Alkenes

Definition

Alkenes are hydrocarbons that contain at least one carbon-carbon double bond (C=C). They are unsaturated compounds with the general formula $C_nH_{2n}$.

5 Must Know Facts For Your Next Test

1. Alkenes undergo addition reactions, where the double bond opens up to add new atoms or groups.
2. The simplest alkene is ethene (ethylene), with the chemical formula $C_2H_4$.
3. In alkenes, the carbon atoms involved in the double bond are sp2 hybridized and have a trigonal planar geometry.
4. Common reactions involving alkenes include hydrogenation, halogenation, and hydrohalogenation.
5. The presence of a double bond makes alkenes more reactive than alkanes.

Review Questions

• What is the general formula for alkenes?
• Describe the type of hybridization and geometry found in an alkene's double-bonded carbons.
• Name three common types of reactions that involve alkenes.

Related terms

Hydrogenation:

A chemical reaction where hydrogen is added to an alkene, converting it into an alkane.

Halogenation:

A reaction where a halogen (such as chlorine or bromine) is added to an alkene, resulting in a dihalide.

Unsaturated Hydrocarbons: Hydrocarbons that contain double or triple bonds between carbon atoms, such as alkenes and alkynes.