When iron (Fe) reacts with oxygen (O2) in the air, iron oxide (Fe2O3) is formed.
Iron oxide is a form of rust and the chemical reaction is known as an oxidation reaction.
- In oxidation reaction, one atom loses electrons and transfers to another. Another atom gains the electrons. This process is also termed a "redox" reaction (which is short for reduction/oxidation).
- The actual iron rusting process is far more complicated than is shown on the video and we will cover it in another post.
- The rusting process is affected by water and the key reaction involves the formation of hydroxide ions as a result of oxygen in the air and moisture (h2o) combination.
- Rusting is therefore accelerated by the presence of moisture.
- In this reaction, for those in higher level chemistry, it is important to recognize which atoms are being oxidized and which atoms are being reduced.
- Redox reaction
Whenever there is oxidation, there is reduction and both chemical reactions must take place together.
- Atom that loses electrons - are oxidized.
- Atoms that gain electrons - are reduced.
In the iron oxide reaction
- Fe is being oxidized
- Oxygen is being reduced
Polar Covalent Bond
- The electronegative difference between iron and oxygen is around 1.61
- The bonding between iron and oxygen is a polar covalent bond but close to that of ionic bonds.