Your reaction will produce
Start with the balanced chemical equation for the combustion of propane
The most important tool in your arsenal when dealing with stoichiometry problems is the mole ratio. The mole ratio tells you in what exact proportions the reactans will mix and exactly how much products their reaction will produce.
In this case, the mole ratio between oxygen and carbon dioxide is
Simply put, the number of carbon dioxide moles produced will always be exactly 3/5 times smaller than the number of oxygen moles that react.
An important aspect is that you have excess propane, which means that oxygen will be the limiting reagent
Determine how many moles of oxygen you have by using its molar mass
Now use the aforementioned mole ratio to determine how many moles of
Finally, use carbon dioxide's molar mass to determine the mass produced