# How many molecules of carbon dioxide will be produced if 20 molecules of propane react?

May 1, 2017

$\text{60 such molecules........}$

#### Explanation:

You need a stoichiometrically balanced equation to represent the combustion:

${C}_{3} {H}_{8} \left(g\right) + 5 {O}_{2} \left(g\right) \rightarrow 3 C {O}_{2} \left(g\right) + 4 {H}_{2} O \left(l\right)$

So are charge and mass balanced here?

Clearly, the reaction specifies 3 equiv of carbon dioxide per equiv of propane. If we start with 20 molecules of propane, these will necessarily be 60 carbon dioxide product molecules upon complete combustion.