O-LevelChemistryRates of Reaction5070/11 · Oct/Nov 2025 · Q141 Mark

Some bond energy data are given in the table. Hydrazine, N2H4, reacts with oxygen, as shown. A value for the enthalpy change, ΔH, of this reaction is calculated by selecting and using data from the table. What is the value of ΔH?

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A-728 kJ/mol

B-568 kJ/mol

C-34 kJ/mol

D+352 kJ/mol

✓ Correct answer

B: -568 kJ/mol

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Topic: Rates of Reaction, O-Level Chemistry (syllabus 5070). Multiple choice, 1 mark.
Source: O-Level Chemistry, Oct/Nov 2025 Paper 1 Variant 1, question 14.

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