CIE AS Chemistry (9701) exams from 2022

Revision Notes

3.1.2 Functional Groups and their Formulae

Functional Groups of Organic Compounds

  • Functional groups determine the physical and chemical properties of molecules
  • The table below shows a summary of common functional groups found in compounds
  • R is any other atom or group of atoms (except for hydrogen)

Functional groups found in compounds table

An Introduction to AS Level Organic Chemistry Functional Groups, downloadable AS & A Level Chemistry revision notes

Formulae of Organic Compounds

  • The general formula is a formula that represents a homologous series of compounds using letters and numbers
    • Eg. the general formula of alkanes is CnH2n+2
    • A homologous series is a group of organic compounds that have the same functional group, the same general formula and the same chemical properties
  • The structural formula is a formula that shows how the atoms are bonded to each carbon atom in a molecule
  • The displayed formula is a 2D representation of an organic molecule showing all its atoms (by their symbols) and their bonds (by single, double or triple bonds)
  • The skeletal formula is a simplified displayed formula with all the carbon and hydrogen (C-H) bonds removed

Overview of the formulae of organic compounds table

An Introduction to AS Level Organic Chemistry Formulae of Organic Compounds, downloadable AS & A Level Chemistry revision notes

Worked example: Drawing skeletal formulae of molecules

An Introduction to AS Level Organic Chemistry Worked example - Drawing skeletal formulae of molecules, downloadable AS & A Level Chemistry revision notes

An Introduction to AS Level Organic Chemistry Answer Worked example - Drawing skeletal formulae of molecules, downloadable AS & A Level Chemistry revision notes

Worked example: Drawing displayed formulae of molecules

An Introduction to AS Level Organic Chemistry Worked example - Drawing displayed formulae of molecules, downloadable AS & A Level Chemistry revision notes

An Introduction to AS Level Organic Chemistry Answer Worked example - Drawing displayed formulae of molecules, downloadable AS & A Level Chemistry revision notes

Author: Francesca

Fran has taught A level Chemistry in the UK for over 10 years. As head of science, she used her passion for education to drive improvement for staff and students, supporting them to achieve their full potential. Fran has also co-written science textbooks and worked as an examiner for UK exam boards.
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