FREE RADICAL REACTION

• HETEROLYTIC FISSION?

  after a covalent bond breaks, both electrons from a shared pair go to one atom
• WHAT DOES HETEROLYTIC FISSION FORM?

  ions
• WHAT IS HETEROLYTIC FISSION THE RESULT OF?

  electronegativity difference
• RADICAL?

  species with an unpaired electron
• FREE RADICAL?

  a highly reactive/ unstable radical
• HOMOLYTIC FISSION?

  after a covalent bond breaks, the shared pair of electrons are split equally between atoms
• WHAT DOES HOMOLYTIC FISSION FORM?

  free radicals
• WHAT IS HOMOLYTIC FISSION A RESULT OF?

  similar electronegativity
• WHAT ARE THE THREE STAGES OF RADICAL REACTION?

  1. Initiation
  2. Propagation
  3. Termination
• INITIATION EQUATION?

  molecule -> radical + radical
• PROPAGATION EQUATION?

  radical + molecule -> radical + molecule
• TERMINATION EQUATION?

  radical + radical -> molecule
• INITIATION?

  radicals form when a covalent bond is broken by homolytic fission
• WHAT ARE HALOGENS SPLIT WITH?

  UV radiation
• PROPAGATION?

  radical reacts with another reactant molecule to form a new radical and new molecule (starts a chain reaction)
• TERMINATION?

  2 radicals combine to form a molecule (stable)
• WHAT HAPPENS IN A FREE RADICAL SUBSTITUTION REACTION?

  hydrogen atom replaced by halogen atom
• FORMULA FOR OZONE?

  O3
• WHAT DOES OZONE DO?

  absorbs UV radiation
• CFCs?

  chlorofluorocarbons
• WHAT ARE CFCs USED IN?

  • fridges (coolants)
  • aerosols (propellants)
  • dry cleaning solvents
  • degreasing circuit boards
• HOW DO CFCs REACH THE OZONE?

  • rise to stratosphere
  • UV provides energy to break C-Cl bonds
  • forms Cl. radicals
  • react to destroy O3 in chain reaction