What this tests
Syllabus point 1.2 — Diffusion, in States of matter. Difficulty hard (estimated from the question's demands, not a Cambridge rating).
Also set in
The same question, as Cambridge printed it in other papers.
Cambridge IGCSE Chemistry 0620 · 1.2 Diffusion
November 2025 · Paper 21 · Question 2
One real Cambridge question from States of matter, with the official answer. Cambridge has printed this question 2 times.