# What is a coefficient and how is it applied in chemistry?

Nov 30, 2016

Consider a simple combustion reaction:

$C {H}_{4} \left(g\right) + 2 {O}_{2} \left(g\right) \rightarrow C {O}_{2} \left(g\right) + 2 {H}_{2} O \left(l\right)$

#### Explanation:

This is a stoichiometrically balanced equation: garbage in equals garbage out, and for every reactant particle there is a corresponding product particle.

The $\text{stoichiometric coefficient}$ of methane gas is $1$, that of dioxygen gas is $2$, that of carbon dioxide $1$, and that of water $2$.

In other words the $\text{stoichiometric coefficient}$ is the $\text{number of EQUIVALENTS}$ of stuff that react or occur as products. Capisce?

Teachers go to great lengths in explaining how to balance chemical equations. You have to be able to manipulate the coefficients so that the reaction balances stoichiometrically, and thereby reflects reality.