Alkanes

• What are alkanes classified as in chemistry?

  A homologous series of hydrocarbons
• What elements do alkanes contain?

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

  They contain no double bonds
• What are the names of the first four alkanes in the series?

  Methane, ethane, propane, butane
• What are the trends in the properties of alkanes as the carbon chain length increases?

  • Boiling point increases with chain length
  • Shorter alkanes are gases at room temperature
  • Longer alkanes are liquids or solids at room temperature
• Why do shorter alkanes have lower boiling points?

  Because they have shorter carbon chains
• What does it mean for an alkane to be more volatile?

  It evaporates more easily
• How does the viscosity of alkanes change with chain length?

  Longer alkanes are more viscous
• What does it mean for an alkane to be more flammable?

  It is easier to ignite or burn
• 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 a hydrocarbon?

  When it reacts with oxygen to form carbon dioxide and water
• What type of reaction is combustion?

  An exothermic reaction
• What happens to hydrogen and carbon in hydrocarbons during combustion?

  They are oxidized by combining with oxygen
• What is the balanced equation for the complete combustion of propane (\(C_3H_8\))?


  \(C_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O\)
• How do you balance the combustion equation for propane?

  By ensuring the number of carbons, hydrogens, and oxygens are equal on both sides
• What is the unbalanced equation for the combustion of nonane (\(C_9H_{20}\))?

  \(C_9H_{20} + O_2 \rightarrow CO_2 + H_2O\)
• What is the balanced equation for the combustion of nonane (\(C_9H_{20}\))?

  \(C_9H_{20} + 14O_2 \rightarrow 9CO_2 + 10H_2O\)
• What is required for complete combustion to occur?

  Enough oxygen must be available
• What are the key points about the properties of hydrocarbons like alkanes?

  • Properties depend on the length of the carbon chain
  • Shortest hydrocarbons have the lowest boiling points
  • Shorter alkanes are more volatile and flammable
  • Combustion of hydrocarbons produces carbon dioxide and water
• What is the energy outcome of combustion reactions of hydrocarbons?

  They release loads of energy
• What are the products of complete combustion of hydrocarbons?

  Carbon dioxide and water