DP Chemistry (last assessment 2024)

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Question 22N.2.hl.TZ0.e.iv

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Date November 2022 Marks available [Maximum mark: 1] Reference code 22N.2.hl.TZ0.e.iv
Level hl Paper 2 Time zone TZ0
Command term Explain Question number e.iv Adapted from N/A
e.iv.
[Maximum mark: 1]
22N.2.hl.TZ0.e.iv

Chloroquine is a medication used to prevent and treat malaria.

Chloroquine can be synthesized by reacting 4,7-dichloroquinoline with another reactant, B.

            4,7-dichloroquinoline                                                            chloroquine

Explain, referring to the Maxwell–Boltzmann distribution curve, the effect of a catalyst on a chemical reaction.

[1]

Markscheme

increases rate AND there is a greater area under the curve past activation energy

OR

increases rate AND greater proportion of/more molecules have «kinetic» EEa «(cat) than Ea (uncat)» ✔

 

Do not award a mark for general statements about catalysts such as “provides alternative pathway” or “lowers Ea”.

Examiners report

Most knew about catalysts providing an alternative mechanism, but some failed to gain the mark by not referring back to the diagram, whilst others lost it through not stating catalysts cause the reaction rate to increase.