Crude oil is a mixture of hydrocarbons - Edexcel - GCSE Chemistry - Question 9 - 2023 - Paper 2
Question 9
Crude oil is a mixture of hydrocarbons.
Crude oil can be separated into useful fractions by the process of fractional distillation in a fractionating column.
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Worked Solution & Example Answer:Crude oil is a mixture of hydrocarbons - Edexcel - GCSE Chemistry - Question 9 - 2023 - Paper 2
Step 1
Which row shows the correct uses for bitumen, diesel oil and fuel oil?
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Answer
The correct answer is C: surfacing roads, fuel for trains, fuel for large ships. Bitumen is primarily used for road surfacing, while diesel oil and fuel oil have different applications.
Step 2
Explain the trend in the viscosity of the fractions.
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Answer
Viscosity increases down the column as the molecular size increases. Larger hydrocarbon molecules have stronger intermolecular forces due to increased surface area of contact, resulting in greater resistance to flow.
Step 3
Deduce the molecular formula of hydrocarbon X.
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Answer
Given that the relative formula mass of Y is 56 and the empirical formula of Y is C₂H₄, we can determine that Y is C₄H₈ (since 56 / 14 = 4).
For hydrocarbon X, we note that it forms one molecule of C₆H₁₄ (hexane) and one molecule of C₄H₈. Thus, the total number of carbons and hydrogens in X is:
