A website promoting the use of alternative energy vehicles and hybrid technologies claims that, \"A typical automobile in the USA uses about 40 gallons of gasoline every month, producing about 750 lbs of carbon dioxide.\" To determine the truth of this statement, calculate how many pounds of carbon dioxide are produced when 40.00 gallons of gasoline are combusted. Assume that the primary ingredient in gasoline is octane, C8H18(l), which has a density of 0.703 g·mL–1..

2 answers

1 gallon = 3.785 L; therefore,
40 gallons = about approx 151 L - approx 151,000 mL
Use density to convert to grams; mass = volume x density = approx 1.06E5 grams.
mols C8H18 = grams/molar mass = approx 900
2C8H18 + 25O2 ==> 16CO2 + 18H2O
Convert mols octane to mols CO2; that is
900 mols octane x (16 mols CO2/2 mol C8H18) = 900 x (16/2) = 900*8 = approx 7200 grams CO2
Convert to lbs. There are about 454 g/lb.
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