Alkenes are hydrocarbons are formed only of Carbon and Hydrogen. They are contain a double carbon (C=C)  and are often known as unsaturated molecules (for information on saturated molecules visit the alkanes page)

Synthesis

Alkenes can be synthesised using two methods

• Cracking of alkanes
• Dehydration of alcohols

Reactions

Alkenes undergo many different reactions.

• Addition
  • Hydrogenation
    Addition of hydrogen across the double bond
  • Halogenation
    Addition of halogens across the double bond
  • Hydration
    Addition of water across the double bond
• Polymerisation
  • Opening of the double bond to form a large molecule known as a polymer.

Addition

Hydrogenation

Halogenation

Hydration