alkanes properties and combustion

• What are alkanes classified as in terms of their chemical structure?


  Alkanes are a homologous series of hydrocarbons.
• What elements do alkanes contain?


  Alkanes contain only carbon and hydrogen atoms.
• What is a key characteristic of alkanes regarding double bonds?


  Alkanes have no double bonds.
• 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 the length of the carbon chain?


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


  The first four alkanes exist as gases at room temperature.
• What happens to longer alkanes with more than four carbons at room temperature?


  They are liquids or can be solids if the chains are very long.
• What does it mean for shorter alkanes to be more volatile?


  Shorter alkanes evaporate more easily due to their low boiling points.
• How do longer alkanes compare to shorter alkanes in terms of viscosity?


  Longer alkanes are more viscous, meaning they are thicker and stickier.
• Why are shorter alkanes considered more flammable?


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


  • Used as fuel
  • Release energy when burned with oxygen
• What is complete combustion of hydrocarbons?


  Complete combustion occurs when a hydrocarbon reacts with oxygen to form carbon dioxide and water.
• What type of reaction is combustion in terms of energy?

  Combustion is an exothermic reaction.
• What happens to hydrogen and carbon in hydrocarbons during combustion?


  They are oxidized by combining with oxygen to form carbon dioxide and water
• What is required for complete combustion to occur?


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


  The products are carbon dioxide and water.