CAIE A Level Chemistry 9701 · Chemical energetics
Methane burns in oxygen, , releasing heat, but the mixture must first be ignited. Nitrogen and oxygen react together, , only after the mixture has been heated strongly. Compare these two reactions in terms of the enthalpy change of reaction, , the balance between energy absorbed in breaking bonds and energy released in forming bonds, and the role of activation energy.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Compare means: Give similarities or differences between two things, and say which side each point belongs to. Write each point as a pair, for example: A is X, whereas B is Y. Two separate descriptions rarely earn the marks.
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