Hydrocarbons

• What is the definition of hydrocarbons?


  Hydrocarbons are compounds formed from carbon and hydrogen atoms only.
• Why are hydrocarbons considered the simplest organic compounds?

  Because they consist only of carbon and hydrogen atoms.
• What is an example of a hydrocarbon?


  Decane (C₁₀H₂₂) is an example of a hydrocarbon.
• What type of bonds do alkanes have?


  Alkanes have all C–C single bonds.
• What is the general formula for alkanes?


  The general formula for alkanes is CₙH₂ₙ₊₂.
• What is a homologous series?


  A homologous series is a group of organic compounds that react in a similar way.
• What are the first four alkanes?


  The first four alkanes are methane, ethane, propane, and butane.
• What is the molecular formula for methane?


  The molecular formula for methane is CH₄.
• What is the molecular formula for ethane?


  The molecular formula for ethane is C₂H₆.
• What is the molecular formula for propane?


  The molecular formula for propane is C₃H₈.
• What is the molecular formula for butane?


  The molecular formula for butane is C₄H₁₀.
• How do the properties of hydrocarbons change as the carbon chain gets longer?


  • The properties of hydrocarbons change with the length of the carbon chain.
  • Shorter chains are less viscous (more runny).
  • Shorter chains are more volatile (lower boiling points).
  • Shorter chains are more flammable (easier to ignite).
• What is the relationship between carbon chain length and viscosity in hydrocarbons?


  Shorter carbon chains result in less viscous (more runny) hydrocarbons.
• How does carbon chain length affect the volatility of hydrocarbons?


  Shorter carbon chains have lower boiling points and are more volatile.
• How does carbon chain length influence the flammability of hydrocarbons?


  Shorter carbon chains are more flammable and easier to ignite.
• How are hydrocarbons used as fuels?


  • Properties of hydrocarbons affect their use as fuels.
  • Short chain hydrocarbons with lower boiling points are used as 'bottled gases.'
  • They are stored under pressure as liquids in bottles.
• What occurs during complete combustion of hydrocarbons?


  Complete combustion releases energy, producing carbon dioxide and water vapour.
• What are the waste products of complete combustion of hydrocarbons?


  The waste products are carbon dioxide and water vapour.
• What happens to carbon and hydrogen during combustion of hydrocarbons?


  Both carbon and hydrogen are oxidised during combustion.
• What is the general equation for the complete combustion of a hydrocarbon?


  • Hydrocarbon + Oxygen → Carbon Dioxide + Water (+ Energy)
• How do you write a balanced symbol equation for the complete combustion of a hydrocarbon?


  • Identify the molecular formula of the hydrocarbon.
  • Balance the equation using the number of carbon and hydrogen atoms.
  • Include oxygen to balance the products.
• What is the significance of hydrocarbons in energy release?


  • Hydrocarbons are used as fuels due to the energy released during complete combustion.