OCR A Level Chemistry A
OCR A Level Chemistry A Enthalpy Changes Exam Questions
Free OCR A Level Chemistry A exam questions on Enthalpy Changes, with mark schemes. Covers enthalpy definitions, calorimetry, Hess's law and bond enthalpies.
Enthalpy Changes exam questions
1 question pack of real past exam questions with its mark scheme. Answer every question without notes, then mark your answers line by line against the mark scheme.
StemUp mark scheme flashcards
OCR A Level Chemistry A H432 Flashcards (Anki & Quizlet)
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Use them on Anki or Quizlet, then test yourself with the questions on this page.
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About OCR A Level Chemistry A Enthalpy Changes
This topic covers energy in reactions.
What you need to know
- Definitions Formation, combustion and neutralisation.
- Calorimetry q = mcΔT.
- Hess's law Enthalpy cycles.
- Bond enthalpies Average values and limitations.
Common mistakes in Enthalpy Changes
- Wrong sign for exothermic.
- Using total mass instead of water mass.
- Forgetting standard conditions.
Try three Enthalpy Changes exam-style questions
1. Calculate q when 50 g water rises 12 K. (1 mark)
Show the mark scheme answer
2508 J.
2. State Hess's law. (1 mark)
Show the mark scheme answer
Enthalpy change is independent of route.
3. Explain why bond enthalpy values differ from experiment. (1 mark)
Show the mark scheme answer
They are averages.
Enthalpy Changes FAQs
What does this topic cover?
Enthalpy changes, calorimetry and Hess's law.
Which practical links here?
Enthalpy change by calorimetry.
What are standard conditions?
100 kPa and a stated temperature, usually 298 K.
Revise this topic with flashcards: OCR A Level Chemistry A H432 Flashcards, with mark scheme answers for Anki and Quizlet.
