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Introduction to Alkenes

Functional Groups in Organic Chemistry

Alkanes, which contain only carbon-carbon and carbon-hydrogen single bonds, usually react only under drastic conditions. Examples of such reactions are the pyrolysis or the radical substitution. Molecules with functional groups behave differently.

Definition "functional group"
Functional groups are small molecular subunits which are multiple bonds or heteroatoms like oxygen, nitrogen or a halogen. Many functional groups show polar bonds, which increase their reactivity.

Multiple bonds between carbon atoms are functional groups, because these bonds are richer in electrons and therefore much more reactive than carbon-carbon single bonds.

Tab.1
Molecules with functional groups
Fig.1
Fig.2
Fig.3
Fig.4
Fig.5
Ethanol Chloroethane Ethylamine Ethylene Acetylene

Knowing the specific reactions of a given functional group makes the prediction of the reactions of a molecule much easier. That way it is not necessary to learn thousands of reactions by heart.

Exercise

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