DP Chemistry (first assessment 2025)

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Question 21M.2.HL.TZ1.b(ii)

Date	May 2021	Marks available	[Maximum mark: 1]	Reference code	21M.2.HL.TZ1.b(ii)
Level	HL	Paper	2	Time zone	TZ1
Command term	Deduce	Question number	b(ii)	Adapted from	N/A

b(ii).

[Maximum mark: 1]

21M.2.HL.TZ1.b(ii)

Deduce the relationship between the concentration of N₂O₅ and the rate of reaction.

[1]

Markscheme

« rate of reaction is directly» proportional to/∝[N₂O₅]
OR
doubling concentration doubles rate ✔

Do not accept “rate increases as concentration increases”/ positive correlation

Accept linear

Syllabus sections

Reactivity 2. How much, how fast and how far? » Reactivity 2.2—How fast? The rate of chemical change » Reactivity 2.2.10—The order of a reaction with respect to a reactant is the exponent to which the concentration of the reactant is raised in the rate equation. The order with respect to a reactant can describe the number of particles taking part in the rate determining step. The overall reaction order is the sum of the orders with respect to each reactant. Sketch, identify and analyse graphical representations of zero, first and second order reactions.