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Butene reacts with steam to produce butanol - Edexcel - GCSE Chemistry - Question 5 - 2016 - Paper 1
Question 5
Butene reacts with steam to produce butanol. C₄H₁₀ + H₂O → C₄H₉OH (i) Calculate the maximum mass of butanol, C₄H₉OH, that can be produced when 1.4 kg of butene, C₄... show full transcript
Worked Solution & Example Answer:Butene reacts with steam to produce butanol - Edexcel - GCSE Chemistry - Question 5 - 2016 - Paper 1
Step 1
Calculate the maximum mass of butanol, C₄H₉OH
Answer
To calculate the maximum mass of butanol that can be produced from butene, we start by calculating the number of moles of butene:
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Molar mass of butene, C₄H₁₀:
C: 12 g/mol × 4 = 48 g/mol H: 1 g/mol × 10 = 10 g/mol Total = 48 g/mol + 10 g/mol = 58 g/mol
Therefore, the molar mass of butene is 58 g/mol.
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1.4 kg of butene:
1.4 kg = 1400 g Moles of butene = mass / molar mass = 1400 g / 58 g/mol ≈ 24.14 moles.
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The balanced equation shows that 1 mole of butene produces 1 mole of butanol:
C₄H₁₀ + H₂O → C₄H₉OH
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Therefore, the moles of butanol produced is also 24.14 moles.
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Molar mass of butanol, C₄H₉OH:
C: 12 g/mol × 4 = 48 g/mol H: 1 g/mol × 10 = 10 g/mol O: 16 g/mol × 1 = 16 g/mol Total = 48 g/mol + 10 g/mol + 16g/mol = 74 g/mol
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Finally, calculate the mass of butanol produced:
Mass of butanol = moles × molar mass = 24.14 moles × 74 g/mol = 1787.36 g = 1.79 kg.
Thus, the maximum mass of butanol that can be produced is approximately 1.79 kg.
Step 2
What type of reaction takes place between butene and steam?
Answer
The reaction between butene and steam is classified as:
B: dehydration.
In this case, steam (water vapor) is added across the double bond of butene, resulting in the formation of butanol. Since this process involves the addition of water to the alkene, it also fits the definition of an addition reaction.
Step 3
Using the results, comment on the structures of the hydrocarbons X, Y and Z.
Answer
In the results observed with bromine water:
- Hydrocarbon X and hydrocarbon Y both cause the bromine water to turn colourless, indicating that they are likely alkenes or compounds that can react with bromine (adding across double bonds).
- Hydrocarbon Z, which does not change the color of the bromine water, suggests that it is a saturated hydrocarbon, such as an alkane, which does not react with bromine.
Thus, we can conclude the following:
- X and Y are likely unsaturated hydrocarbons (alkenes), while Z is likely a saturated hydrocarbon (alkane).