C1.5- Products from Oil

- Cracking hydrocarbons

- Making polymers from alkenes

- New and useful polymers

- Plastic waste

- Ethanol

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Cracking Hydrocarbons (C1.5.1)

Heavier fractions are not very useful (they do not burn easily - can not be used as fuels) so we use a indistrial process called cracking to break apart the long chain alkanes, to produce short chain ones, which can be used as fuels.

Cracking;

  • Heavy crude oil fraction is vaporised (extremely high temperatures)
  • It is then EITHER passed over a hot catalyst, or mixed with steam.
  • Cracking produces a short chain alkane and a alkene.

long chain alkane ---> short chain alkane + alkene

Alkenes;

  • Unsaturated hydrocarbons
  • have one double carbon bond
  • CnH2n
  • bromine test- POSITIVE
  • orange colour ---> colourless
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Making polymers from alkenes (C1.5.2)

  • Crude oil can also be used to make chemicals
  • Important use = making plastics
  • Plastics are made of polymers

Polymers = a large molecule made from repeating units of monomers

Monomers = small reactive molecules that react together in repeating sequences to                        form polymers

Uses;

  • Poly(ethene) = plastic bags, drink bottles, cling film (easy to shape, strong)
  • Poly(propene) = carpet, milk trays, rope (strong, tough)

Polymerisation (creating polymers)

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New and Useful Polymers (C1.5.3)

New polymers are being developed for specific purposes;

  • ie; response to light (light sensitive plasters)
  • ie; response to temperature (shape memory stitches)

New Uses;

  • PET is a polymer used to make drinks bottles
  • It is now also used to make clothes

Hydrogels;

  • Polymer chains with a few cross linking units (between chains)
  • This creates a matrix which traps water
  • These are used in medicine, eg; for wound dresses
  • This is because they provide moist and sterile conditions
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