DP Chemistry (last assessment 2024)

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Question 19M.3.sl.TZ2.b(ii)

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Date May 2019 Marks available [Maximum mark: 1] Reference code 19M.3.sl.TZ2.b(ii)
Level sl Paper 3 Time zone TZ2
Command term Determine Question number b(ii) Adapted from N/A
b(ii).
[Maximum mark: 1]
19M.3.sl.TZ2.b(ii)

A student synthesized aspirin, acetylsalicylic acid, in a school laboratory.

0.300 g of crude aspirin was dissolved in ethanol and titrated with sodium hydroxide solution, NaOH (aq).

NaOH (aq) + C9H8O4 (in ethanol) → NaC9H7O4 (aq) + H2O (l)

Determine the percentage purity of the synthesized aspirin.

[1]

Markscheme

«  0 .293 g 0.300  g × 100% » = 97.7 «%»  [✔]

Examiners report

This was a reasonably well answered question but quite a few students still struggled with what should have been a basic calculation, even when using ECF from the previous question.

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