Alkene Structures and Nomenclature Quiz

Alkenes Definition

• An alkene is a hydrocarbon containing a carbon–carbon double bond.

Characteristics

• The double bond can be internal or in the terminal position.
• Terminal alkenes are also known as α-olefins.

IUPAC Nomenclature

• The International Union of Pure and Applied Chemistry (IUPAC) recommends using the name "alkene" only for acyclic hydrocarbons with just one double bond.
• Alkadiene, alkatriene, etc., or polyene are used for acyclic hydrocarbons with two or more double bonds.
• Cycloalkene, cycloalkadiene, etc. are used for cyclic hydrocarbons.
• "Olefin" is used for the general class – cyclic or acyclic, with one or more double bonds.

Acyclic Alkenes

• Acyclic alkenes are hydrocarbons with only one double bond and no other functional groups.
• They form a homologous series with the general formula CnH2n, where n is 2 or more (two hydrogens less than the corresponding alkane).
• Isomers are possible when n is four or more, distinguished by the position and conformation of the double bond.

Physical Properties

• Alkenes are generally colorless and non-polar compounds.