A-LevelChemistryChemical energeticsMay/June 2025Paper 1 Q131 Mark
Under certain conditions, CCl4 and H2O react as shown. The activation energy for the reaction is +62 kJ mol⁻¹. CCl4 + 2H2O → CO2 + 4HCl ΔH = −61.5 kJ mol⁻¹ Which enthalpy profile diagram best fits this reaction?
ADiagram showing an exothermic reaction profile with the activation energy barrier above the reactants.
BDiagram showing an endothermic reaction profile with the activation energy barrier above the reactants.
CDiagram showing an exothermic reaction profile with a larger activation energy barrier above the reactants than option A.
DDiagram showing an endothermic reaction profile with the activation energy barrier above the reactants.
✓ Correct Answer
The correct answer is D. This question tests the candidate's understanding of chemical energetics within the Chemistrysyllabus. The examiner's mark scheme requires...
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🔒
Unlock the Examiner's Answer
Sign up for free to reveal the correct answer, the official mark scheme breakdown, and the examiner trap analysis for this question.
Sign Up Free to Unlock →Join thousands of Cambridge students already using Oracle Prep