AQA · Chemistry · 8462

GCSE Chemistry (AQA): Fractional Distillation

Topic 7 — Organic Chemistry. Generated from the caption track of Cognito's lesson video "GCSE Chemistry - Fractional Distillation - Crude Oil | Hydrocarbons (2027/28 exams)"; each card deep-links to the moment in the video it came from. Lesson 7.06 of Cognito's AQA GCSE Combined Science (Trilogy) and Chemistry course (Higher tier), filed under AQA Chemistry 8462. Teaching by Cognito — https://cognitoedu.org/coursesubtopic/c2-gcse-aqa-h-c_7.06.

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  1. What does it mean to use petrochemicals as feedstock?

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    Using them as raw materials for the petrochemical industry, to make products such as solvents, lubricants, polymers and detergents.

  2. Which two gases make up most of LPG?

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    Propane and butane — very short-chain alkanes with boiling points low enough to stay gaseous throughout the column.

  3. Which type of hydrocarbon is most common in crude oil?

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    Alkanes.

  4. Because it takes millions of years to form, crude oil is a ? resource.

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    finite

  5. Which crude oil fraction is used as fuel in jet engines?

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    Kerosene.

  6. Which property of hydrocarbons does fractional distillation exploit to separate them?

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    Their different boiling points.

  7. Which fraction of crude oil is used to surface roads?

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    Bitumen — a very long-chain fraction collected at the bottom of the column.

  8. What conditions turned buried biomass into crude oil?

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    High pressure and high temperature underground over millions of years.

  9. How does temperature vary inside a fractionating column?

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    It is hottest at the bottom and gets cooler towards the top.

  10. What is the name of the process that breaks long-chain hydrocarbons into smaller ones?

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    Cracking.

  11. Which two elements does a hydrocarbon contain?

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    Hydrogen and carbon only.

  12. Why do long-chain hydrocarbons condense near the bottom of the fractionating column?

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    They have the highest boiling points, so they condense as soon as they meet a temperature below that boiling point — which happens low down.

  13. What is crude oil made from?

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    The remains of dead plants and animals, especially plankton, that were buried in mud millions of years ago.

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