Chemical energetics: past paper questions

Where the questions come from

• Question 14May/June 2026, paper 11Multiple choice1 markHas a diagram

  The reaction pathway diagram for the reaction between hydrogen and iodine to form hydrogen iodide is shown. Four statements about this reaction are listed. 1 The reaction is exothermic.

  Try this question
• Question 12Oct/Nov 2025, paper 11Multiple choice1 mark

  What is always produced when a fuel is burned?

  Try this question
• Question 12Oct/Nov 2024, paper 11Multiple choice1 markHas a diagram

  Which reaction pathway diagram represents an endothermic reaction?

  Try this question
• Question 11Oct/Nov 2023, paper 11Multiple choice1 markHas a diagram

  The reaction pathway diagram for a reaction is shown. Which statements are correct?

  Try this question
• Question 13May/June 2026, paper 12Multiple choice1 mark

  Which statement describes an exothermic reaction?

  Try this question
• Question 13Oct/Nov 2025, paper 11Multiple choice1 markHas a diagram

  The reaction pathway diagram shows the energy of the reactants and products in a chemical reaction. Which row describes the enthalpy change and the type of reaction shown?

  Try this question
• Question 13Oct/Nov 2024, paper 11Multiple choice1 markHas a diagram

  The diagram shows a match. By striking the match, a chemical reaction takes place. Which row describes the chemical reaction?

  Try this question
• Question 13Oct/Nov 2023, paper 12Multiple choice1 markHas a diagram

  The initial and final temperatures of four different reactions are measured. Which reaction is the least exothermic?

  Try this question
• Question 14May/June 2026, paper 13Multiple choice1 mark

  Four changes are described. 1 When sodium is added to water, thermal energy is released. 2 When water boils, thermal energy is absorbed.

  Try this question
• Question 14Oct/Nov 2025, paper 12Multiple choice1 markHas a diagram

  Which experiment is the most exothermic?

  Try this question
• Question 14Oct/Nov 2024, paper 12Multiple choice1 markHas a diagram

  The temperature of the water in two beakers, X and Y, is measured as $21.5{}^{\circ }\text{C}$. $5\text{ g}$ of sodium chloride is dissolved in the water in beaker X. The temperature changes to $18.0{}^{\circ }\text{C}$.

  Try this question
• Question 13Oct/Nov 2023, paper 13Multiple choice1 markHas a diagram

  When water is added to anhydrous iron(III) chloride, ${\mathrm{F}\mathrm{e}\mathrm{C}\mathrm{l}}_3$, hydrated iron(III) chloride, ${\mathrm{F}\mathrm{e}\mathrm{C}\mathrm{l}}_3\cdot 6{\mathrm{H}}_2\mathrm{O}$, is formed and energy is given out.

  Try this question
• Question 1May/June 2026, paper 21Multiple choice1 markHas a diagram

  When water evaporates from a brass surface, the temperature of the brass surface decreases. Which row describes this evaporation process?

  Try this question
• Question 13Oct/Nov 2024, paper 13Multiple choice1 markHas a diagram

  Which row describes the reaction pathway diagram and energy change in an exothermic reaction?

  Try this question
• Question 15May/June 2026, paper 21Multiple choice1 mark

  Which equation represents an endothermic reaction?

  Try this question
• Question 14Oct/Nov 2025, paper 21Multiple choice1 mark

  Information about two reactions is given. ● The neutralisation reaction between citric acid and sodium hydrogencarbonate is endothermic. ● The displacement reaction between magnesium and carbon dioxide is exothermic.

  Try this question
• Question 14Oct/Nov 2024, paper 13Multiple choice1 markHas a diagram

  The table shows the initial and final temperatures for four different reactions. | reaction | initial temperature/${}^{\circ }\text{C}$ | final temperature/${}^{\circ }\text{C}$ | |---|---|---| | 1 | 19 | 28 | | 2 | 18 | 16 | | 3 | 20 | 20 | | 4 | 18 | 19 | Which reactions are endothermic?

  Try this question
• Question 11Oct/Nov 2023, paper 21Multiple choice1 markHas a diagram

  Hydrogen burns in oxygen. The equation for the reaction is shown. $$2{\text{H}}_2+{\text{O}}_2\to 2{\text{H}}_2\text{O}$$ The table shows the bond energies involved.

  Try this question
• Question 16May/June 2026, paper 21Multiple choice1 markHas a diagram

  The diagram shows the reaction pathway diagram for the reaction between $\text{X}$ and $\text{Y}$ to form product $\text{Z}$. The reaction happens more rapidly if a catalyst is used. How would the diagram change when a catalyst is used?

  Try this question
• Question 15Oct/Nov 2025, paper 21Multiple choice1 markHas a diagram

  The reaction pathway diagram for a reaction is shown. Which row identifies the activation energy, $E_{\mathrm{a}}$, and the enthalpy change, $\mathrm{\Delta }H$, for this reaction?

  Try this question
• Question 14Oct/Nov 2024, paper 21Multiple choice1 markHas a diagram

  Two reaction pathway diagrams are shown. Which arrow represents the activation energy for a reaction which releases thermal energy?

  Try this question
• Question 14May/June 2026, paper 22Multiple choice1 markHas a diagram

  Nitrogen trifluoride, ${\text{NF}}_3$, is used in the manufacture of certain types of solar panels. The equation for the formation of nitrogen trifluoride is shown.

  Try this question
• Question 14Oct/Nov 2025, paper 22Multiple choice1 markHas a diagram

  The equation for the combustion of hydrazine, ${\text{N}}_2{\text{H}}_4$, is shown.

  Try this question
• Question 14Oct/Nov 2024, paper 22Multiple choice1 markHas a diagram

  The equation for the formation of ammonia is shown. $${\mathrm{N}}_2+3{\mathrm{H}}_2\to 2{\mathrm{N}\mathrm{H}}_3$$ The reaction pathway diagram for the reaction is shown.

  Try this question
• Question 1May/June 2026, paper 23Multiple choice1 mark

  Gaseous ammonia reacts with an excess of gaseous hydrogen chloride in a sealed flask. $${\text{NH}}_3\text{(g)}+\text{HCl(g)}\to {\text{NH}}_4\text{Cl(s)}$$ The reaction is exothermic. Which statements about the reaction are correct?

  Try this question
• Question 15Oct/Nov 2025, paper 22Multiple choice1 markHas a diagram

  Dissolving ammonium chloride in water is an endothermic change. Which row shows the energy change and temperature change of the mixture during the dissolving of ammonium chloride?

  Try this question
• Question 14Oct/Nov 2024, paper 23Multiple choice1 markHas a diagram

  Which reaction pathway diagram is correctly labelled?

  Try this question
• Question 14Oct/Nov 2023, paper 22Multiple choice1 markHas a diagram

  Methane burns in oxygen to form carbon dioxide and water. $${\mathrm{C}\mathrm{H}}_4(\mathrm{g})+2{\mathrm{O}}_2(\mathrm{g})\to {\mathrm{C}\mathrm{O}}_2(\mathrm{g})+2{\mathrm{H}}_2\mathrm{O}(\mathrm{l})$$ The bond energies are shown.

  Try this question
• Question 17May/June 2026, paper 23Multiple choice1 markHas a diagram

  The equation for the reaction between hydrogen and chlorine is shown. $${\text{H}}_2\text{(g)}+{\text{Cl}}_2\text{(g)}\to 2\text{HCl(g)}$$ The energy required to break the H–H bond is $436\text{ kJ / mol}$.

  Try this question
• Question 16Oct/Nov 2025, paper 23Multiple choice1 mark

  Which statement about reactions is correct?

  Try this question