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Chapter 12 - Alkanes - Coggle Diagram

- - - - Reaction is started when covalent bond in a bromine molecule is broken by homolytic fission
      - Each bromine atom takes one electron from the pair
      - Two highly reactive bromine radicals are formed
    - - Two propagation steps
      - 1 - a bromine radical reacts with a C-H bond in methane to form a methyl radical and a molecule of HBr
      - 2 - Each methyl radical reacts with another bromine molecule, to form CH3Br with a new bromine radical
      - New bromine radical reacts with another CH4 molecule, and the two steps continue to cycle
    - - Two radicals collide, forming a molecule with all electrons pair
      - When two radicals collide, both are removed and the reaction stops
- - - - As chain length increases, molecules have a larger surface area, so more surface contact is possible between molecules
      - Greater london forces between molecules, so more energy is required to overcome the forces
    - - There are fewer surface points of contact between molecules of the branced alkanes, meaning fewer london forces
      - More brances get in the way and prevent branched molecules getting as close together as a straight chain