How is this possible?!

B

BCO

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I'm doing an article for my blog and have found something that's confusing me:

I'm looking at this document http://oee.nrcan.gc.ca/transportation/personal/pdfs/most-efficient-vehicles-2007.pdf which shows the most fuel efficient cars in Canada for 2007.

Based on the figures they quote, I'm getting a figure of 2.4kg of carbon emitted for every litre of petrol burned. How exactly can a litre of fuel (which must weigh less than 1 kg) burn up and make over 2kg of CO2?
 
BlueCollar said:
I'm doing an article for my blog and have found something that's confusing me:

I'm looking at this document http://oee.nrcan.gc.ca/transportation/personal/pdfs/most-efficient-vehicles-2007.pdf which shows the most fuel efficient cars in Canada for 2007.

Based on the figures they quote, I'm getting a figure of 2.4kg of carbon emitted for every litre of petrol burned. How exactly can a litre of fuel (which must weigh less than 1 kg) burn up and make over 2kg of CO2?
Click to expand...

Bear in mind that you're not including the oxygen there. I don't really know the relevant quantities, only that the fuel:air mixture for petrol combustion is 1:14 - so 14 parts of air to 1 part fuel. Dunno if that ration works by mass or volume though.
 
Just like you can get fat by breathing :-)

Combustion will take oxygen out of the atmosphere, combine it with the carbon (in the petrol) and add the combined weight of oxygen + fuel to the atmosphere as carbon dioxide and carbon monoxide.
 
Deenem said:
Just like you can get fat by breathing :-)

Combustion will take oxygen out of the atmosphere, combine it with the carbon (in the petrol) and add the combined weight of oxygen + fuel to the atmosphere as carbon dioxide and carbon monoxide.
Click to expand...

That's what I suspected. It's amazing that the mass of the emissions is so much greater though.
 
The only answer I can come up with is that they are measuring the total amount of carbon released into the environment by the use of 1l of petrol.
This would include the carbon used in the production and transportation of that litre of petrol.
Otherwise I am stumped.
 
One Carbon (from the fuel) + 2 Oxygen's (from the atmosphere) = 1 CO2 so a litre of fuel sucks up almost twice it's weight in oxygen from the atmosphere.

Fuel is a hydro-carbon, so there's a bit of hydrogen as well that gets converted to water. (You see the water vapour coming out of exhausts on cold days)
 
If that is the case, they probably take into account the carbon cost of producing the petrol
 
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