What is the difference between oxidation and reduction?

In chemistry if a substance is oxidised it loses electrons in a reaction.

If a substance is reduced it gains electrons in a reaction.

A reaction that has both oxidation and reduction within it is called a REDOX reaction. We can write REDOX reactions as half equations - this can make it easier to see what is going on in the reaction.

For example, Zinc oxide can be reacted with Carbon to extract Zinc:

2ZnO + C --> 2Zn + CO₂

In this reaction one of the substances is oxidised and one is reduced. If we write them as half equations:

Zn⁺ + e^- --> Zn

C --> C²⁺ + 2e^-

These equations show that Zn has GAINED an electron to have a neutral charge - there for it has been REDUCED.

Carbon has LOST 2 electrons to become C²⁺ - therefore it has been OXIDISED.