Question

How can chemical equations be classified?

Answer 1

There are six main types of equations, grouped by how they're formatted and what kind of reaction occurs.

Single Replacement
Format: `AB + C -> AC + B`

Double Replacement
Format: `AB + CD -> AC + BD`

Synthesis
Format: `A + B -> AB`

Combustion
Format: `A + O_2 -> AO`
Oxygen (diatomic, subscript is 2) combined with a metal, to make the metal oxide. There is only one O in the oxide.

Decomposition
Format: `AB -> A + B`

Acid-Base
Format: `HA + B -> A + HB`
Hydrogen is transferred from one to the other.

If any of these formats don't make sense, the best resource is your textbook used in class. The Acid-Base you may or may not use with the rest of these, it fits more into the Acids and Bases topic. Remember to balance all equations.