# How can chemical equations be classified?

Feb 12, 2015

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

Single Replacement
Format: $A B + C \to A C + B$

Double Replacement
Format: $A B + C D \to A C + B D$

Synthesis
Format: $A + B \to A B$

Combustion
Format: $A + {O}_{2} \to A O$
Oxygen (diatomic, subscript is 2) combined with a metal, to make the metal oxide. There is only one O in the oxide.

Decomposition
Format: $A B \to A + B$

Acid-Base
Format: $H A + B \to A + H B$
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.