DP Chemistry (last assessment 2024)

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Question 22N.2.sl.TZ0.4a.i

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Date November 2022 Marks available [Maximum mark: 3] Reference code 22N.2.sl.TZ0.4a.i
Level sl Paper 2 Time zone TZ0
Command term Deduce Question number a.i Adapted from N/A
a.i.
[Maximum mark: 3]
22N.2.sl.TZ0.4a.i

An organic compound, A, reacts with ethanoic acid to produce B using concentrated sulfuric acid as a catalyst.

(a.i)

Deduce the structural and empirical formulas of B.

[3]

Markscheme

Structure:

ester functional group ✔

rest of structure ✔


Empirical Formula:

C3H5O ✔

 

Accept condensed/skeletal formula.

Examiners report

A question that discriminated well between high-scoring and low-scoring candidates. The average mark on this three-mark question was 1.3. The majority of candidates did not recognize it as an esterification reaction and the ester functional group was only seen in a small proportion of the scripts. Some candidates earned a mark for the remainder of the structure. Only about half of the candidates earned error carried forward for the mark allocated for the empirical formula. Some candidates had the molecular formula instead, and some candidates miscounted the numbers of atoms in the structure they drew.

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