ConceptConceptDocsDocuments

CAIE IGCSE Chemistry 3.1.2 Molecular formula of a compound as the

Practise reading molecular formulae from structures and formula lists by counting each type of atom in one molecule.

Syllabus
2026–2028
Course
Chemistry 0620

Exam points

  • count atoms in a displayed molecule to select the correct molecular formula
  • distinguish molecular formulae from grouped or simplified formula options

3.1.2—Molecular formula of a compound as the question 1

[Maximum number: 1]

The chemical formulae of two substances, W and X, are given.
W NaAlSi3O8\mathrm{NaAlSi}_{3} \mathrm{O}_{8}
X CaAl2Si2O8\quad \mathrm{CaAl}_{2} \mathrm{Si}_{2} \mathrm{O}_{8}
Which statements are correct?

1 W and X contain the same amount of oxygen.
2 W contains three times as much silicon as X.
3 X contains twice as much aluminium as W.
A1 and 2
B1 and 3
C 2 and 3
D 1, 2 and 3

All question bank results loaded