AP Chem
posted by Kai .
The heat of combustion of octane (C8H18) is 47.8 kJ/g and one gallon of C8H18 has a mass of 2620 g. If a car using octane is driven 10,000 miles in one year and gets 25 miles per gallon of octane, what is the total energy
consumption?
1. 5.01 × 107 kJ
2. 8.45 × 102 kJ
3. 34 × 107 kJ
4. 7.80 × 103 kJ
5. −13 × 103 kJ

This is WAY too much work to do for one problem but here is how you go about it.
10,000 miles driven @ 25 miles/gallon = how many gallons of octane. Convert gallons to liters and grams (but I don't see a density), Knowing grams should get you to kJ/g in connection with the equation of
2C8H18 + 17O2 ==>16CO2 + 18H2O