Pearson Edexcel International GCSE in Chemistry · 4CH1 · Free · no account needed
Alkene Reactions And The Bromine Test — exam questions
12 original Incandio exam-style questions on Alkene Reactions And The Bromine Test, 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 Alkene Reactions And The Bromine Test — 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
9 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
- Give (1–2 marks)
- a short factual answer — the most common chemistry command
- Name (1 mark)
- the correct chemical name
- Write (1–3 marks)
- the equation, formula or ionic equation, balanced, with state symbols where asked
- 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
- Determine (1–4 marks)
- a value reached by combining given data with a method the learner selects
- 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
- Compare (2–4 marks)
- explicit comparison with a comparative word — a bare pair of statements is not a comparison
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 4.28 · 4.27. 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 — bromine water added to four hydrocarbons and shaken Tube Hydrocarbon Formula Observation 1 ethane C₂H₆ stays orange-brown 2 ethene C₂H₄ decolourises at once 3 propane C₃H₈ stays orange-brown 4 unknown gas X C₄H₈ to be predicted (a)
(1)Identify
Identify the tube in Table 1 containing an unsaturated hydrocarbon.
Table 1 — bromine water added to four hydrocarbons and shaken Tube Hydrocarbon Formula Observation 1 ethane C₂H₆ stays orange-brown 2 ethene C₂H₄ decolourises at once 3 propane C₃H₈ stays orange-brown 4 unknown gas X C₄H₈ to be predicted (b)
(2)Explain
Explain why tubes 1 and 3 in Table 1 give the same result.
Table 1 — bromine water added to four hydrocarbons and shaken Tube Hydrocarbon Formula Observation 1 ethane C₂H₆ stays orange-brown 2 ethene C₂H₄ decolourises at once 3 propane C₃H₈ stays orange-brown 4 unknown gas X C₄H₈ to be predicted (c)
(3)Suggest
Suggest what would be observed in tube 4 of Table 1, and explain your prediction from the formula.
Table 1 — bromine water added to four hydrocarbons and shaken Tube Hydrocarbon Formula Observation 1 ethane C₂H₆ stays orange-brown 2 ethene C₂H₄ decolourises at once 3 propane C₃H₈ stays orange-brown 4 unknown gas X C₄H₈ to be predicted (d)
(3)Suggest
Suggest why the student should shake each tube for the same length of time before recording the result.
Table 1 — bromine water added to four hydrocarbons and shaken Tube Hydrocarbon Formula Observation 1 ethane C₂H₆ stays orange-brown 2 ethene C₂H₄ decolourises at once 3 propane C₃H₈ stays orange-brown 4 unknown gas X C₄H₈ to be predicted (Total for Question 1 = 9 marks)
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(1)Which
Which is seen when bromine water is shaken with an alkene?
Observation A it turns from colourless to orange-brown B it decolourises C it turns milky D no change (Total for Question 2 = 1 mark)
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(1)Give
Give the colour of bromine water before it is used.
(Total for Question 3 = 1 mark)
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(1)Name
Name the type of reaction between an alkene and bromine.
(Total for Question 4 = 1 mark)
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(2)Write
Write the equation for the reaction between ethene and bromine.
(Total for Question 5 = 2 marks)
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(3)Explain
Explain why bromine water decolourises with an alkene but not with an alkane.
(Total for Question 6 = 3 marks)
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(2)Determine
Determine the name of the product formed when propene reacts with bromine, and explain how the name is arrived at.
(Total for Question 7 = 2 marks)
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(3)Suggest
A student says the bromine test proves a gas is ethene. Suggest why the test cannot show that.
(Total for Question 8 = 3 marks)
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(4)Compare
Compare what happens when bromine water is shaken with hexane and when it is shaken with hexene.
(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 Alkene Reactions And The Bromine Test to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Emil Erlenmeyer over three rounds, marked against descriptors you can read first.
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Back to the lesson
- Alkene Reactions And The Bromine Test — The double bond opens, both bromine atoms join on, and an orange colour disappears — which is how you tell the two families apart.
- All of Incandio Chemistry · Incandio Exam Practice