A-LevelChemistryChemical energetics9701/12 · Oct/Nov 2024 · Q91 Mark

For which reaction is the enthalpy change an enthalpy change of formation?

AC(g) + 2H2(g) → CH4(g)

B½ N2(g) + ½ O2(g) → NO(g)

CNa2O(s) + SO3(g) → Na2SO4(s)

DPCl3(g) + Cl2(g) → PCl5(g)

✓ Correct answer

B: ½ N2(g) + ½ O2(g) → NO(g)

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Topic: Chemical energetics, A-Level Chemistry (syllabus 9701). Multiple choice, 1 mark.
Source: A-Level Chemistry, Oct/Nov 2024 Paper 1 Variant 2, question 9.

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