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Butene reacts with steam to produce butanol - Edexcel - GCSE Chemistry Combined Science - Question 5 - 2016 - Paper 1
Question 5
Butene reacts with steam to produce butanol. C₄H₈ + H₂O → C₄H₉OH (i) Calculate the maximum mass of butanol, C₄H₉OH, that can be produced when 1.4 kg of butene, C₄H... show full transcript
Worked Solution & Example Answer:Butene reacts with steam to produce butanol - Edexcel - GCSE Chemistry Combined Science - Question 5 - 2016 - Paper 1
Step 1
Calculate the maximum mass of butanol, C₄H₉OH, that can be produced when 1.4 kg of butene, C₄H₈, reacts with excess steam.
Answer
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First, we should find the number of moles of butene, C₄H₈:
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The reaction produces 1 mole of butanol for every mole of butene consumed. This means that 25 moles of butene will produce 25 moles of butanol.
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Next, calculate the mass of butanol produced:
The molar mass of butanol (C₄H₉OH):
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Carbon: 4 × 12 = 48
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Hydrogen: 10 × 1 = 10
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Oxygen: 1 × 16 = 16
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Then, substituting the values:
Step 2
What type of reaction takes place between butene and steam?
Answer
The reaction that occurs between butene and steam is a dehydration reaction. This can be concluded from the following options:
- A: addition – NOT correct, since this does not accurately describe the formation of butanol.
- B: dehydration – CORRECT, as steam reacts with butene under specific conditions to create an alcohol.
- C: neutralisation – NOT applicable, since no acid-base reaction is involved.
- D: substitution – INCORRECT, as it does not involve substituting one functional group for another.
Step 3
Using the results, comment on the structures of the hydrocarbons X, Y and Z.
Answer
For the results obtained from the bromine water tests:
- Hydrocarbon X turns the orange bromine water colourless, indicating it could be an alkene or an unsaturated compound, as it reacts with bromine.
- Hydrocarbon Y also turns the bromine water colourless, suggesting it has similar unsaturation or reactivity as hydrocarbon X.
- Hydrocarbon Z does not react with bromine water and therefore maintains the orange colour, indicating that it is likely a saturated hydrocarbon, such as an alkane, which does not undergo reaction with bromine.