What is the structure of alkenes and how do they differ from alkanes?

Alkenes have a double bond between two carbon atoms, while alkanes have only single bonds.

Alkenes are hydrocarbons that contain at least one carbon-carbon double bond. This double bond consists of one sigma bond and one pi bond, which is formed by the overlap of two p orbitals. The general formula for alkenes is CnH2n, where n is the number of carbon atoms in the molecule. The double bond in alkenes is responsible for their reactivity and ability to undergo addition reactions.

Alkenes differ from alkanes in their physical and chemical properties. Due to the presence of the double bond, alkenes have a lower boiling point and are less dense than alkanes of similar molecular weight. They are also more reactive than alkanes and can undergo addition reactions with electrophiles such as hydrogen halides and water.

The double bond in alkenes can also undergo isomerization, where the position of the double bond is shifted within the molecule. This results in the formation of different isomers with different physical and chemical properties. Alkenes can also be used as starting materials for the synthesis of a variety of organic compounds, including alcohols, aldehydes, and carboxylic acids.

In summary, alkenes are hydrocarbons with a double bond between two carbon atoms. They differ from alkanes in their physical and chemical properties, reactivity, and ability to undergo isomerization and addition reactions.