Question
CCEA Unit 2
Classify each of the following reactions as exothermic or endothermic. Give a reason in each case.
(a) Burning methane: CH₄ + 2O₂ → CO₂ + 2H₂O, ΔH = −890 kJ/mol [2 marks] (b) Thermal decomposition: CaCO₃(s) → CaO(s) + CO₂(g), ΔH = +178 kJ/mol [2 marks] (c) A student mixes two solutions and notices the temperature falls. [1 mark]
5 marks · take your time before peeking.
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Generated by TopMyGrade AI · cross-check official sources before relying on the mark-scheme phrasing.