The newest 10 of 10 written questions. Open one to see it on the real paper.
The reaction between chlorine, Cl,, and sodium iodide, Nal, has a low activation energy. State what is meant by activation energy.
See it on the paper →State which letter represents the activation energy, E,, for the reaction.
See it on the paper →The enthalpy change, ΔH, for the reaction is negative. Fig. 7.1 shows two reaction pathway diagrams, A and B. A B products reactants energy energy products reactants progress of reaction progress of reaction Fig. 7.1 State which of these reaction pathway diagrams, A or B, represents the energy change for this reaction....
See it on the paper →Complete Fig. 7.2 to show an energy level diagram for the reaction. energy Label the activation energy and the energy change (enthalpy change) on your diagram. 2H 2 O + O 2 progress of reaction
See it on the paper →State the activation energy for the reaction. activation energy = kJ / mol
See it on the paper →The student repeats the experiment using a catalyst. State the effect of using a catalyst on the activation energy for the reaction.
See it on the paper →Fig. 2.2 shows the energy level diagrams for two different reactions, A and B. Reaction A and reaction B are done under the same conditions. reaction A energy reaction B energy 15 kJ 25 kJ 10 kJ 10 kJ progress of reaction progress of reaction Fig. 2.2 Reaction A happens faster than reaction B. Explain why. Use informat...
See it on the paper →Use Fig. 2.3 to calculate the activation energy for the reaction. activation energy = kJ
See it on the paper →Describe what is meant by the term activation energy.
See it on the paper →Label the activation energy on Fig. 5.3.
See it on the paper →Comprehensive responses • Most candidates identified the letter B. Limited responses • Some candidates identified the letter A instead of the letter B.
— Examiner report, February/March 2026, 0654/42 Q6(b)(i) (Cambridge)
Stronger candidates subtracted the values correctly. Many read the energy for the top of the hump and so 74 kJ / mol was a very common incorrect response.
— Examiner report, May/June 2025, 0654/43 Q8(b)(i) (Cambridge)
The role of a catalyst was quite well known. Some discussed it speeding up the reaction or thought the activation energy was increased.
— Examiner report, May/June 2025, 0654/43 Q8(c) (Cambridge)
Past papers, syllabus and examiner reports © UCLES (Cambridge University Press & Assessment). Questions are matched to topics from the official syllabus. AssessPro is independent and not endorsed by Cambridge.