (1 mark): Give a safety precaution that the student should take during the experiment. (1)
- June 2019, Chemistry Paper 2 Foundation, Q3(d) (1 mark): State one way in which the apparatus could be changed to reduce the amount of heat energy lost during the experiment. (1)
- June 2018, Chemistry Paper 2 Higher, Q4(d)(ii) (3 marks): In a cracking reaction, reactants are heated to form products. This reaction is endothermic. On the axes provided, draw the reaction profile of this reaction. L
- June 2018, Chemistry Paper 2 Foundation, Q1(a) (2 marks): The steps needed to carry out this experiment are P, Q, R, S and T. They are shown below. They are not in the correct order. P pour the 50 cm3 water into the po
- June 2018, Chemistry Paper 2 Foundation, Q1(b) (1 mark): The dissolving of this solid in water is an exothermic change. The experiment is repeated a number of times. Compared with the initial temperature of the water,
- June 2018, Chemistry Paper 2 Foundation, Q1(c) (1 mark): State how step R could be changed to measure the volume of water more accurately. (1)
- June 2018, Chemistry Paper 2 Foundation, Q1(d)(i) (2 marks): Explain why the pack goes cold. (2)
- June 2018, Chemistry Paper 2 Foundation, Q1(d)(ii) (1 mark): Give the reason why the pack can be used only once. (1)
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