ZIMSEC O Level Combined Science Notes:  The reduction process

  • Reduction is the opposite of oxidation
  • Reduction is the removal of oxygen from a substance/compound
  • It can also be the addition of oxygen
The reduction of copper. Image credit chemistrydemos.co.uk

The reduction of copper.

  • reducing agent removes oxygen or adds hydrogen
  • Metals cannot be yielded by heating their oxides
  • The metals have to be heated with a reducing agent
  • That will remove the oxygen from the oxide to yield the metal
  • The metal oxide is reduced into a metal
  • The reducing agent that can be used can be any of the following:
  • a metal that is higher up in the reactivity series when compared to the metal being extracted
  • hydrogen
  • or it could be carbon
  • All these can act as reducing agent
  • For example:
  • \text{copper oxide+hydrogen}\rightarrow\text{copper+water}
  • Hydrogen can be used to remove (displace)  oxygen from a compound
  • Carbon can also be used to reduce copper oxide yielding the copper
  • The equation can be written as:
  • \text{copper oxide+carbon}\rightarrow\text{copper+carbon dioxide}
  • A metal that is higher up in the reactivity series can be used to reduce a metal that is lower in the reactivity series
  • This is because the more reactive has a higher affinity for oxygen when compared to the metal that is lower in the series
  • The more reactive metal will thus “take” oxygen from the less reactive metal
  • The more reactive metal displaces the less reactive metal
  • This leaves the less reactive metal and an oxide of the more reactive metal
  • For example:
  • \text{iron oxide+aluminium}\rightarrow\text{iron+aluminium dioxide}
  • Aluminum is higher up in the reactivity series when compared to iron
  • The aluminum reduces the iron (III)  oxide to leave iron and aluminum oxide
  • A lot of heat is given out in the reaction
  • Exothermic reactions give out heat

To access more topics go to the Combined Science Notes page.

Quick NetOne, Telecel, Africom, And Econet Airtime Recharge

If anything goes wrong, chat with us using the chat feature at the bottom right of this screen