Specific types of reactions.
Precip: a solid or precip. forms upon mixing two (aq) solutions.
Acid-Base: Water forms upon mixing an acid and a base.
Gas evo: A gas forms upon mixing two (aq) solutions.
Redox: e- are transferred from one substance to another.
Combustion: A substance reacts w/ O2, emitting heat, and forming an oxygen-containing compound and, in many cases, water.