Need help with this Co2 problem

Question

1. The gas tank of a 2013 Honda Accord holds 17.2 gallons. How many pounds of carbon dioxide are produced by burning an entire tank of gas?

Answer 1

The answer to this problem depends on what is in the gas tank.  It has 17.2 gallons of what? Assuming it is regular gasoline (not ethanol, e.g.), and taking an average of say C8 (as in octane) as the average, and assuming a density of gas of 0.77 g/ml, and assuming complete combustion, yada yada, you can do the following calculations.  But note, most of these assumptions are probably NOT valid, and the question really can't be answered without more information.

2C8H18 + 25O2 ==> 16CO2 + 18H2O

17.2 gal x 3.785 liters/gal x 0.77 kg/liter = 50 kg C8H18

50 kg x 1000 g/kg x 1 mole C8H18/114 g = 439 moles

439 moles C8H18 x 16 moles CO2/2 moles C8H18 = 3512 moles CO2

3512 moles CO2 x 44 g/mole = 154,528 g CO2

154,528 g CO2 x 1 lb/454 g = 340 lbs of CO2