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How did you arrive at 0.4 kWh of energy per 95 grams of CO2? Back of the envelope calculations. 95 grams of CO2 is equal to 2 moles of CO2. Assuming complete

How did you arrive at 0.4 kWh of energy per 95 grams of CO2? Back of the envelope calculations. 95 grams of CO2 is equal to 2 moles of CO2. Assuming complete combustion of Propane that is two moles of propane as well. Calorific value of propane is 2,200 kJ per mol. That turns out to be total energy output of 4,400 kJ per kilometer or 1.2 kWh. Which continuing with your line of thinking is 144 kW of power at 120km/h. This places an upper theoretical limit exceeding 110kW. Not saying this says anything about the actual burning characteristics of gasoline, just that the theoretical limit is higher.

ars 14y ago
Energy in gasoline: 36.6 kWh/US gallon http://en.wikipedia.org/wiki/Gasoline#Energy_content_.28high_and_low_heating_value.29 http://en.wikipedia.org/wiki/Gasoline#Energy_content_.28high... CO2 in gasoline: 19 lb, per gallon. http://www.fueleconomy.gov/feg/co2.shtml http://www.fueleconomy.gov/feg/co2.shtml (36.6kWh/19 lb) * 95 grams = 0.4 kilowatt hours http://www.wolframalpha.com/input/?i=%2836.6kWh%2F19+lb%29+*+95+grams http://www.wolframalpha.com/input/?i=%2836.6kWh%2F19+lb%29+*... Your error is: "Assuming complete combustion of Propane that is two moles of propane as well" Which is not correct. Propane has 3 carbon atoms, so it's actually 2/3 of a mole of propane. 1.2 kWh * 2/3 = .8 kWh. The difference is probably that gasoline has more carbon atoms, and fewer hydrogen ones. (C3H8 vs C8H18) Hydrogen is more energetic than carbon (about 4.3 times more according to http://en.wikipedia.org/wiki/Heat_of_combustion http://en.wikipedia.org/wiki/Heat_of_combustion ). A back of the envelope comparison of propane and gasoline: http://www.wolframalpha.com/input/?i=h+%3D+c+*+4.3%2C+x%3D++c*2%2Bh*8%2C+%28c*8%2Bh*18%29%2F4+%3D+.4 http://www.wolframalpha.com/input/?i=h+%3D+c+*+4.3%2C+x%3D++... got a result of .70 (vs .8). Probably because gasoline is not all C8H18 (octane). C6H14 is .9, so if gasoline is a 50/50 mixture of those two then you get .8 which is exactly what your back of the envelope shows.

ars 14y ago

Energy in gasoline: 36.6 kWh/US gallon http://en.wikipedia.org/wiki/Gasoline#Energy_content_.28high_and_low_heating_value.29 http://en.wikipedia.org/wiki/Gasoline#Energy_content_.28high... CO2 in gasoline: 19 lb, per gallon. http://www.fueleconomy.gov/feg/co2.shtml http://www.fueleconomy.gov/feg/co2.shtml (36.6kWh/19 lb) * 95 grams = 0.4 kilowatt hours http://www.wolframalpha.com/input/?i=%2836.6kWh%2F19+lb%29+*+95+grams http://www.wolframalpha.com/input/?i=%2836.6kWh%2F19+lb%29+*... Your error is: "Assuming complete combustion of Propane that is two moles of propane as well" Which is not correct. Propane has 3 carbon atoms, so it's actually 2/3 of a mole of propane. 1.2 kWh * 2/3 = .8 kWh. The difference is probably that gasoline has more carbon atoms, and fewer hydrogen ones. (C3H8 vs C8H18) Hydrogen is more energetic than carbon (about 4.3 times more according to http://en.wikipedia.org/wiki/Heat_of_combustion http://en.wikipedia.org/wiki/Heat_of_combustion ). A back of the envelope comparison of propane and gasoline: http://www.wolframalpha.com/input/?i=h+%3D+c+*+4.3%2C+x%3D++c*2%2Bh*8%2C+%28c*8%2Bh*18%29%2F4+%3D+.4 http://www.wolframalpha.com/input/?i=h+%3D+c+*+4.3%2C+x%3D++... got a result of .70 (vs .8). Probably because gasoline is not all C8H18 (octane). C6H14 is .9, so if gasoline is a 50/50 mixture of those two then you get .8 which is exactly what your back of the envelope shows.