DP Chemistry (last assessment 2024)

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Question 19M.3.hl.TZ1.c

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Date May 2019 Marks available [Maximum mark: 2] Reference code 19M.3.hl.TZ1.c
Level hl Paper 3 Time zone TZ1
Command term Outline Question number c Adapted from N/A
c.
[Maximum mark: 2]
19M.3.hl.TZ1.c

Polybutadiene, used in truck tyres, is a polymer of buta-1,3-diene. The spatial arrangement of atoms in the polymer depends on the type of catalyst used.

Tyre fires emit trace quantities of polychlorinated dibenzofurans and polychlorinated dibenzo-p-dioxin.

Outline, using section 31 of the data booklet, why polychlorinated dibenzofuran is not classed chemically as a dioxin but considered “dioxin-like”.

[2]

Markscheme

does not contain heterocyclic ring with 2 oxygen atoms
OR
middle ring has only 1 oxygen atom    [✔]

produces similar toxic effects to dioxins    [✔]

Examiners report

But had difficulty applying their knowledge to outline why polychlorinated dibenzofuran is considered dioxin-like but is not classified as a dioxin.

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