Possible Key Topics For 2012 Chemistry C7 Pre-release

Has 5 bits on things that might show up on this year question 1

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Preview of Possible Key Topics For 2012 Chemistry C7 Pre-release

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Chemistry Pre-Release Martha Brown 18/05/2012
Mrs Mallalieu
1) A plasticizer is a molecule that is attached on long polymer chains. The plasticizer makes the
chains less rigid, allowing for plastics that are soft and flexible, like carrier bags for example.
2) A polymer material is a material that is made up of lots of very long strings of molecules. The
longer the chains the more energy it takes to break them.
4) The materials u-PVC and PVC are both similar and different. u-PVC is a lot harder has more
strength. The particles inside u-PVC do not move around freely and the chains have a lot of
force between them. In PVC the particles have weaker forces between them. In these,
plasticisers have been added. This means the chains can slide over each other more easily
than they can in u-PVC. The long polymer chains are further apart in PVC than they are in
u-PVC weakening the forces. They do have some similarities though, for example both PVC
and u-PVC are made up of long polymer chains. Both materials exhibit similar properties in
the material as both are just different forms of plastics.
5) Plasticizers are small oily molecules that sit in between chains of polymers in PVC. This
reduces the forces holding the chains together and also enables the chains to be able to slide
over each other more easily.

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