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CAIE IGCSE Chemistry 3.1.3 Deduce the formula of a simple

CAIE IGCSE Chemistry 3.1.3 Deduce the formula of a simple
Cambridge IGCSE Chemistry 0620 syllabus for exams in 2026, 2027 and 20282026–2028

Practise deducing simple compound formulae by comparing atom numbers in models, diagrams or given chemical formulae.

How this is tested

  • use atom ratios in a model, diagram or formula to decide the correct compound formula

Question 9

[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