A mole of gasoline will get you 1,303 kcal of energy. If we, somehow, figure out the number of moles of gasoline in 3 gallons, we'd be able to know the answer.
Step 1: First of all, there are 11,355 ml in 3 gallons assuming that there are 3785 ml in one gallon.
Step 2: Now, the density of octane is given as 0.7 g/ml, that is, there are 0.7 grams in 1 ml. This means that there are
Step 3: The molar mass of octane is
And so, if there is 1,303 kcal of energy from a mole of octane, then there