DP Chemistry (last assessment 2024)

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Question 20N.3.sl.TZ0.6a

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Date November 2020 Marks available [Maximum mark: 2] Reference code 20N.3.sl.TZ0.6a
Level sl Paper 3 Time zone TZ0
Command term Deduce Question number a Adapted from N/A
a.
[Maximum mark: 2]
20N.3.sl.TZ0.6a
Phospholipids are a main component of cell membranes.

 

(a)

Deduce the products of the hydrolysis of a non-substituted phospholipid, where R1 and R2 represent long alkyl chains.

[2]

Markscheme

glycerol ✔

both fatty acids AND phosphoric acid ✔

Accept either names OR structures.
Accept “long chain carboxylic acid” for “fatty acid”.

Penalize once only if an incorrect name is given for a correct structure or vice-versa.

Examiners report

Not as well answered as expected. However, many candidates managed to score at least one point. Quite a few lost the only mark due to wrong linkage. Some students drew fatty acid structures with aldehydes or phosphoric acid with incorrect bond linkages in the structure (OH-).