Structure and reactions of alkenes

• Alkenes have the general formula CnH2n
• Ethene is an alkene with the formula C2H4
• Alkenes are described as unsaturated
• The first 4 alkenes are ethene, propene, butene and pentene
• alkenes have a double bond
• The functional group is usually the part of the molecule that reacts with other reactants
• Alkenes can react with hydrogen, water and halogens(for example, chlorine) which are called addition reactions
• In addition reactions, the double bond becomes a single bond which allows the 2 carbon atoms to make new bonds
• Alkenes are more likely to combust incompletely than alkenes are
• Like other hydrocarbons, alkenes combust (they can burn)
• Incomplete combustion happened when there’s not enough oxygen
• Alkenes tend to burn with a smoky flame
• Alkene + oxygen = carbon + carbon monoxide + water
• Compounds with a only a single C-C bond are called saturated compounds
• Crude oil is the substance found in the earth that we obtain ethene from
• Alkenes are made from alkanes by the process of cracking
• Hydrogen atoms add across the carbon double bond to form an alkane(ethane)