1.7 Redox

• what is oxidation?


  loss of electrons
• what is reduction?


  gain of electrons
• what are reducing agents?

  lose electrons and are oxidised themselves
• what are oxidising agents?


  Gain electrons and are reduced themselves
• how can you tell something has been reduced?

  decrease in oxidation number
• how can you tell something has been oxidised?

  increase in oxidation number
• what are the rules for balancing half equations?


  1. write down the species before and after a reaction

  2. balance any atoms apart from oxygen and hydrogens

  3. balance any oxygens with H2O

  4. balance any hydrogens with H+ ions

  5. balance charges with electrons
• how do you combine half equations to make a full ionic equation?

  1. balance electrons as there should be none in the final ionic equation

  2. cancel out anything that appears on either side of the equation