alkanes: properties & combustion

• What are alkanes classified as in chemistry?

  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 their bonds?

  Alkanes have no double bonds.
• How many alkanes were covered in the video?

  The first four alkanes in the series were covered.
• What happens to the boiling point of alkanes as the carbon chain length increases?

  The boiling point increases with chain length.
• Why do shorter alkanes exist as gases at room temperature?

  Because they have fairly low boiling points.
• What state are longer alkanes with more than four carbons at room temperature?

  They are liquids at room temperature.
• What is the property of shorter alkanes regarding volatility?

  Shorter alkanes are more volatile and evaporate more easily.
• How do longer alkanes compare to shorter alkanes in terms of viscosity?

  Longer alkanes are more viscous, meaning they are thick and sticky.
• What does it mean for shorter alkanes to be more flammable?

  It means they are easier to ignite or burn.
• What is one of the main uses of hydrocarbons like alkanes?

  They are used as fuel because they release energy when burned.
• What is complete combustion of a hydrocarbon?

  It is 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 CO2 and H2O.
• What is the balanced equation for the complete combustion of propane (C3H8)?

  C3H8 + 5 O2 → 3 CO2 + 4 H2O
• How do you balance the combustion equation for propane?

  Balance carbons, then hydrogens, and finally oxygens.
• What is the unbalanced equation for the combustion of nonane (C9H20)?

  C9H20 + O2 → CO2 + H2O
• How many CO2 molecules are produced from the combustion of nonane?

  9 CO2 molecules are produced.
• How many H2O molecules are produced from the combustion of nonane?

  10 H2O molecules are produced.
• How do you balance the oxygen in the combustion of nonane?

  You need 14 O2 molecules to balance the oxygen atoms.
• What are the key properties of alkanes based on carbon chain length?

  • Shorter alkanes have lower boiling points, are more volatile, and are more flammable.
  • Longer alkanes have higher boiling points, are less volatile, and are more viscous.
• What is the process of combustion in hydrocarbons?

  • Combustion occurs when hydrocarbons react with oxygen.
  • It produces carbon dioxide and water.
  • It releases energy and is an exothermic reaction.
• What is the general outcome of complete combustion of hydrocarbons?

  • Produces carbon dioxide (CO2)
  • Produces water (H2O)
  • Releases energy
• What is the significance of the carbon chain length in hydrocarbons?

  • Determines boiling point
  • Affects volatility and flammability
  • Influences viscosity