# In a chemical reaction, what is the number directly before each reactant, and each product?

May 6, 2017

$\text{The stoichiometric coefficient.........}$
$2 {H}_{2} \left(g\right) + {O}_{2} \left(g\right) \rightarrow 2 {H}_{2} O \left(l\right)$,
we have $\text{stoichiometric coefficients}$ of $2$, $1$, and $2$ respectively for dihydrogen, dioxygen, and the water molecules.