An alkene is a type of hydrocarbon that contains at least one carbon-carbon double bond. This double bond gives alkenes unique properties, making them more reactive than alkanes, which only have single bonds. Alkenes are commonly found in various natural and synthetic substances, including fuels and plastics. The simplest alkene is ethylene, which is used in the production of many everyday products. Alkenes can undergo various chemical reactions, such as addition reactions, where other atoms or groups can attach to the carbon atoms involved in the double bond. This reactivity is important in organic chemistry and is utilized in the creation of complex molecules. Understanding alkenes is essential for fields like chemical engineering and biochemistry.