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Crude oil is a mixture of hydrocarbons - Edexcel - GCSE Chemistry Combined Science - Question 6 - 2023 - Paper 2
Question 6
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. Figur... show full transcript
Worked Solution & Example Answer:Crude oil is a mixture of hydrocarbons - Edexcel - GCSE Chemistry Combined Science - Question 6 - 2023 - Paper 2
Step 1
Step 2
Explain the trend in the viscosity of the fractions.
Answer
The trend in viscosity is that it increases with increasing molecular weight and size of the hydrocarbon chains present in the fractions.
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Gases and petrol have the lowest viscosity due to their lower molecular weights and relatively short chain lengths.
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Kerosene has a higher viscosity than petrol, reflecting its larger molecule size.
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Diesel oil exhibits even higher viscosity due to even larger hydrocarbon molecules.
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Fuel oil and bitumen have the highest viscosity since they contain the largest and heaviest hydrocarbon chains.
This trend can be attributed to the increase in intermolecular forces as molecular weights increase, causing liquids to resist flow more effectively.