A LevelChemistryCambridge (CIE)Revision Notes13. An Introduction to AS Level Organic ChemistryFormulas, Functional Groups & the Naming of Organic CompoundsMolecular & Empirical Formulae

Molecular & Empirical Formulae (Cambridge (CIE) A Level Chemistry): Revision Note

Exam code: 9701

Written by: Philippa Platt

Reviewed by: Caroline Carroll

Updated on 2 July 2026

Molecular & Empirical Formulae of Organic Compounds

The molecular formula shows the number and type of each atom in a molecule
- E.g. the molecular formula of ethanoic acid is C₂H₄O₂
The empirical formula shows the simplest whole number ratio of the elements present in one molecule of the compound
- E.g. the empirical formula of ethanol is CH₂O

Worked Example

Deduce the molecular and empirical formula of the following compounds:

Answers:

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Author: Philippa Platt

Expertise: Chemistry Content Creator

Philippa has worked as a GCSE and A level chemistry teacher and tutor for over thirteen years. She studied chemistry and sport science at Loughborough University graduating in 2007 having also completed her PGCE in science. Throughout her time as a teacher she was incharge of a boarding house for five years and coached many teams in a variety of sports. When not producing resources with the chemistry team, Philippa enjoys being active outside with her young family and is a very keen gardener

Reviewer: Caroline Carroll

Expertise: Head of Content Delivery

Caroline graduated from the University of Nottingham with a degree in Chemistry and Molecular Physics. She spent several years working as an Industrial Chemist in the automotive industry before retraining to teach. Caroline has over 12 years of experience teaching GCSE and A-level chemistry and physics. She is passionate about delivering high-quality resources to help students achieve their full potential.