O-LevelChemistryRates of Reaction5070/12 · May/June 2015 · Q151 Mark

The energy diagram represents a chemical reaction carried out both with a catalyst and without a catalyst. What is the enthalpy change for the catalysed reaction?

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

A–125 kJ/mol

B–50 kJ/mol

C+75 kJ/mol

D+100 kJ/mol

✓ Correct answer

B: –50 kJ/mol

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Topic: Rates of Reaction, O-Level Chemistry (syllabus 5070). Multiple choice, 1 mark.
Source: O-Level Chemistry, May/June 2015 Paper 1 Variant 2, question 15.

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