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Global challenges

OCR GCSE Combined ScienceTopic 12 of 1820 lessons

Revision notes for Global challenges in OCR Combined Science A (J250). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.

  1. Extracting metals using carbonMost metals are found in the Earth's crust as compounds, usually oxides, mixed with rock.
  2. Extracting metals by electrolysisMetals that are more reactive than carbon cannot be extracted by heating with carbon, so they are extracted by electrolysis.
  3. Bacterial and phytoextraction of metalsTraditional extraction needs ores that contain a lot of metal, and it uses large amounts of energy.
  4. Life-cycle assessmentA life-cycle assessment looks at the impact of a material or product on the environment over its whole life, from the start to the end.
  5. Interpreting life-cycle assessment dataLife-cycle assessment data is often given in a table with one column for each product and one row for each stage.
  6. Recycling a material for a different useRecycling means processing a used material so that it can be made into new products instead of being thrown away.
  7. Recycling decisionsRecycling means collecting used materials such as metals, glass, paper and plastics and turning them into new products.
  8. Fractional distillation of crude oilCrude oil is a mixture of many hydrocarbons.
  9. Why fractions separateHydrocarbons are made of small covalent molecules.
  10. Alkanes in the fractionsA hydrocarbon is a compound that contains only hydrogen and carbon atoms.
  11. Crude oil as a source of hydrocarbonsCrude oil is a mixture of hydrocarbons, and it is the main source of hydrocarbons that we use.
  12. Dependence on hydrocarbonsModern life depends heavily on hydrocarbons from crude oil.
  13. Cracking hydrocarbonsFractional distillation gives more long-chain hydrocarbons than industry needs, and fewer short-chain ones, which are more useful as fuels.
  14. Evidence for the early atmosphereThe Earth is about 4.6 billion years old, and no one was there to record the first atmosphere.
  15. How an oxygen-rich atmosphere developedThe early atmosphere had almost no oxygen.
  16. The greenhouse effectThe Sun gives out radiation, mostly visible light and ultraviolet radiation, which has a short wavelength.
  17. Human causes of climate changeEvidence shows that the amount of carbon dioxide in the atmosphere has risen sharply since the Industrial Revolution, and so has the average global…
  18. Effects of greenhouse gases and how to reduce themCarbon dioxide and methane are greenhouse gases.
  19. Air pollutants and their problemsBurning fuels can release harmful pollutants.
  20. Making potable waterPotable water is water that is safe to drink.

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