Energetics: OCR GCSE Chemistry A questions

Every OCR GCSE Chemistry A exam question on C3.2 Energetics, 2018–2025, with its mark scheme and examiner’s report.

All 87 questions on Energetics, as a list

June 2025, Paper 1 Foundation, Q5 (1 mark): What is meant by activation energy? A The maximum amount of energy needed to end a reaction. B The maximum amount of energy needed to start a reaction. C The mi
June 2025, Paper 1 Foundation, Q21(a)(i) (4 marks): The student collects the apparatus needed to do their investigation, as shown in Fig. 21.1. Fig. 21.1 Copper sulfate solution Beaker Copper sulfate Measuring Ma
June 2025, Paper 1 Foundation, Q21(a)(ii) (1 mark): The student does the experiment three times and records their results in Table 21.1. Table 21.1 Start temperature End temperature Temperature change Experiment
June 2025, Paper 1 Foundation, Q21(b) (2 marks): The student thinks they can improve their experiment to get more accurate results. Suggest one improvement they can make to the apparatus shown in Fig. 21.1. Ex
June 2025, Paper 1 Foundation, Q21(c)(i) (3 marks): Label on Fig. 21.2 the: • Reactants • Products • Activation energy • Energy change. [3]
June 2025, Paper 1 Foundation, Q21(c)(ii) (1 mark): Is the reaction shown in Fig. 21.2 endothermic or exothermic? Tick (✓) one box. Endothermic Exothermic Explain your answer. [1]
June 2025, Paper 2 Foundation, Q12 (1 mark): What is a disadvantage of using a hydrogen/oxygen fuel cell instead of petrol to power a car? A Hydrogen is a renewable resource. B Hydrogen is difficult to sto
June 2025, Paper 3 Higher, Q12 (1 mark): Ethene reacts with bromine to form dibromoethane. What is the energy change for the reaction? Energy required to Energy released from break bonds (kJ / mol) for
June 2025, Paper 3 Higher, Q18(a) (4 marks): The students collect the apparatus needed to test their theory. Describe an experiment the students can do to measure the increase in temperature. You can inclu
June 2025, Paper 3 Higher, Q18(b) (1 mark): The students do the experiment five times. The table shows the students’ results. Temperature increase Experiment (°C) 1 37 2 39 3 53 4 22 5 48 The students’ re
June 2025, Paper 3 Higher, Q18(c)(i) (1 mark): Which part of the reaction profile shows the activation energy? Tick (✓) one box. A B C [1]
June 2025, Paper 3 Higher, Q18(c)(ii) (1 mark): Which part of the reaction profile shows the energy change? Tick (✓) one box. A B C [1]
June 2025, Paper 4 Higher, Q8 (1 mark): What is a disadvantage of a hydrogen/oxygen fuel cell? A Electricity is generated directly from the reaction. B Greenhouse gases are not produced. C Hydrogen ga
June 2024, Paper 1 Foundation, Q12 (1 mark): The table shows the start and end temperatures of four reactions. Which reaction is endothermic? Temperature at start (°C) Temperature at end (°C) A 19.0 19.0 B
June 2024, Paper 1 Foundation, Q13 (1 mark): Which reaction profile shows an exothermic reaction with the arrow marking the activation energy? A Energy Progress of reaction B Energy Progress of reaction C
June 2024, Paper 3 Higher, Q18(a)(i) (1 mark): Explain how you can tell the reaction profile is for an exothermic reaction. [1]
June 2024, Paper 3 Higher, Q18(a)(ii) (2 marks): Describe one difference and one similarity the scientist will see in the reaction profile for the endothermic reaction. Difference Similarity [2]
June 2024, Paper 3 Higher, Q18(b)(i) (3 marks): Calculate the energy transferred when all the bonds form in the products. Energy transferred = kJ / mol [3]
June 2024, Paper 3 Higher, Q18(b)(ii) (2 marks): The energy transferred when all the bonds break in the reactants is 6480 kJ / mol. Use your answer to part (b)(i) to calculate the energy change for this reacti
June 2024, Paper 3 Higher, Q18(c)(i) (3 marks): Some possible steps for a method are given in the list. Write five steps from the list in the correct order to describe the method the student should use. A Add
June 2024, Paper 3 Higher, Q18(c)(ii) (2 marks): The student plots their results on a graph. 26 25 24 23 Temperature (°C) 22 21 20 19 18 0 50 100 150 200 250 300 350 400 Time (seconds) The student concludes th
June 2024, Paper 4 Higher, Q10 (1 mark): Which equation shows the reaction at the anode in a hydrogen/oxygen fuel cell? 2H+(aq) + 2e– A H2(g) 4H+(aq) + O2(g) + 4e– B 2H2O(g) C 2H2(g) + O2(g) 2H2O(g) O2
June 2023, Paper 1 Foundation, Q9 (1 mark): Which reaction profile has an arrow showing the activation energy? A B Energy Energy Progress of reaction Progress of reaction C D Energy Energy Progress of rea
June 2023, Paper 1 Foundation, Q22(a)(i) (3 marks): Label the equipment in the diagram. Beaker [3]
June 2023, Paper 1 Foundation, Q22(a)(ii) (1 mark): Suggest one change the student can make so that the temperature change is measured more accurately. Use the diagram. [1]
June 2023, Paper 1 Foundation, Q22(b)(i) (2 marks): Plot the results from the table on the grid. Temperature (°C) Volume of acid (cm3) [2]
June 2023, Paper 1 Foundation, Q22(b)(ii) (2 marks): Describe what happens to the temperature measured as the acid is added. [2]
June 2023, Paper 1 Foundation, Q22(b)(iii) (1 mark): The reaction is exothermic. Explain how you can tell this from the student’s results. [1]
June 2023, Paper 1 Foundation, Q22(c) (1 mark): The activation energy for the student’s reaction is 132 kJ / mol. Complete the sentence to state the meaning of activation energy. Activation energy is the mini
June 2023, Paper 2 Foundation, Q18(b)(i) (2 marks): Plot a graph of the data from the table. [2]
June 2023, Paper 2 Foundation, Q18(b)(ii) (1 mark): Draw a curve of best fit on your graph. [1] 56 55 54 53 Energy given out 52 (kJ) 51 50 49 48 0 1 2 3 4 5 6 Number of carbon atoms
June 2023, Paper 2 Foundation, Q18(b)(iii) (1 mark): The energy given out when 1 g of butane burns is missing from the table. Use the graph to estimate the energy given out by butane. Energy given out by butane =
June 2023, Paper 2 Foundation, Q18(b)(iv) (1 mark): What name is given to the type of reaction that gives out energy? [1]
June 2023, Paper 3 Higher, Q17(a)(i) (3 marks): Label the equipment in the diagram. Beaker [3]
June 2023, Paper 3 Higher, Q17(a)(ii) (1 mark): Suggest one change the student can make so that the temperature change is measured more accurately. Use the diagram. [1]
June 2023, Paper 3 Higher, Q17(b)(i) (2 marks): Plot the results from the table on the grid. Temperature (°C) Volume of acid (cm3) [2]
June 2023, Paper 3 Higher, Q17(b)(ii) (2 marks): Describe what happens to the temperature measured as the acid is added. [2]
June 2023, Paper 3 Higher, Q17(b)(iii) (1 mark): The reaction is exothermic. Explain how you can tell this from the student’s results. [1]
June 2023, Paper 3 Higher, Q17(c) (1 mark): The activation energy for the student’s reaction is 132 kJ / mol. Complete the sentence to state the meaning of activation energy. Activation energy is the mini
June 2023, Paper 3 Higher, Q22(b) (4 marks): The decomposition of magnesium nitrate is an endothermic reaction. Complete the reaction profile for an endothermic reaction. Include the labels: • products • a
June 2023, Paper 4 Higher, Q9 (1 mark): Which statement about chemical cells is correct? A They produce a voltage indefinitely. B They produce a voltage once all of the reactants are used up. C They p
June 2023, Paper 4 Higher, Q15 (1 mark): What is the half equation for the reaction at the anode in a hydrogen/oxygen fuel cell? A 2H2 + O2 2H2O 4H+ + 4e– B 2H2 4H+ + 4e– C 2H2 4H+ + O2 + 4e– D 2H2O Yo
June 2023, Paper 4 Higher, Q20(b) (1 mark): Table 20.1 lists the energy given out when 1 g of different alkanes burn. Table 20.1 Energy given Alkane out (kJ) butane 49.2 ethane 52.6 methane 55.6 propane 5
June 2022, Paper 1 Foundation, Q20(a) (6 marks): Use the information in the table to state if each of the reactions, A and B, are exothermic or endothermic. Explain your answers. [6]
June 2022, Paper 1 Foundation, Q20(b)(i) (1 mark): The teacher measures the temperature of the reaction at the start and end of the reaction. What apparatus do they use to measure the temperature? [1]
June 2022, Paper 1 Foundation, Q20(b)(ii) (2 marks): The temperature of the reaction does not change. The teacher thinks too much heat is escaping from the apparatus. Suggest two ways they can improve the apparatu
June 2022, Paper 1 Foundation, Q20(c) (3 marks): The diagrams show the reaction profiles for four different reactions. Draw three lines to connect the reaction profile with its correct description. Reaction pr
June 2022, Paper 3 Higher, Q11 (1 mark): A student investigates an endothermic reaction. Their results are shown in the table. Temperature Bond energies less energy is needed to break bonds in reactant
June 2022, Paper 4 Higher, Q7 (1 mark): The table shows some of the advantages and disadvantages of using hydrogen/oxygen fuel cells to power vehicles. Advantage Disadvantage hydrogen fuel comes from
November 2021, Paper 2 Foundation, Q9 (1 mark): A chemical cell has a voltage of 1.50 V. What will the voltage be once the reactants are used up? A 0.00 V B 0.75 V C 1.50 V D 3.00 V Your answer [1]
November 2021, Paper 3 Higher, Q5 (1 mark): Which type of reaction occurs when the temperature of the surroundings increases? A Crystallisation B Endothermic C Exothermic D Reduction Your answer [1]
November 2021, Paper 3 Higher, Q22(c) (4 marks): The reaction of hydrogen sulfide with oxygen is shown using displayed formulae. O O H H O O O H H S S O O + + O O O H H O O H H S S The table shows the bond ene
November 2021, Paper 3 Higher, Q22(d)(i) (2 marks): Which type of reaction happens when sulfur dioxide and oxygen react? Tick (✓) one box. Endothermic Exothermic Reduction Thermal decomposition Give a reason for
November 2020, Paper 1 Foundation, Q19(a)(i) (1 mark): Add the temperature change for each reaction mixture. Include a + or – sign where relevant. Reaction Temperature at start Temperature at end Temperature change
November 2020, Paper 1 Foundation, Q19(a)(ii) (2 marks): Which reaction mixture has an endothermic reaction? Tick (3) one box. X Y Z Explain your answer. [2]
November 2020, Paper 1 Foundation, Q19(a)(iii) (3 marks): Complete the reaction profile for an endothermic reaction in Fig. 19.2. The products have already been added. Label the: • reactants • energy change • activatio
November 2020, Paper 1 Foundation, Q19(c) (2 marks): A student investigates the combustion of ethanol. Fig. 19.3 shows the apparatus the student uses. Thermometer Clamp Glass beaker Water Spirit burner Ethanol Fig
November 2020, Paper 2 Foundation, Q6 (1 mark): What happens to the potential difference of a chemical cell once the reactants are used up? A It decreases B It increases C It starts and finishes at 0 V D It s
November 2020, Paper 3 Higher, Q18(a)(ii) (1 mark): What term is used to describe a reaction that produces heat? [1]
November 2020, Paper 3 Higher, Q18(b) (1 mark): The student draws the reaction profile for this reaction, as shown in Fig. 18.1. Reactants Activation energy Energy Products Progress of reaction Fig. 18.1 Expl
November 2020, Paper 3 Higher, Q18(c)(i) (3 marks): The reaction of methane with oxygen produces heat. Explain why. Use ideas about bond breaking and bond making in your answer. [3]
November 2020, Paper 3 Higher, Q18(c)(ii) (1 mark): Calculate the total energy transferred to break the bonds in the reactants in Fig. 18.2. Total energy transferred = kJ / mol [1]
November 2020, Paper 3 Higher, Q18(c)(iii) (1 mark): Calculate the total energy transferred to make the bonds in the products in Fig. 18.2. Total energy transferred = kJ / mol [1]
November 2020, Paper 3 Higher, Q18(c)(iv) (1 mark): Use your answers to parts (ii) and (iii) to calculate the energy change for the reaction in Fig. 18.2. Energy change = kJ / mol [1]
June 2019, Paper 1 Foundation, Q11 (1 mark): What is meant by the activation energy in a chemical reaction? A The total energy used up when a reaction has stopped. B The energy absorbed during a reaction.
June 2019, Paper 1 Foundation, Q19(a)(i) (1 mark): The student notices that the temperature rises when a metal is added to the acid. What name is given to this type of reaction when the temperature rises? [1]
June 2019, Paper 1 Foundation, Q19(b)(i) (1 mark): One of the student’s results is anomalous. Put a ring around the anomalous result in the table. [1]
June 2019, Paper 1 Foundation, Q19(b)(ii) (1 mark): Suggest a reason why the result could be anomalous. [1]
June 2019, Paper 1 Foundation, Q19(b)(iii) (2 marks): Calculate the mean temperature change for magnesium. Give your answer to 1 decimal place. Mean temperature change = °C [2]
June 2019, Paper 1 Foundation, Q19(c)(i) (2 marks): The student wants to improve her experiment to get more accurate results. Suggest an improvement to her experiment, which will give more accurate results. Give
June 2019, Paper 1 Foundation, Q19(c)(ii) (2 marks): The student concludes that the more reactive the metal is, the higher the temperature rise. Describe further tests the student can do to confirm her conclusion.
June 2019, Paper 1 Foundation, Q19(d) (3 marks): A reaction profile shows the energy involved in a reaction. Draw the reaction profile for the reaction between magnesium and hydrochloric acid. Label the: • pro
June 2019, Paper 3 Higher, Q18(b) (1 mark): Ethanol can be used as a biofuel. The combustion of ethanol is an exothermic reaction. Explain why combustion is an exothermic reaction. Use ideas about bond br
June 2019, Paper 3 Higher, Q18(c)(i) (2 marks): Methanol is another biofuel that can be used in combustion reactions. CH3OH + 2O2 CO2 + 2H2O Look at the table. It shows some bond energies. Bond energy Bond (k
June 2019, Paper 3 Higher, Q18(c)(ii) (2 marks): Calculate the energy transferred when all the bonds form in the products. Energy transferred = kJ / mol [2]
June 2019, Paper 3 Higher, Q18(c)(iii) (1 mark): Use your answers to parts (i) and (ii) to calculate the energy change for this reaction. Energy change = kJ / mol [1]
June 2019, Paper 3 Higher, Q22(a)(i) (4 marks): The reaction in step 1 is an exothermic reaction. Draw a labelled reaction profile diagram for an exothermic reaction. Label the activation energy and the energ
June 2019, Paper 4 Higher, Q9 (1 mark): A hydrogen-oxygen fuel cell produces electricity. Hydrogen reacts with oxygen to produce water. What is the equation for the reaction that happens at the anode?
June 2018, Paper 1 Foundation, Q16(a) (3 marks): Complete the table. [3]
June 2018, Paper 1 Foundation, Q16(b) (1 mark): Which reaction has the largest energy change? Answer = [1]
June 2018, Paper 1 Foundation, Q16(c)(i) (1 mark): Calculate the energy change in this reaction. Answer = kJ [1]
June 2018, Paper 1 Foundation, Q16(c)(ii) (1 mark): Calculate the activation energy. Answer = kJ [1]
June 2018, Paper 3 Higher, Q9 (1 mark): What is the activation energy for a reaction? A The difference between the energy of the reactants and the products B The energy needed for a reaction to start
June 2018, Paper 3 Higher, Q21(a) (3 marks): Draw and label a reaction profile for this reaction. Energy Progress of the reaction [3]
June 2018, Paper 3 Higher, Q21(b) (3 marks): Two students investigate the burning of methane in oxygen. H O O H H O O H C H + C + O O O H H H O Methane Oxygen Carbon Water dioxide Look at the table of bond
June 2018, Paper 4 Higher, Q9 (1 mark): Look at the equations for the reactions that happen at each side of a hydrogen‑oxygen fuel cell. 2H2(g) → 4H+(aq) + 4e– Reaction 1: 4H+(aq) + O2(g) + 4e– → 2H2O
June 2018, Paper 4 Higher, Q16(d) (3 marks): Car manufacturers are developing cars that are powered by hydrogen/oxygen fuel cells. The table shows some information about a 200 km journey using an electric

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