DP Chemistry (last assessment 2024)

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Question 20N.3.sl.TZ0.b(ii)

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Date November 2020 Marks available [Maximum mark: 3] Reference code 20N.3.sl.TZ0.b(ii)
Level sl Paper 3 Time zone TZ0
Command term Explain Question number b(ii) Adapted from N/A
b(ii).
[Maximum mark: 3]
20N.3.sl.TZ0.b(ii)
Carbon fibre reinforced plastic (CFRP) is a useful composite. Epoxy is a thermoset polymer that is used as a binding polymer when making CFRP.

 

Explain how thermoplastics, such as polyvinylchloride, PVC, can be made more flexible by the addition of phthalate ester plasticizers.

[3]

Markscheme

Any three of:

plasticizers embed/fit between «polymer» chains ✔

keep polymer strands/chains/molecules separated/apart ✔

weaken intermolecular/London/dispersion/attractive/forces/instantaneous induced dipole-induced dipole/forces «between chains» ✔

prevent chains from packing closely/forming regular packing/structure ✔


Accept “van der Waals/vdW” for “London”.

Examiners report

Approximately 1% of the candidates this session attempted this option so feedback on this section by question is not possible due to the minimal number of scripts available for marking. The students that did attempt this option did not perform very well with several of them leaving some questions unanswered.

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