4.1.2 alkanes

• Alkanes - saturated hydrocarbon containing a single carbon carbon bonds and carbon hydrogen bonds as sigma bonds that freely rotate
• Sigma bonding - overlap of orbitals directly between the bonding atoms
• Has carbon chain length increases the boiling points increase because more London forces increase so more energy is required to overcome them
• Incomplete combustion occurs when there is a limited oxygen
• Alkane + halogen --> haloalkane + hydrogen halide
• First step of free radical substitution

  The halogen undergoes homolytic fission using UV light to form two halogen radicals
• Three steps in the mechanism of free radical substitution

  Initiation, propagation, and termination
• Two limitations of free radical substitution

  Further substitutions can occur

  Substitutions occur at different positions along the carbon chain
• The substitution reactions of alkanes the mechanism for this reaction is called a free radical substitution