DP Chemistry (last assessment 2024)

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Question 18N.3.hl.TZ0.b

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Date November 2018 Marks available [Maximum mark: 2] Reference code 18N.3.hl.TZ0.b
Level hl Paper 3 Time zone TZ0
Command term Explain Question number b Adapted from N/A
b.
[Maximum mark: 2]
18N.3.hl.TZ0.b

The transport of oxygen around the body is essential for life.

Explain why carbon monoxide is very toxic and how it may be possible to treat carbon monoxide poisoning.

[2]

Markscheme

Toxicity:

carboxyhemoglobin/Hb–CO does not readily dissociate

OR

CO + Hb ⇌ Hb–CO AND forward reaction favoured

OR

affinity of carbon monoxide/CO for hemoglobin is «200 times/much» higher than that of oxygen/O2

OR

competitive inhibitor of oxygen/O2 binding ✔

 

Treatment:

moving patient to fresh air

OR

«in severe cases» inhaling pure oxygen/O2

OR

high pressure oxygen/O2 chamber ✔

 

Accept “move away from carbon monoxide/CO source” OR “remove carbon monoxide/CO source”.

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