Alkanes

• Saturated Hydrocarbons

  1. Contain only single carbon-carbon sigma-covalent bonds
  2. Only elements present are carbon and hydrogen.
• Shape

  Tetrahedral shape

  • 4 bonding pairs of electrons; forms four single sigma bonds
  • 109.5
• Alkanes have low reactivity


  Relatively strong sigma bonds present

  • High bond enthalpy
  • Non-polar; similar/same electronegativity between C and H
• Combustion

  Complete - Carbon Dioxide and Water

  Incomplete - Carbon Monoxide/Carbon and Water
• Free radical substitution

  1. Initiation
  2. Propagation
  3. Termination
  4. Further substitution
• Sigma bonds

  Overlap of orbitals directly between the bonding atoms.

  • Free rotation of the sigma bonds.
• Boiling point increases as chain length increases


  Increases amount of induced dipole-dipole interactions forming.
• Boiling point decreases as branching increases.


  Lowers amount of surface area available for induced dipole-dipole interactions.