DP Chemistry (first assessment 2025)

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Question 20N.1B.SL.TZ0.d

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Date November 2020 Marks available [Maximum mark: 1] Reference code 20N.1B.SL.TZ0.d
Level SL Paper 1B Time zone TZ0
Command term Outline Question number d Adapted from N/A
d.
[Maximum mark: 1]
20N.1B.SL.TZ0.d

An additional experiment was conducted in which only the sulfuric acid catalyst was titrated with NaOH (aq). Outline why this experiment was necessary.

[1]

Markscheme

to determine volume/moles of NaOH used up by the catalyst/sulfuric acid «in the titration»
OR
to eliminate/reduce «systematic» error caused by acid catalyst ✔


Do not accept “control” OR “standard” alone.

Examiners report

Some students achieved on mark. Many answers referred simple to "control" or "standard" underlining the lack of some skills as also identified in the Internal assessment. Once again very few students had the specific details necessary to explain why this separate titration was needed in their response to receive a mark.

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