combustion of hydrocarbons

• What are alkanes classified as?

  A homologous series of hydrocarbons
• What do alkanes contain?

  Only carbon and hydrogen atoms
• What is a key characteristic of alkanes?

  They have no double bonds
• 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
• Why are shorter alkanes more volatile?

  They have lower boiling points
• How do longer alkanes compare in viscosity to shorter alkanes?

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

  It is easier to ignite or burn
• What is the main use of hydrocarbons like alkanes?

  As fuel for energy release
• What is complete combustion?

  A hydrocarbon reacts with oxygen to form CO2 and H2O
• What type of reaction is combustion?

  Exothermic reaction
• What happens to hydrogen and carbon during combustion?

  They are oxidized by combining with oxygen
• What is the molecular formula for nonane?

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

  9 CO2 and 10 H2O on the right
• What are the properties of alkanes related to carbon chain length?

  • Boiling point increases with chain length
  • 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
• How do the properties of hydrocarbons like alkanes affect their use as fuels?

  • Shorter alkanes: low boiling points, more volatile, easier to ignite
  • Longer alkanes: higher boiling points, less volatile, harder to ignite
  • Ideal for energy release when burned
• what does viscous mean

  how easily something flows
• if a substance is very viscous that means its a bad fuel
• as the chain length (number of carbon atoms) of alkanes what happens to their viscousity


  they become more viscous
• what does volatile mean

  how easily somethings evaporates
• if a substance is very volatile it is a good fuel
• as the chain length (number of carbon atoms) of alkanes increases what happens to how volatile it is

  becomes less volatile
• what does flammable mean

  how easily something burns
• if a substance is easily flammable it is a good fuel
• as the chain length (number of carbon atoms) of alkanes increases what happens to how flammable it is

  it becomes less flammable
• During a combustion reaction, are carbon and hydrogen oxidised or reduced?

  oxidised