plumiWhy are there temperature changes in chemical reactions?: OCR GCSE Chemistry B questions
Every OCR GCSE Chemistry B exam question on C1.2 Why are there temperature changes in chemical reactions?, 2018–2025, with its mark scheme and examiner’s report.
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Calculations
Q6(c)(ii)
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Q7(a)
The whole paper ↗Q7(b)
The whole paper ↗Q8(a)
The whole paper ↗Q8(b)
The whole paper ↗Q2(c)(i)
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Q2(c)(ii)
The whole paper ↗Q2(c)(iii)
The whole paper ↗Q8(a)(ii)
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Q8(b)
The whole paper ↗Q8(c)(ii)
The whole paper ↗Q4(a)
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Q4(b)
The whole paper ↗Q4(c)
The whole paper ↗Q5(a)(i)
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Q5(a)(ii)
The whole paper ↗Q5(b)(i)
The whole paper ↗Q5(b)(ii)
The whole paper ↗Q5(c)
The whole paper ↗Q4(a)(i)
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All 65 questions on Why are there temperature changes in chemical reactions?, as a list
- June 2025, Paper 2 Foundation, Q6(c)(ii) (2 marks): When hydrogen and methanol (CH3OH) are burned as fuels they form products. Draw lines to connect each fuel burned to the correct products. Fuel burned Products
- June 2025, Paper 2 Foundation, Q7(a) (2 marks): Fig. 7.1 shows a reaction profile diagram for a reaction. Complete Fig. 7.1 by filling in the labels. Fig. 7.1 Energy Reactants Products Progress of reaction [2
- June 2025, Paper 2 Foundation, Q7(b) (6 marks): (b)* Fig. 7.2 shows the trend in energy changes when some compounds dissolve in water. Fig. 7.2 Compound Trend Potassium chloride Energy change becomes more end
- June 2025, Paper 4 Higher, Q8(a) (6 marks): (a)* A student does some experiments to investigate the trends in energy changes when ionic compounds dissolve in water. The diagram shows the apparatus the stu
- June 2025, Paper 4 Higher, Q8(b) (3 marks): Fig. 8.1 shows a reaction profile diagram for a catalysed and an uncatalysed reaction. Fig. 8.1 Energy Reactants Products Progress of reaction Complete Fig. 8.1
- June 2024, Paper 1 Foundation, Q2(c)(i) (1 mark): Describe what happens to the temperature during the reaction. [1]
- June 2024, Paper 1 Foundation, Q2(c)(ii) (1 mark): The diagram shows the reaction profile for an exothermic reaction. Draw an arrow on the diagram to show the activation energy. Energy reactants products Progres
- June 2024, Paper 1 Foundation, Q2(c)(iii) (1 mark): What is meant by the term activation energy? [1]
- June 2024, Paper 3 Higher, Q8(a)(ii) (1 mark): Combustion of natural gas increases the temperature of the surroundings. Name of the type of reaction that increases the temperature of the surroundings. [1]
- June 2024, Paper 3 Higher, Q8(b) (3 marks): Hydrogen can also be used as an energy source in a fuel cell. The balanced symbol equation for the reaction in the hydrogen fuel cell is: 2H2 + O2 2H2O The tabl
- June 2024, Paper 3 Higher, Q8(c)(ii) (2 marks): Evaluate the impact on the environment of producing and using hydrogen and diesel as fuels. [2]
- June 2023, Paper 2 Foundation, Q4(a) (3 marks): Complete the symbol equations for the reactions in each fuel cell. Use information from the diagram. CH4 + 2 CO2 + 2 H2 + 2 [3]
- June 2023, Paper 2 Foundation, Q4(b) (3 marks): The table shows the sources of methane and hydrogen. Fuel Source Methane Extracted as a fossil fuel Hydrogen Electrolysis of water Explain the advantages to the
- June 2023, Paper 2 Foundation, Q4(c) (1 mark): A mixture of hydrogen and oxygen is very flammable but does not explode until it is ignited by a flame. Which statement explains why? Tick (3) one box. The flam
- June 2023, Paper 2 Foundation, Q5(a)(i) (2 marks): Name two pieces of measuring equipment Jamal needs to use in his experiment. 1 2 [2]
- June 2023, Paper 2 Foundation, Q5(a)(ii) (2 marks): Which two variables does Jamal need to control in his experiment? Tick (3) two boxes. The final temperature. The mass of the solid. The time taken to dissolve t
- June 2023, Paper 2 Foundation, Q5(b)(i) (2 marks): Jamal thinks that the temperature changes in his experiment are too small. Which two changes could Jamal make to increase the temperature changes in his experim
- June 2023, Paper 2 Foundation, Q5(b)(ii) (2 marks): Which two solids shown in Table 5.1 dissolve in an exothermic reaction? Tick (3) two boxes. Explain your answer. A B C D Explanation [2]
- June 2023, Paper 2 Foundation, Q5(c) (3 marks): Jamal measures the temperature change when solid E dissolves in water. He repeats his experiment three times. Table 5.2 shows his results. Table 5.2 Temperature
- June 2023, Paper 4 Higher, Q4(a)(i) (1 mark): Label the activation energy, Ea, on the diagram. [1]
- June 2023, Paper 4 Higher, Q4(a)(ii) (2 marks): Explain the meaning of activation energy. Use ideas about bonds in your answer. [2]
- June 2023, Paper 4 Higher, Q4(b) (3 marks): The equation shows the molecules involved in the reaction between hydrogen and oxygen. H–H H–O–H + O=O H–H H–O–H The table shows the bond energies of the bonds
- June 2023, Paper 4 Higher, Q4(c) (3 marks): Evaluate the advantages and disadvantages of using hydrogen-oxygen fuel cells in space shuttles. [3]
- June 2023, Paper 4 Higher, Q5 (6 marks): 5* The box gives information about what happens when calcium chloride and ammonium chloride dissolve in water. There is an exothermic change when calcium chlori
- June 2022, Paper 1 Foundation, Q3(a)(i) (1 mark): Which energy level diagram shows the energy change when ammonium nitrate dissolves in water? Tick (✓) one box. Energy ammonium nitrate + water Progress Energy a
- June 2022, Paper 1 Foundation, Q3(a)(ii) (1 mark): Which label should be used for the product of the dissolving process? Tick (✓) one box. Ammonium nitrate liquid Ammonium nitrate solution Ammonium nitrate solve
- June 2022, Paper 1 Foundation, Q3(a)(iii) (1 mark): Which word describes this dissolving process? Tick (✓) one box. Decomposition Endothermic Exothermic Precipitation [1]
- June 2022, Paper 1 Foundation, Q3(b) (3 marks): Eve has some solid ammonium nitrate. Describe the experiment Eve can do to find out how far the temperature of the water falls when solid ammonium nitrate disso
- June 2022, Paper 2 Foundation, Q3(c)(ii) (1 mark): In each experiment, Beth notices that the potential difference of the cell decreases after a time. Why does this happen? Tick (3) one box. The concentration of
- June 2022, Paper 2 Foundation, Q3(d)(i) (2 marks): Use information from Table 3.2 to explain two advantages of using hydrogen, rather than petrol, as a fuel for cars. 1 2 [2]
- June 2022, Paper 2 Foundation, Q3(d)(ii) (2 marks): Use information from Table 3.2 to explain two reasons why hydrogen is more difficult to use as a fuel for cars than petrol. 1 2 [2]
- June 2022, Paper 3 Higher, Q4(a) (1 mark): What word describes a reaction that releases energy to the surroundings? [1]
- June 2022, Paper 3 Higher, Q4(b) (2 marks): The equation for the reaction is: 2H2(g) + O2(g) 2H2O(l) Complete Fig. 4.1 to show the reaction profile for this reaction. Include on Fig. 4.1: • the formulae o
- June 2022, Paper 3 Higher, Q4(c) (1 mark): Which statement describes the activation energy? Tick (✓) one box. The energy absorbed by the reaction. The energy given out by the reaction. The energy needed
- June 2022, Paper 3 Higher, Q4(d) (3 marks): Fig. 4.2 shows what happens when 2 moles of hydrogen burn: O H H H H O O + O H H H H Fig. 4.2 Calculate the energy given out when 2 moles of hydrogen burn. Use
- June 2022, Paper 4 Higher, Q8(b)(i) (1 mark): Beth wants to make sure that she gets the highest possible potential difference from the fuel cell. She makes sure that she uses double the volume of hydrogen c
- June 2022, Paper 4 Higher, Q8(b)(ii) (2 marks): Use the half equations to write an overall equation for the reaction that happens in the fuel cell. [2]
- June 2022, Paper 4 Higher, Q8(b)(iii) (1 mark): A fuel cell filled with potassium hydroxide solution works better than a fuel cell filled with pure water. One reason it works better is because potassium hydro
- June 2022, Paper 4 Higher, Q8(b)(iv) (1 mark): Use the equations to suggest one other reason why using potassium hydroxide solution helps the fuel cell to work better. [1]
- June 2022, Paper 4 Higher, Q8(c) (1 mark): Beth uses a fixed amount of hydrogen and oxygen gas. After a time the potential difference of the cell decreases. Explain why this happens. [1]
- June 2022, Paper 4 Higher, Q8(d)(i) (2 marks): Explain why she is correct. [2]
- June 2022, Paper 4 Higher, Q8(d)(ii) (1 mark): Give one disadvantage of using a hydrogen fuel cell rather than diesel for a submarine. [1]
- November 2021, Paper 1 Foundation, Q6(e)(ii) (1 mark): What name is given to a reaction that gives out heat? [1]
- November 2021, Paper 1 Foundation, Q6(e)(iii) (1 mark): Draw one line to show the energy level of ‘blue copper sulfate’ on the reaction profile in Fig. 6.2. Label your line ‘blue copper sulfate’. Energy ‘white copper
- November 2021, Paper 3 Higher, Q3(b) (3 marks): Draw and label the reaction profile for this reaction. Label the activation energy ‘AE’. Energy 4Fe + 3O2 Progress of the reaction [3]
- November 2020, Paper 1 Foundation, Q5(c) (1 mark): Lithium-ion batteries contain chemical cells. Which statement is the correct definition for a chemical cell? Tick (3) one box. A chemical cell produces its full
- November 2020, Paper 2 Foundation, Q7(a) (2 marks): How does the diagram show that this reaction is exothermic? Tick (3) two boxes. Energy is taken in at the start of the reaction. The activation energy is very l
- November 2020, Paper 2 Foundation, Q7(b)(i) (3 marks): Kai does an experiment to prove that when solid sodium hydroxide dissolves in water, an exothermic reaction happens. Write an outline plan for Kai’s experiment.
- November 2020, Paper 2 Foundation, Q7(b)(ii) (1 mark): This is the hazard warning symbol for solid sodium hydroxide. Kai wears gloves and goggles when he does his experiment. Explain why these are necessary. [1]
- November 2020, Paper 4 Higher, Q7(b) (6 marks): Calcium nitrate, Ca(NO3)2, and ammonium nitrate, NH4NO3, are ionic compounds which are used to make fertilisers. (b)* The energy changes that happen when solid
- June 2019, Paper 1 Foundation, Q4(a) (1 mark): Name the product of this reaction. [1]
- June 2019, Paper 1 Foundation, Q4(b) (2 marks): Most cars still use petrol as a fuel. Give two advantages of using hydrogen as a fuel for cars. 1 2 [2]
- June 2019, Paper 1 Foundation, Q4(c)(i) (1 mark): Which arrow, A, B, or C, shows the activation energy for the reaction? [1]
- June 2019, Paper 1 Foundation, Q4(c)(ii) (1 mark): Which arrow, A, B, or C, shows that the reaction is exothermic? [1]
- June 2019, Paper 1 Foundation, Q4(d)(ii) (2 marks): 4 g of hydrogen burns giving out 240 kJ of energy. How much energy is given out when 20 g of hydrogen burns? Energy = kJ [2]
- June 2019, Paper 2 Foundation, Q4(d) (3 marks): Complete the sentences about this reaction by putting a ring around one word in each line. The temperature increase shows that the reaction is endothermic / exo
- June 2019, Paper 2 Foundation, Q6(a) (2 marks): In process 1, the reactor reaches 60 °C without being heated. Explain why the reactor keeps hot without being heated. [2]
- June 2019, Paper 3 Higher, Q6(a) (2 marks): Suggest one advantage and one disadvantage of using fuel cells instead of petrol. Advantage Disadvantage [2]
- June 2019, Paper 3 Higher, Q6(b) (3 marks): Complete a reaction profile for the above reaction of hydrogen with oxygen. On the profile, show: • the formulae of reactants and products • the activation ener
- June 2019, Paper 3 Higher, Q6(c) (2 marks): Burning 10 g of hydrogen gives out 1200 kJ of energy. How much energy is given out when 1.0 mole of H2 burns? mass of substance Use the formula: number of moles
- June 2019, Paper 4 Higher, Q6(a) (3 marks): Both process 1 and process 2 are exothermic. Explain why an exothermic reaction has a positive effect on how each process works. [3]
- June 2018, Paper 1 Foundation, Q2(a) (2 marks): Beth thinks that the reaction between sherbet and water is endothermic. She does an experiment to find out if she is right. Describe what she does. What result
- June 2018, Paper 1 Foundation, Q2(b) (3 marks): Complete the reaction profile for an endothermic reaction. Label your diagram with these words: products, activation energy reactants energy progress of the rea
- June 2018, Paper 3 Higher, Q10(b) (3 marks): This is an equation for the overall reaction that happens when water is electrolysed. 2H–O–H 2H–H + O=O Bond Energy change (kJ / mol) H–H 434 O=O 498 O–H 464 Us
- June 2018, Paper 3 Higher, Q10(c) (3 marks): Complete the reaction profile for the electrolysis of water. Use these words to label the reaction profile. hydrogen oxygen water activation energy energy progr
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