Alkanes

• What are alkanes classified as?

  A homologous series of hydrocarbons
• What do alkanes contain?

  Only carbon and hydrogen atoms with no double bonds
• What are the names of the first four alkanes in the series?

  1. Methane (C$_1$H$_4$)
  2. Ethane (C$_2$H$_6$)
  3. Propane (C$_3$H$_8$)
  4. Butane (C$_4$H$_{10}$)
• What are the properties of alkanes related to their carbon chain length?

  • Boiling point increases with chain length
  • Shorter alkanes are gases at room temperature
  • Longer alkanes are liquids or solids at room temperature
• How does the boiling point of alkanes change with chain length?

  The boiling point increases as the chain length increases
• Why do shorter alkanes evaporate more easily?

  Because they have lower boiling points
• What does it mean for longer alkanes to be more viscous?

  They are thicker and stickier, like honey
• How does flammability change with alkane chain length?

  Shorter alkanes are more flammable
• What is the main use of hydrocarbons like alkanes?

  • They are used as fuels
  • They release energy when burned with oxygen
• What is complete combustion of hydrocarbons?

  It is when a hydrocarbon reacts with oxygen to form carbon dioxide and water
• What type of reaction is combustion?

  It is an exothermic reaction
• What happens to hydrogen and carbon during combustion?

  They are oxidized by combining with oxygen
• What is the balanced equation for the complete combustion of propane (C$_3$H$_8$)?


  C$_3$H$_8$ + 5 O$_2$ → 3 CO$_2$ + 4 H$_2$O
• How do you balance the combustion equation for nonane (C$_9$H$_{20}$)?


  C$_9$H$_{20}$ + 14 O$_2$ → 9 CO$_2$ + 10 H$_2$O
• What is the key point about the properties of hydrocarbons like alkanes?

  • Properties depend on the length of the carbon chain
  • Shortest hydrocarbons have the lowest boiling points
  • Short hydrocarbons are the most volatile and flammable
  • Combustion occurs when hydrocarbons are used as fuels
• What is required for complete combustion to occur?

  There must be enough oxygen available
• What are the products of complete combustion of hydrocarbons?

  Carbon dioxide and water
• What is released during the combustion of hydrocarbons?

  Loads of energy