Oxidation & Reduction (OCR GCSE Chemistry A (Gateway)): Revision Note

Oxidation & Reduction

• Oxidation and reduction involve the addition or removal of oxygen from a substance

• Oxidation is a reaction in which:

  • Oxygen is added to an element or a compound

• Reduction is a reaction in which:

  • Oxygen is removed from an element or a compound

• A redox reaction is one where oxidation and reduction are both taking place at the same time

• In the following reaction:

ZnO + C ⟶ Zn + CO 

• The carbon atom has been oxidised since it has gained oxygen

  • The zinc oxide has been reduced since it has lost oxygen

  • This is an example of a redox reaction as oxidation and reduction are both taking place

  • Carbon is known as a reducing agent as it has reduced another substance (the zinc oxide)

  • Zinc oxide is known as an oxidising agent as it has oxidised another substance (the carbon)