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Fractional distillation is used to separate crude oil into fractions - Edexcel - GCSE Chemistry - Question 1 - 2012 - Paper 1
Question 1
Fractional distillation is used to separate crude oil into fractions. A fractionating column is used for the process. The diagram shows a fractionating column and th... show full transcript
Worked Solution & Example Answer:Fractional distillation is used to separate crude oil into fractions - Edexcel - GCSE Chemistry - Question 1 - 2012 - Paper 1
Step 1
Which of the following statements is true?
Answer
The true statement among the options provided is C: Diesel oil is denser than molecules in petrol.
Explanation:
- Fuel oils typically have higher boiling points compared to lighter fuels like petrol, thus A is false.
- Kerosene is less viscous than petrol; therefore, B is inaccurate.
- Diesel oil molecules are larger and denser than those of petrol, supporting option C.
- Generally, diesel is less volatile than petrol, making D incorrect as well.
Step 2
Explain what is meant by cracking.
Answer
Cracking is a chemical process used to break down larger, more complex hydrocarbon molecules into simpler, smaller molecules, usually alkenes and smaller alkanes.
Process:
- Thermal Cracking: This method involves heating the hydrocarbons to high temperatures (around 450-750°C) and applying high pressure, causing the long-chain hydrocarbons to break apart.
- Catalytic Cracking: In this method, a catalyst reduces the required temperature and pressure, increasing efficiency and yield of valuable products such as gasoline and olefins.
Cracking is essential in the petroleum industry to maximize the yield of useful products from crude oil.