Exercise 1 — IGCSE 0653 May/Jun 2023 Paper 31 Q2
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thermometer
Cambridge IGCSE·Combined Sciences 0653·Chemistry
Chemical Energetics
Key knowledge — Chemical Energetics
Formulas & equations
q = mcΔT (energy = mass × specific heat capacity × temperature change)ΔH = energy of bonds broken − energy of bonds formed (endothermic if positive)
Key facts & rules
- Exothermic reaction: releases energy to surroundings → temperature rises. Products have less energy than reactants.
- Endothermic reaction: absorbs energy from surroundings → temperature falls. Products have more energy than reactants.
- Activation energy: minimum energy needed for a reaction to occur.
- Catalyst: lowers activation energy → increases reaction rate without being consumed.
- Bond breaking: endothermic (energy input needed). Bond forming: exothermic (energy released).
- If bonds broken > bonds formed (energy): overall endothermic.
- Energy level diagram: reactants → transition state (Ea peak) → products.
IGCSE Chemistry — Chemical Energetics
60 Cambridge IGCSE 0653 Combined Sciences past paper questions on chemical energetics, across Theory, Multiple Choice and Alternative to Practical.
About Chemical Energetics on IGCSE 0653
Exothermic reactions release energy to the surroundings; endothermic reactions absorb energy. Energy level diagrams show reactant and product energy levels and activation energy.
What's covered:
- Exothermic reactions: combustion, neutralisation
- Endothermic reactions: thermal decomposition
- Activation energy and energy level diagrams
- Bond breaking (endothermic) and bond forming (exothermic)
- Calculating energy changes from bond energies
Theory
Chemical Energetics — Core1 · Paper 3
Chemical Energetics — Extended4 · Paper 4
Exercise 1 — IGCSE 0653 May/Jun 2024 Paper 43 Q2
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activation energy correctly labelled on both diagrams
Exercise 2 — IGCSE 0653 May/Jun 2024 Paper 41 Q5
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activation energy shown as a maximum between reactants and products
Exercise 3 — IGCSE 0653 May/Jun 2024 Paper 42 Q5
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(overall) energy change is endothermic or more energy taken in than given out
Exercise 4 — IGCSE 0653 Oct/Nov 2023 Paper 41 Q5
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> 0 to < 20 (°C)
Multiple choice
Chemical Energetics — Core MCQ23 · Paper 1
Question 1 — IGCSE 0653 Mar 2023 Paper 12 Q15
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Correct answer: B
Question 2 — IGCSE 0653 Mar 2023 Paper 12 Q16
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Correct answer: C
Question 3 — IGCSE 0653 Mar 2023 Paper 12 Q17
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Correct answer: A
Question 4 — IGCSE 0653 May/Jun 2023 Paper 13 Q17
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Correct answer: A
Question 5 — IGCSE 0653 May/Jun 2023 Paper 13 Q18
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Correct answer: B
Question 6 — IGCSE 0653 May/Jun 2023 Paper 11 Q19
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Correct answer: C
Question 7 — IGCSE 0653 May/Jun 2023 Paper 12 Q19
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Correct answer: B
Question 8 — IGCSE 0653 May/Jun 2023 Paper 13 Q19
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Correct answer: D
Question 9 — IGCSE 0653 May/Jun 2023 Paper 11 Q20
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Correct answer: C
Question 10 — IGCSE 0653 May/Jun 2023 Paper 12 Q20
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Correct answer: B
Question 11 — IGCSE 0653 May/Jun 2023 Paper 11 Q21
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Correct answer: A
Question 12 — IGCSE 0653 May/Jun 2023 Paper 12 Q21
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Correct answer: B
Question 13 — IGCSE 0653 May/Jun 2023 Paper 11 Q22
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Correct answer: D
Question 14 — IGCSE 0653 Oct/Nov 2023 Paper 11 Q16
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Correct answer: C
Question 15 — IGCSE 0653 Oct/Nov 2023 Paper 11 Q17
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Correct answer: A
Question 16 — IGCSE 0653 Oct/Nov 2023 Paper 12 Q17
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Correct answer: B
Question 17 — IGCSE 0653 Oct/Nov 2023 Paper 13 Q17
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Correct answer: B
Question 18 — IGCSE 0653 Oct/Nov 2023 Paper 11 Q18
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Correct answer: C
Question 19 — IGCSE 0653 Oct/Nov 2023 Paper 12 Q18
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Correct answer: C
Question 20 — IGCSE 0653 Oct/Nov 2023 Paper 13 Q18
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Correct answer: C
Question 21 — IGCSE 0653 Oct/Nov 2023 Paper 11 Q19
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Correct answer: B
Question 22 — IGCSE 0653 Oct/Nov 2023 Paper 12 Q19
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Correct answer: A
Question 23 — IGCSE 0653 Oct/Nov 2023 Paper 13 Q19
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Correct answer: A
Chemical Energetics — Extended MCQ32 · Paper 2
Question 1 — IGCSE 0653 Mar 2023 Paper 22 Q16
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Correct answer: C
Question 2 — IGCSE 0653 Mar 2023 Paper 22 Q17
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Correct answer: A
Question 3 — IGCSE 0653 Mar 2023 Paper 22 Q18
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Correct answer: A
Question 4 — IGCSE 0653 Mar 2024 Paper 22 Q20
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Correct answer: D
Question 5 — IGCSE 0653 Mar 2024 Paper 22 Q21
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Correct answer: C
Question 6 — IGCSE 0653 Mar 2025 Paper 22 Q18
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Correct answer: C
Question 7 — IGCSE 0653 Mar 2025 Paper 22 Q19
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Correct answer: D
Question 8 — IGCSE 0653 Mar 2025 Paper 22 Q20
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Correct answer: B
Question 9 — IGCSE 0653 May/Jun 2023 Paper 23 Q16
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Correct answer: B
Question 10 — IGCSE 0653 May/Jun 2023 Paper 23 Q17
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Correct answer: B
Question 11 — IGCSE 0653 May/Jun 2023 Paper 23 Q18
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Correct answer: B
Question 12 — IGCSE 0653 May/Jun 2023 Paper 23 Q19
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Correct answer: B
Question 13 — IGCSE 0653 May/Jun 2024 Paper 21 Q19
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Correct answer: C
Question 14 — IGCSE 0653 May/Jun 2024 Paper 22 Q19
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Correct answer: D
Question 15 — IGCSE 0653 May/Jun 2024 Paper 21 Q20
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Correct answer: C
Question 16 — IGCSE 0653 May/Jun 2024 Paper 22 Q20
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Correct answer: A
Question 17 — IGCSE 0653 May/Jun 2024 Paper 21 Q21
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Correct answer: D
Question 18 — IGCSE 0653 May/Jun 2024 Paper 22 Q21
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Correct answer: C
Question 19 — IGCSE 0653 May/Jun 2025 Paper 22 Q16
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Correct answer: A
Question 20 — IGCSE 0653 May/Jun 2025 Paper 22 Q17
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Correct answer: D
Question 21 — IGCSE 0653 May/Jun 2025 Paper 22 Q18
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Correct answer: B
Question 22 — IGCSE 0653 May/Jun 2025 Paper 22 Q19
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Correct answer: B
Question 23 — IGCSE 0653 May/Jun 2025 Paper 22 Q20
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Correct answer: B
Question 24 — IGCSE 0653 Oct/Nov 2023 Paper 22 Q15
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Correct answer: D
Question 25 — IGCSE 0653 Oct/Nov 2023 Paper 22 Q16
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Correct answer: D
Question 26 — IGCSE 0653 Oct/Nov 2023 Paper 22 Q17
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Correct answer: B
Question 27 — IGCSE 0653 Oct/Nov 2023 Paper 23 Q17
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Correct answer: B
Question 28 — IGCSE 0653 Oct/Nov 2023 Paper 22 Q18
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Correct answer: B
Question 29 — IGCSE 0653 Oct/Nov 2023 Paper 23 Q18
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Correct answer: C
Question 30 — IGCSE 0653 Oct/Nov 2023 Paper 21 Q19
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Correct answer: D
Question 31 — IGCSE 0653 Oct/Nov 2023 Paper 21 Q20
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Correct answer: C
Question 32 — IGCSE 0653 Oct/Nov 2023 Paper 21 Q21
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Correct answer: D
All Chemical Energetics questions in this collection
| Type | Level | Paper | Session | Q# | Marks | Answer / key |
|---|---|---|---|---|---|---|
| MCQ | Core | Paper 12 | Mar 2023 | Q15 | 1 mark | B |
| MCQ | Core | Paper 12 | Mar 2023 | Q16 | 1 mark | C |
| MCQ | Core | Paper 12 | Mar 2023 | Q17 | 1 mark | A |
| MCQ | Core | Paper 13 | May/Jun 2023 | Q17 | 1 mark | A |
| MCQ | Core | Paper 13 | May/Jun 2023 | Q18 | 1 mark | B |
| MCQ | Core | Paper 11 | May/Jun 2023 | Q19 | 1 mark | C |
| MCQ | Core | Paper 12 | May/Jun 2023 | Q19 | 1 mark | B |
| MCQ | Core | Paper 13 | May/Jun 2023 | Q19 | 1 mark | D |
| MCQ | Core | Paper 11 | May/Jun 2023 | Q20 | 1 mark | C |
| MCQ | Core | Paper 12 | May/Jun 2023 | Q20 | 1 mark | B |
| MCQ | Core | Paper 11 | May/Jun 2023 | Q21 | 1 mark | A |
| MCQ | Core | Paper 12 | May/Jun 2023 | Q21 | 1 mark | B |
| MCQ | Core | Paper 11 | May/Jun 2023 | Q22 | 1 mark | D |
| MCQ | Core | Paper 11 | Oct/Nov 2023 | Q16 | 1 mark | C |
| MCQ | Core | Paper 11 | Oct/Nov 2023 | Q17 | 1 mark | A |
| MCQ | Core | Paper 12 | Oct/Nov 2023 | Q17 | 1 mark | B |
| MCQ | Core | Paper 13 | Oct/Nov 2023 | Q17 | 1 mark | B |
| MCQ | Core | Paper 11 | Oct/Nov 2023 | Q18 | 1 mark | C |
| MCQ | Core | Paper 12 | Oct/Nov 2023 | Q18 | 1 mark | C |
| MCQ | Core | Paper 13 | Oct/Nov 2023 | Q18 | 1 mark | C |
| MCQ | Core | Paper 11 | Oct/Nov 2023 | Q19 | 1 mark | B |
| MCQ | Core | Paper 12 | Oct/Nov 2023 | Q19 | 1 mark | A |
| MCQ | Core | Paper 13 | Oct/Nov 2023 | Q19 | 1 mark | A |
| MCQ | Extended | Paper 22 | Mar 2023 | Q16 | 1 mark | C |
| MCQ | Extended | Paper 22 | Mar 2023 | Q17 | 1 mark | A |
| MCQ | Extended | Paper 22 | Mar 2023 | Q18 | 1 mark | A |
| MCQ | Extended | Paper 22 | Mar 2024 | Q20 | 1 mark | D |
| MCQ | Extended | Paper 22 | Mar 2024 | Q21 | 1 mark | C |
| MCQ | Extended | Paper 22 | Mar 2025 | Q18 | 1 mark | C |
| MCQ | Extended | Paper 22 | Mar 2025 | Q19 | 1 mark | D |
| MCQ | Extended | Paper 22 | Mar 2025 | Q20 | 1 mark | B |
| MCQ | Extended | Paper 23 | May/Jun 2023 | Q16 | 1 mark | B |
| MCQ | Extended | Paper 23 | May/Jun 2023 | Q17 | 1 mark | B |
| MCQ | Extended | Paper 23 | May/Jun 2023 | Q18 | 1 mark | B |
| MCQ | Extended | Paper 23 | May/Jun 2023 | Q19 | 1 mark | B |
| MCQ | Extended | Paper 21 | May/Jun 2024 | Q19 | 1 mark | C |
| MCQ | Extended | Paper 22 | May/Jun 2024 | Q19 | 1 mark | D |
| MCQ | Extended | Paper 21 | May/Jun 2024 | Q20 | 1 mark | C |
| MCQ | Extended | Paper 22 | May/Jun 2024 | Q20 | 1 mark | A |
| MCQ | Extended | Paper 21 | May/Jun 2024 | Q21 | 1 mark | D |
| MCQ | Extended | Paper 22 | May/Jun 2024 | Q21 | 1 mark | C |
| MCQ | Extended | Paper 22 | May/Jun 2025 | Q16 | 1 mark | A |
| MCQ | Extended | Paper 22 | May/Jun 2025 | Q17 | 1 mark | D |
| MCQ | Extended | Paper 22 | May/Jun 2025 | Q18 | 1 mark | B |
| MCQ | Extended | Paper 22 | May/Jun 2025 | Q19 | 1 mark | B |
| MCQ | Extended | Paper 22 | May/Jun 2025 | Q20 | 1 mark | B |
| MCQ | Extended | Paper 22 | Oct/Nov 2023 | Q15 | 1 mark | D |
| MCQ | Extended | Paper 22 | Oct/Nov 2023 | Q16 | 1 mark | D |
| MCQ | Extended | Paper 22 | Oct/Nov 2023 | Q17 | 1 mark | B |
| MCQ | Extended | Paper 23 | Oct/Nov 2023 | Q17 | 1 mark | B |
| MCQ | Extended | Paper 22 | Oct/Nov 2023 | Q18 | 1 mark | B |
| MCQ | Extended | Paper 23 | Oct/Nov 2023 | Q18 | 1 mark | C |
| MCQ | Extended | Paper 21 | Oct/Nov 2023 | Q19 | 1 mark | D |
| MCQ | Extended | Paper 21 | Oct/Nov 2023 | Q20 | 1 mark | C |
| MCQ | Extended | Paper 21 | Oct/Nov 2023 | Q21 | 1 mark | D |
| Theory | Core | Paper 31 | May/Jun 2023 | Q2 | 10 marks | thermometer |
| Theory | Extended | Paper 43 | May/Jun 2024 | Q2 | 8 marks | activation energy correctly labelled on both diagrams |
| Theory | Extended | Paper 41 | May/Jun 2024 | Q5 | 8 marks | activation energy shown as a maximum between reactants and products |
| Theory | Extended | Paper 42 | May/Jun 2024 | Q5 | 6 marks | (overall) energy change is endothermic or more energy taken in than given out |
| Theory | Extended | Paper 41 | Oct/Nov 2023 | Q5 | 9 marks | > 0 to < 20 (°C) |