Carbon, Hydrogen, and OXYGEN: Why didn’t someone tell me?

I recently read that burning one gallon of gasoline releases about 19 lbs of carbon dioxide.

The mass on either side of a chemical reaction must balance, so I thought to myself, “If a gallon of fuel weighs 6 lbs, where is the other 13 lbs coming from?”

Well, it turns out that the additional weight is from the 21 lbs of oxygen that your car sucks from the atmosphere to burn that gallon of gas! Your car also spits out one gallon (8 lbs) of water in the process. 21 lbs of oxygen fills about four phone booths (~250 cu. ft.), and 19 lbs of carbon dioxide fills about two and a half phone booths (~150 cu. ft.). If your fuel economy is 25 mpg, then the above quantities occur every 25 miles you drive.

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Chartjunk: U-Haul CO2

Wow! Talk about chartjunk!

This chart shows that on a 1,000 mile trip, a U-Haul truck running on gasoline will emit 2,774 lbs of carbon dioxide, while some other truck running on diesel fuel will emit 2,798 lbs. On this trip, the U-Haul will emit 24 lbs, or a whopping 0.8%, less carbon dioxide! Aside from questioning the comparison of a gasoline truck to a diesel truck, this difference is so tiny (less than one percent) that its meaning is quickly swallowed up by any other variables in the system (age of truck, miles per tank, driving habits, fuel cost, total energy efficiency, weather). The glaring offense is the fact that the other truck’s dark cloud of smoke appears to have nearly three times greater area than the lighter U-Haul cloud. So, visually, the chart implies that U-Haul emits 60% less, while the dubious numbers show that the difference is less than 1%; this is a visual distortion of extreme proportions. Mysteriously, a trip of 999 miles or 1,001 miles yields a difference of only 23 lbs.



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