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As we progress in our study of organic chemistry, it will become extremely important to
be able to quickly recognize the most common functional groups.

Reason-because they are the key structural elements that define how organic molecules
react.

For now, we will only worry about drawing and recognizing each functional group, as
depicted by Lewis and line structures.

 Alkanes [C-C]-

The 'default' in organic chemistry (essentially, the lack of any functional groups) is
given the term alkane, characterized by single bonds between carbon and carbon, or
between carbon and hydrogen.

Methane, CH 4, is the natural gas you may burn in your furnace. Octane, C 8H 18, is a
component of petrol.

 Alkenes [C=C] and alkynes [C≡C]-

Alkenes (sometimes called olefins) have carbon-carbon double bonds,
and alkynes have carbon-carbon triple bonds.

Ethene, the simplest alkene example, is a gas that serves as a cellular signal in
fruits to stimulate ripening. (If you want bananas to ripen quickly, put them in a
paper bag along with an apple - the apple emits ethene gas, setting off the
ripening process in the bananas).

Ethyne, commonly called acetylene, is used as a fuel in welding blow torches.

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