A gallon of gasoline doesn't even weigh 20lbs. How could it release 20lbs of anything? Honest question.
Gasoline is a chemical just like Carbon dioxide and both contain different molecules with different molecular weights. Based on a quick google search, gasoline is primarily made of hydrocarbons so it doesn't weigh much (6.3 lbs if we're talking about a gallon. 87% carbon and 13% hydrogen). When heated, all this chemical energy gets released: bonds (the hydrocarbons) break into carbon and hydrogen. Hydrogen recombines with o2 to form water. You get heat, water, and CO2. A carbon atom has a weight of 12 and oxygen is 16. So CO2 = 12 + (2)16 = 44. So if you want to know the amount of Co2 produced from a gallon of gasoline: 44 (total mw of CO2) / 12 (mw of Carbon) = 3.7. 6.3 X .87 = 5.5 then 5.5 x 3.7 = 20.
I think...
In general, any estimate on how much CO2 you release is kinda iffy cause the reaction itself isn't black and white. Sometimes hydrocarbons don't break if enough energy isn't put into the system or other gases are released.
The EIA calculates it like this: 2.4 g of Carbon in 1 gallon of gasoline which enough to make 8.8 g of CO2 x 0.99 (which accounts for carbon that doesn't react) and they get 19.5 pounds. So idk. It's close.
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This is so sad. Idk why people are so threatened by science. I'm legit considering doing my grad work outside of the US. Perhaps Canada.