A-LevelChemistryChemical energeticsMay/June 2014Paper 1 Q111 Mark
The diagram shows the skeletal formula of cyclopropane. [Figure 11.1] The enthalpy change of formation of cyclopropane is +53.3 kJ mol⁻¹ and the enthalpy change of atomisation of graphite is +717 kJ mol⁻¹. The bond enthalpy of H−H is 436 kJ mol⁻¹ and of C−H is 410 kJ mol⁻¹. What value for the average bond enthalpy of the C−C bond in cyclopropane can be calculated from this data?
A187 kJ mol⁻¹
B315 kJ mol⁻¹
C351 kJ mol⁻¹
D946 kJ mol⁻¹
✓ Correct Answer
The correct answer is B: 315 kJ mol⁻¹
📋 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...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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