Question

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

Answer 1

`"60 such molecules........"`

Explanation:

You need a stoichiometrically balanced equation to represent the combustion:

`C_3H_8(g) + 5O_2(g) rarr 3CO_2(g) + 4H_2O(l)`

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.