What this tests
Syllabus point 3.2 — Relative masses of atoms and molecules, in Stoichiometry. Difficulty easy (estimated from the question's demands, not a Cambridge rating).
Cambridge IGCSE Chemistry 0620 · 3.2 Relative masses of atoms and molecules
March 2021 · Paper 22 · Question 10
One real Cambridge question from Stoichiometry, with the official answer.