23.1 - redox reactions

• Two ways redox reactions can be described in terms of


  Transfer of electrons or change in oxidation number.
• Transfer of electrons - reduction


  Gain of electrons
• Transfer of electrons - oxidation


  Loss of electrons
• Change in oxidation number - reduction


  Decrease in oxidation number.
• Change in oxidation number - oxidation


  Increase in oxidation number.
• Oxidation number of uncombined element


  0
• Oxidation number of combined hydrogen


  +1
• Oxidation number of combined oxygen


  -2
• Oxidation number of ion of an element


  Ionic charge
• What type of agents will there always be in a redox reaction?


  An oxidising agent and a reducing agent.
• Oxidising agent


  A reagent that takes electron from the species being oxidised, and contains the species that is reduced.
• Reducing agent


  A reagent that adds electrons to the species being reduced, and contains the species that is being oxidised.
• Wht products might we predict being in redox reactions?


  In aqueous redox reactions, H₂O is often formed. Other likely products are H⁺ and OH⁻ ions, depending on the conditions used.

  
  

  As a final check, ensure both sides of the equation are balanced by charge.