Question

Question #9245f

Answer 1

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 `0.7 * 11355 = 7948.5 \ \text{grams}` of octane.

Step 3: The molar mass of octane is `114 g`, and so we have `69.72` moles of octane.

And so, if there is 1,303 kcal of energy from a mole of octane, then there `1303 \times 69.72 \approx 90850 \ \text{kcal}` of energy would be released with 69.72 moles.