Alkenes - Properties and Combustion

• The first 4 alkanes are methane, ethane, propane and butane.

  
• Methane, ethane, propane and butane are in the homologous series so they all react in the same way with similar properties.
• The general formula is CₙHₙ₂₊₂ to work out the number of atoms in an alkane.
• Alkanes are saturated compounds.
• In an alkane every carbon atom has four single covalent bonds. 
• In alkanes if a double bond is created, each of the carbons involved lose a hydrogen atom. 
• Alkanes don't contain double bonds. This would make it an alkene.
• Isomers are molecules that have the same molecular formula, but different structural formulas, this means they are made of the same atoms, but the atoms are arranged differently.

  
• In alkanes the boiling point increases as hydrocarbons become longer.
• Shorter alkanes evaporate more easily (volatile).
• Longer alkanes are viscous (thick like honey).
• Shorter alkanes are more flammable.
• Combustion reactions, such as when we use hydrocarbons as fuels.
• Complete combustion = Hydrocarbon + Oxygen → Carbon Dioxide + Water
• Complete combustion is an exothermic reaction.
• Hydrogen and carbon become oxidised in complete combustion.
• What are the products of complete combustion?

  Carbon dioxide and water