Pearson Edexcel International GCSE in Chemistry · 4CH1 · Free · no account needed
Exothermic and Endothermic Reactions — exam questions
12 original Incandio exam-style questions on Exothermic and Endothermic Reactions, 26 marks, about 26 minutes of writing. Each one carries the command word, the tariff and the specification statement it assesses, exactly as a paper presents them. This is an original Incandio practice question, written to reflect the structure and demands of the qualification. It is not an official Pearson Edexcel past-paper question.
This is the practice set for Exothermic and Endothermic Reactions — the lesson that teaches it. Read the lesson first if the idea is new; come here when you want to find out whether you can turn it into marks. Completely free, no account needed to read.
What these questions ask of you
8 command words run through this set, and on Pearson Edexcel International GCSE Chemistry each one means something precise. Answering the wrong command is the commonest way a candidate who understands the lesson still loses the mark.
- Which (1 mark)
- one option chosen from the set given
- State what is meant by (1–2 marks)
- the definition
- Give (1–2 marks)
- a short factual answer — the most common chemistry command
- Describe (2–5 marks)
- developed, linked statements of what happens or what is observed Misread as: giving one bare observation where the tariff asked for a developed account
- Explain (2–4 marks)
- the reason, in terms of particles, bonding, energy or equilibrium Misread as: describing the observation without giving the chemistry that causes it
- Suggest (1–3 marks)
- a plausible answer applying taught chemistry to an unfamiliar substance
- Identify (1–2 marks)
- the correct substance or feature selected from what is given
- Calculate (1–4 marks)
- a numerical answer with working, to the stated precision
Assessed on Paper 1 (4CH1/1C) and Paper 2 (4CH1/2C), against AO1, AO2, AO3.
Where these sit in the specification
Pearson Edexcel International GCSE Chemistry (4CH1) — statements 3.1 · 3.2 · 3.8. Incandio is aligned to this specification; it is not published by, endorsed by or affiliated with Pearson, and it reproduces none of Pearson's wording.
The 12 questions
Answer them on paper, then open the lesson's exam practice to have them marked. The mark scheme, the accepted and rejected answers and the annotated model answer are in Incandio and are not printed here — an answer beside its question is not practice.
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Table 1 — temperature change when four solids were stirred into 50 cm³ of water Solid Start temperature / °C Final temperature / °C calcium chloride 20.5 34.2 ammonium nitrate 20.5 12.8 sodium hydroxide 20.5 31.6 sodium chloride 20.5 20.3 (a)
(1)Identify
Identify the solid in Table 1 whose dissolving is endothermic.
Table 1 — temperature change when four solids were stirred into 50 cm³ of water Solid Start temperature / °C Final temperature / °C calcium chloride 20.5 34.2 ammonium nitrate 20.5 12.8 sodium hydroxide 20.5 31.6 sodium chloride 20.5 20.3 (b)
(2)Calculate
Calculate the temperature change for calcium chloride and for ammonium nitrate in Table 1.
Table 1 — temperature change when four solids were stirred into 50 cm³ of water Solid Start temperature / °C Final temperature / °C calcium chloride 20.5 34.2 ammonium nitrate 20.5 12.8 sodium hydroxide 20.5 31.6 sodium chloride 20.5 20.3 (c)
(3)Explain
Explain what the result for sodium chloride in Table 1 shows about dissolving it.
Table 1 — temperature change when four solids were stirred into 50 cm³ of water Solid Start temperature / °C Final temperature / °C calcium chloride 20.5 34.2 ammonium nitrate 20.5 12.8 sodium hydroxide 20.5 31.6 sodium chloride 20.5 20.3 (d)
(3)Suggest
Suggest two improvements to the experiment in Table 1 that would make the comparison between the four solids fairer.
Table 1 — temperature change when four solids were stirred into 50 cm³ of water Solid Start temperature / °C Final temperature / °C calcium chloride 20.5 34.2 ammonium nitrate 20.5 12.8 sodium hydroxide 20.5 31.6 sodium chloride 20.5 20.3 (Total for Question 1 = 9 marks)
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(1)Which
Which happens to the temperature of the surroundings during an exothermic reaction?
Change A it rises B it falls C it stays the same D it falls and then rises (Total for Question 2 = 1 mark)
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(1)State what is meant by
State what is meant by an endothermic reaction.
(Total for Question 3 = 1 mark)
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(1)Give
Give one example of an exothermic reaction.
(Total for Question 4 = 1 mark)
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(2)Describe
Describe how a simple experiment could show whether dissolving a solid in water is exothermic or endothermic.
(Total for Question 5 = 2 marks)
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(3)Explain
Explain why the temperature of the surroundings falls during an endothermic reaction.
(Total for Question 6 = 3 marks)
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(2)Explain
Explain why a polystyrene cup with a lid is used rather than a glass beaker in these experiments.
(Total for Question 7 = 2 marks)
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(3)Suggest
A sports injury pack contains two sealed compartments that are burst together to make the pack go cold. Suggest what happens inside it, in terms of energy.
(Total for Question 8 = 3 marks)
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(4)Explain
A hand warmer works by crystallising a supersaturated salt solution. Explain why this warms the hand and why the pack can be reset by boiling it.
(Total for Question 9 = 4 marks)
Have them marked, then defend the answer
Practice tells you the mark; teaching it back tells you whether you understand it. On Incandio a topic counts as mastered only once you have taught it and defended it.
- Mark these questions — 12 questions, marked on Incandio against the authored scheme, with the mistake you actually made named.
- Teach it — explain Exothermic and Endothermic Reactions to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Marcellin Berthelot over three rounds, marked against descriptors you can read first.
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Back to the lesson
- Exothermic and Endothermic Reactions — Reactions that warm their surroundings and reactions that chill them — and why the thermometer tells you which.
- All of Incandio Chemistry · Incandio Exam Practice