Structural Formula
Chemistry: Cambridge International GCSE Supplement, topic 11.1.6
Structural Formula
A structural formula clearly and simply shows the arrangement of atoms in a molecule. They became common after 1865, after Chemist August Kekulé proposed structures for benzene.
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What is a structural formula?
- A structural formula shows how atoms are linked in a molecule.
- It gives a clear picture of atom connections.
- It helps understand the shape and bonds in the molecule.
- Structural formula is more detailed than molecular formula.
Why use structural formula?
- Structural formula avoids confusion about atom arrangement.
- It gives an unambiguous description of molecules.
- Scientists use it to communicate exact structures.
- It helps predict chemical behaviour and reactions.
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Examples of structural formulae
- Ethene: CH2=CH2, showing a double bond between carbons.
- Ethanol: CH3CH2OH, showing an –OH group attached.
- Methyl ethanoate: CH3COOCH3, showing an ester group in the molecule.
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Reading structural formulae
- Letters show the type of atoms.
- For example, C for carbon, H for hydrogen.
- Lines between letters show bonds.
- Either single, double, or triple bonds
- Groups like CH3 or OH are called functional groups.
- Position of groups affects molecule properties.
Test yourself on Structural Formula
What is the primary information conveyed by a structural formula?
In a structural formula, what do the lines between letters typically represent?