Alkanes: properties & combustion

• What are alkanes classified as?

  A homologous series of hydrocarbons
• What elements do alkanes contain?

  Only carbon and hydrogen atoms
• What is the characteristic of alkanes regarding double bonds?

  They contain no double bonds
• How many alkanes were covered in the video?

  The first four alkanes
• What happens to the boiling point of alkanes as the carbon chain length increases?

  The boiling point increases with chain length
• What state do the first four alkanes exist in at room temperature?

  Gases
• What happens to longer alkanes at room temperature?

  They are liquids or solids
• What does it mean for shorter alkanes to be more volatile?

  They evaporate more easily
• How do longer alkanes compare in viscosity to shorter alkanes?

  Longer alkanes are more viscous
• What does it mean for shorter alkanes to be more flammable?

  They ignite or burn more easily
• What is produced during complete combustion of hydrocarbons?

  Carbon dioxide and water
• What is one main use of hydrocarbons like alkanes?

  They are used as fuel
• What type of reaction is combustion?

  An exothermic reaction
• What happens to hydrogen and carbon in hydrocarbons during combustion?

  They are oxidized
• What is the molecular formula of propane?

  C₃H₈
• How do you balance the combustion equation for propane?

  3 CO₂ and 4 H₂O
• How many oxygen molecules are needed to balance the combustion of propane?

  5 O₂ molecules
• What is the molecular formula of nonane?

  C₉H₂₀
• How do you balance the combustion equation for nonane?

  9 CO₂ and 10 H₂O
• How many oxygen molecules are needed to balance the combustion of nonane?

  14 O₂ molecules
• What are the properties of alkanes related to carbon chain length?

  • Boiling point increases with chain length
  • Shorter alkanes are gases at room temperature
  • Longer alkanes are liquids or solids
  • Shorter alkanes are more volatile
  • Longer alkanes are more viscous
  • Shorter alkanes are more flammable
• What is the process of combustion in hydrocarbons?

  • Hydrocarbon reacts with oxygen
  • Produces carbon dioxide and water
  • Releases energy (exothermic reaction)
  • Requires sufficient oxygen for complete combustion
• What is the key takeaway about hydrocarbons like alkanes?

  • Properties depend on carbon chain length
  • Shortest hydrocarbons are most volatile and flammable
  • Combustion produces energy, CO₂, and H₂O