Combustion
When oxygen combines with another compound to form water and carbon dioxide. These reactions are exothermic, meaning they produce heat.
Synthesis
When two or more simple compounds combine to form a more complicated one.
A + B → AB
For example, iron and sulfur combine in a synthesis reaction to form iron (II) sulfide:
8Fe + S8 → 8FeS
Decomposition
The opposite of a synthesis reaction - a complex molecule breaks down to make simpler ones.
Single displacement (Substitution)
When one element trades places with another element in a compound
Double displacement (Metathesis)
When the anions and cations of two different molecules switch places, forming two entirely different compounds.
Acid-base
A special kind of double displacement reaction that takes place when an acid and base react with each other.