Pearson Edexcel International GCSE in Chemistry · 4CH1 · Free · no account needed
Alkanes — exam questions
12 original Incandio exam-style questions on alkanes, 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 Alkanes — 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
- State what is meant by (1–2 marks)
- the definition
- Give (1–2 marks)
- a short factual answer — the most common chemistry command
- Determine (1–4 marks)
- a value reached by combining given data with a method the learner selects
- 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
- Suggest (1–3 marks)
- a plausible answer applying taught chemistry to an unfamiliar substance
- Complete (1–4 marks)
- the missing entries in a table, equation or diagram
- 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
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 4.19 · 4.20 · 4.22 · 4.21. 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 — the first five alkanes Name Molecular formula Boiling point / °C methane CH₄ −162 ethane C₂H₆ −89 propane C₃H₈ −42 butane C₄H₁₀ −1 pentane to be found 36 (a)
(1)Complete
Complete Table 1 by giving the molecular formula of pentane.
Table 1 — the first five alkanes Name Molecular formula Boiling point / °C methane CH₄ −162 ethane C₂H₆ −89 propane C₃H₈ −42 butane C₄H₁₀ −1 pentane to be found 36 (b)
(2)Describe
Describe the trend in boiling point shown in Table 1.
Table 1 — the first five alkanes Name Molecular formula Boiling point / °C methane CH₄ −162 ethane C₂H₆ −89 propane C₃H₈ −42 butane C₄H₁₀ −1 pentane to be found 36 (c)
(3)Explain
Explain the trend in Table 1 in terms of the forces between molecules.
Table 1 — the first five alkanes Name Molecular formula Boiling point / °C methane CH₄ −162 ethane C₂H₆ −89 propane C₃H₈ −42 butane C₄H₁₀ −1 pentane to be found 36 (d)
(3)Suggest
Table 1 gives one boiling point for each alkane, but pentane has three isomers. Suggest what this shows about the table.
Table 1 — the first five alkanes Name Molecular formula Boiling point / °C methane CH₄ −162 ethane C₂H₆ −89 propane C₃H₈ −42 butane C₄H₁₀ −1 pentane to be found 36 (Total for Question 1 = 9 marks)
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(1)Which
Which is the general formula for the alkanes?
Formula A CₙH₂ₙ B CₙH₂ₙ₊₂ C CₙH₂ₙ₋₂ D CₙH₂ₙ₊₁OH (Total for Question 2 = 1 mark)
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(1)State what is meant by
State what is meant by a saturated hydrocarbon.
(Total for Question 3 = 1 mark)
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(1)Give
Give the condition needed for an alkane to react with a halogen.
(Total for Question 4 = 1 mark)
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(2)Determine
A hydrocarbon molecule contains five carbon atoms and ten hydrogen atoms. Determine whether it is an alkane, and give a reason.
(Total for Question 5 = 2 marks)
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(2)Write
Write the equation for the reaction between ethane and chlorine in ultraviolet light, limited to one substitution.
(Total for Question 6 = 2 marks)
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(3)Explain
Explain why an alkane cannot take part in an addition reaction.
(Total for Question 7 = 3 marks)
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(3)Suggest
Suggest why the reaction between methane and chlorine is not a useful way to prepare a pure sample of chloromethane.
(Total for Question 8 = 3 marks)
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(4)Explain
Explain why alkanes are described as saturated, and why their boiling points rise as the chains get longer.
(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 alkanes to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Jean-Baptiste Dumas over three rounds, marked against descriptors you can read first.
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Back to the lesson
- Alkanes — The family that is already full — what saturation means, and the one reaction that gets past it.
- All of Incandio Chemistry · Incandio Exam Practice