DP Chemistry (first assessment 2025)

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Question 21M.1A.SL.TZ1.23

Date	May 2021	Marks available	[Maximum mark: 1]	Reference code	21M.1A.SL.TZ1.23
Level	SL	Paper	1A	Time zone	TZ1
Command term	Solve	Question number	23	Adapted from	N/A

23.

[Maximum mark: 1]

21M.1A.SL.TZ1.23

1.0 mol each of sulfur dioxide, oxygen, and sulfur trioxide are in equilibrium.

$2 {SO}_{2} (g) + O_{2} (g) ⇌ 2 {SO}_{3} (g)$

Which change in the molar ratio of reactants will cause the greatest increase in the amount of sulfur trioxide?

Assume volume and temperature of the reaction mixture remain constant.

[1]

Markscheme

D

Syllabus sections

Structure 1. Models of the particulate nature of matter » Structure 1.4—Counting particles by mass: The mole » Structure 1.4.6—Avogadro’s law states that equal volumes of all gases measured under the same conditions of temperature and pressure contain equal numbers of molecules. Solve problems involving the mole ratio of reactants and/or products and the volume of gases.