DP Chemistry (last assessment 2024)

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

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Date November 2020 Marks available [Maximum mark: 3] Reference code 20N.3.hl.TZ0.3b(ii)
Level hl Paper 3 Time zone TZ0
Command term Explain Question number b(ii) Adapted from N/A
b(ii).
[Maximum mark: 3]
20N.3.hl.TZ0.3b(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.

 

(b(ii))

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

This also was well done and some managed to score all three marks.

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