Oxidation & Reduction (WJEC GCSE Chemistry: Combined Science)

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Oxidation & Reduction

Redox reactions in terms of oxygen

  • Oxidation and reduction take place together at the same time in the same reaction
  • These are called redox reactions
  • 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 compound
  • The following reaction between zinc oxide and carbon is an example of redox reaction:

The reaction between zinc oxide and carbon

2M~Ja4O8_oxidation-and-reduction---oxygen

Both reduction and oxidation has occurred in this reaction so it is classed as a redox reaction

  • In this reaction, the zinc oxide has been reduced since it has lost oxygen
  • The carbon atom has been oxidised since it has gained oxygen
  • In the blast furnace a reaction between iron(III) oxide and carbon monoxide takes place
  • This is also classed as a redox reaction

The reaction between iron(III) and carbon monoxide

BWChinGG_reduction-of-ironiii-oxide

Carbon is above iron in the reactivity series so is able to reduce iron from iron(III) oxide

Examiner Tip

You must be precise about your descriptions of oxidation and reduction. In the blast furnace, it is the iron(III) oxide that is reduced and not iron. Students often get this wrong so take care to check the equation. 

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Philippa

Author: Philippa

Expertise: Chemistry

Philippa has worked as a GCSE and A level chemistry teacher and tutor for over thirteen years. She studied chemistry and sport science at Loughborough University graduating in 2007 having also completed her PGCE in science. Throughout her time as a teacher she was incharge of a boarding house for five years and coached many teams in a variety of sports. When not producing resources with the chemistry team, Philippa enjoys being active outside with her young family and is a very keen gardener.