Question

Compare the emissions of a propane burning car to that of a car burning regular gasoline. Which pumps out more pollution? For simplicity, assume gasoline to be 100% octane (2,2,4- trimethylpentane).

1. Write and balance a combustion formula for each type of engine. (Don't forget phase signs!) Fuel + O2 → CO2 + H₂O​

Answer 1

The combustion reaction for propane can be represented as follows:

C3H8 (g) + 5O2 (g) → 3CO2 (g) + 4H2O (l)

The combustion reaction for gasoline (2,2,4-trimethylpentane) can be represented as follows:

C8H18 (g) + 25/2 O2 (g) → 8CO2 (g) + 9H2O (l)

In general, both types of engines produce CO2 and H2O as products of combustion. However, gasoline releases more CO2 per unit of fuel burned compared to propane, due to its higher carbon content. So, a car burning gasoline would produce more emissions of CO2 compared to a car burning propane.