The claim has been bandied about in the news Media that a light jet produces about 40 tons of co2.(Al Gores private jet on a cross country flight) I doubt it because, for example, a Learjet 31A has fuel capacity of 2.062 tons, and total takeoff weight of 8.5 tons. This means, the co2 produced weighs 19 times more than the fuel itself, and 4.7 times more than than the whole plane. This is actually good for global vegitation,One greeny professor on the net, tried to explain it by asserting that every atom of exhaust cabon combined with 2 atoms of oxygen, added the atomic weights etc., not sure how he knows this is exactly what happens, it would mean there is never any carbon in the air at all. There should be a way to test this, by exhausting a motor into a huge sealed container (semi trailer?) and examining the result with a spectrograph or gas chromatograph or something. Weighing the container before and after won't work because the oxygen inside stays the same, actually the engine is adding its own oxygen to the mix as well, maybe someone can think up an idea how to test this goofy idea, I just don't beleive it.
So, to reiterate, a jet, burning 8.5 tons of fuel will produce 40 tons of CO2.

Jet A is a combination of hydrocarbons, but lets be generous to the calculations and limit it to C10H22.

So, your combustion reaction is:

2C10H22 + 31 O2 = 20 CO2 + 22 H2O

CO2 weighs 44 grams per mole, while the fuel weighs 142 grams per mole.

Thus, the above reaction will transform 284 grams of JetA (and 992 grams of oxygen) into 880 grams of CO2 and 396 grams of water vapour.

Of course, higher fractions in the fuel will increase these values.

No, even if you do the math under ideal conditions using all of the plane's weight as fuel, it still doesn't add up to 40 tons US.

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...not sure how he knows this is exactly what happens, it would mean there is never any carbon in the air at all.

That's how you figure out the math under ideal conditions. The carbon that's blamed for global warming isn't free, but is instead reacted with oxygen and other elements.

EDIT: Roofin, I used a different hydrocarbon for my calculations, but the assumption I made that the whole plane's takeoff weight was fuel more than makes up for that.

The fact remains that which "light jet" wasn't specified.

An EMB-135LR holds about 12,000 pounds of fuel and will thus generate almost 40,000 pounds of CO2, so even that smallish jet is halfway to making the "40 tons" accurate.

Ideal conditions? Research the combustion efficiency of typical Gas turbine. Very, very little fuel doesn't burn.

Don't forget also, that by definition, a "heavy" jet is an aircraft capable of a takeoff weight of 300,000 lbs or more, so even a 757-300 is not a "heavy" jet.

As I said, this leaves quite a large range for what a "light jet" might entail when the statistic was first issued.

It could very easily have been referring to his Air Force Two flights, for all we know.

It's the media. They probably got statistics by simulating what it would be if he flew a plane made out of depleted uranium

While i doubt the 40 ton of CO2 is accurate you must take into a account that a plane like a learjet 31A that you used in your exemple has a range of 2695 km with the 2 ton of fuel in its tank, so for a cross country flight you will most likely need to refuel and burn more then 2 ton of fuel in total.

A learjet 31A was cited as an example in the original question,(for roofinguy's info). It's also self understood that if you keep refueling,eventually it will produce 40 tons of CO2. which is food for trees and agricrops etc. There must be a physical way to test this, which would be good entertainment for Mythbusters audience. Chemical formulas and math work on paper, but not always predict reality, see the history of Astronomy, and particle physics, engineers predicted,in the 50's or 60's that a dragster could never achieve 200 mph in a 1/4 mile, because of the "coefficiant of friction" on rubber tires (Hot Rod magazine). Their formula was correct, but it was merely a formula, without any common sense.

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Chemical formulas and math work on paper, but not always predict reality,

You don't want to see the equations that do accurately predict reality. Those haunt the nightmares of experienced mathematicians.

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Originally posted by willyger:
A learjet 31A was cited as an example in the original question,(for roofinguy's info). It's also self understood that if you keep refueling,eventually it will produce 40 tons of CO2. which is food for trees and agricrops etc. There must be a physical way to test this, which would be good entertainment for Mythbusters audience. Chemical formulas and math work on paper, but not always predict reality, see the history of Astronomy, and particle physics, engineers predicted,in the 50's or 60's that a dragster could never achieve 200 mph in a 1/4 mile, because of the "coefficiant of friction" on rubber tires (Hot Rod magazine). Their formula was correct, but it was merely a formula, without any common sense.

This isn't that big an issue. The math is simple if the basic data is known. You need to know the fuel consumed for a trip, the actual portion of fuel mass that's carbon and add the mass of oxygen required to turn it all into CO2. It's just that basic. Turbines run very lean fuel ratios and 99.+ % combustion efficiency. Essentially no carbon in the fuel doesn't end up as CO2. The basic data on aircraft performance, fuel composition, a basic chemistry equation will give a highly accurate result. If you know the fuel consumption for a given trip and balance the chemical reaction formula the answer is valid. There's really no drag racing analogy influence to consider.

It is a huge issue, 1000's of planes spewing out 40 to 200 tons of CO2 per flight. The math may be simple, but can you prove that every atom of carbon combines with 2 atoms of oxygen? The formula for CO2 simply means it's the formula for CO2, but if you inject 1 litre of C and 2 litres of O together, will every atom form CO2, or will there be free carbon and free oxygen left over, especially with other elements present.
There was no analogy to drag racing, It was an analogy to formulas,the coefficiant of frictian formula and the formula that asserts that a gallon of fuel (6.5 lbs.), when run through an engine, will produce about 130 lbs of CO2.
In fact, if true, dry ice manufacturers could discard their current CO2 generators and simply install a GE90-115B jet engine, run it for 6 hours and generate 2,580 toms or so of CO2 which should last a long time,and make a lot of dry ice, and the engine would be shut down most of the year if not more.
This whole thing sounds suspiciously akin to perpetual motion,(getting something for nothing) if CO2 is so abundant and easy to make, perhaps the forest service should set up a jet engine at the upwind side of some forests, run it periodically, and watch the forests grow.
CO2 in the atmosphere is about 350 PPM. All of the inert gases make up only 1% of the atmosphere, of this 1%, CO2 is only only 0.0350 or .00035% of the atmosphere. Mars atmosphere is about 95% CO2, WOW,it must really be hot.

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Originally posted by willyger:
It is a huge issue, 1000's of planes spewing out 40 to 200 tons of CO2 per flight. The math may be simple, but can you prove that every atom of carbon combines with 2 atoms of oxygen? The formula for CO2 simply means it's the formula for CO2, but if you inject 1 litre of C and 2 litres of O together, will every atom form CO2, or will there be free carbon and free oxygen left over, especially with other elements present.
There was no analogy to drag racing, It was an analogy to formulas,the coefficiant of frictian formula and the formula that asserts that a gallon of fuel (6.5 lbs.), when run through an engine, will produce about 130 lbs of CO2.
In fact, if true, dry ice manufacturers could discard their current CO2 generators and simply install a GE90-115B jet engine, run it for 6 hours and generate 2,580 toms or so of CO2 which should last a long time,and make a lot of dry ice, and the engine would be shut down most of the year if not more.
This whole thing sounds suspiciously akin to perpetual motion,(getting something for nothing) if CO2 is so abundant and easy to make, perhaps the forest service should set up a jet engine at the upwind side of some forests, run it periodically, and watch the forests grow.
CO2 in the atmosphere is about 350 PPM. All of the inert gases make up only 1% of the atmosphere, of this 1%, CO2 is only only 0.0350 or .00035% of the atmosphere. Mars atmosphere is about 95% CO2, WOW,it must really be hot.

If you can't understand the responses posted already, then I certainly can't explain it to you. I worked in the turbine industry for nearly 15 years as a test engineer. I'm well aware of what the combustion products are. Don't know what sort of further proof would convince you. It's well established that complete combustion of hydrocarbon compounds results in CO2 and H20 as combustion products. Incomplete combustion can result in partial combustion products such as carbom particulates (soot), CO, and methane radicals.

The rest of your response is mostly silly nonsense showing very little understanding. Maybe it was meant at a joke.

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Originally posted by willyger:
It is a huge issue, 1000's of planes spewing out 40 to 200 tons of CO2 per flight. The math may be simple, but can you prove that every atom of carbon combines with 2 atoms of oxygen? The formula for CO2 simply means it's the formula for CO2, but if you inject 1 litre of C and 2 litres of O together, will every atom form CO2, or will there be free carbon and free oxygen left over, especially with other elements present.
There was no analogy to drag racing, It was an analogy to formulas,the coefficiant of frictian formula and the formula that asserts that a gallon of fuel (6.5 lbs.), when run through an engine, will produce about 130 lbs of CO2.
In fact, if true, dry ice manufacturers could discard their current CO2 generators and simply install a GE90-115B jet engine, run it for 6 hours and generate 2,580 toms or so of CO2 which should last a long time,and make a lot of dry ice, and the engine would be shut down most of the year if not more.
This whole thing sounds suspiciously akin to perpetual motion,(getting something for nothing) if CO2 is so abundant and easy to make, perhaps the forest service should set up a jet engine at the upwind side of some forests, run it periodically, and watch the forests grow.
CO2 in the atmosphere is about 350 PPM. All of the inert gases make up only 1% of the atmosphere, of this 1%, CO2 is only only 0.0350 or .00035% of the atmosphere. Mars atmosphere is about 95% CO2, WOW,it must really be hot.

The definition of combustion states that one carbon atom will combine with two oxygen atoms and also water is produced. That is part of the definition. You are right to say that if you put free carbon and elemental oxygen in a container it wont necessarily all, if any, react. In the situation of combustion, or this case, a jet engine. It will react and there will be no "free carbon" remaining.

On the flipside, jet engines aren't 100% efficient. I mean that not all of the fuel is combusted so part of the exhaust is hydrocarbons.

Also, the media uses the word "tons" when describing CO2 emissions. This is a play on the English language. We hear tons and assume that is an extremely large amount, because one ton is 2,000lbs of CO2. That is a large amount. What you need to look at more over is parts per million (ppm) or the percentage of the atmosphere is resulted from this exhaust. So 1 ton of CO2 could be less than one millionth of a percent of the atmosphere.

Keep that in mind when discussing global warming and greenhouse gas emissions. Also, the majority of greenhouse gasses that will cause an actual change in the atmosphere is water vapor, not CO2.

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Originally posted by willyger:
It is a huge issue, 1000's of planes spewing out 40 to 200 tons of CO2 per flight. The math may be simple, but can you prove that every atom of carbon combines with 2 atoms of oxygen? The formula for CO2 simply means it's the formula for CO2, but if you inject 1 litre of C and 2 litres of O together, will every atom form CO2, or will there be free carbon and free oxygen left over, especially with other elements present.
There was no analogy to drag racing, It was an analogy to formulas,the coefficiant of frictian formula and the formula that asserts that a gallon of fuel (6.5 lbs.), when run through an engine, will produce about 130 lbs of CO2.
In fact, if true, dry ice manufacturers could discard their current CO2 generators and simply install a GE90-115B jet engine, run it for 6 hours and generate 2,580 toms or so of CO2 which should last a long time,and make a lot of dry ice, and the engine would be shut down most of the year if not more.
This whole thing sounds suspiciously akin to perpetual motion,(getting something for nothing) if CO2 is so abundant and easy to make, perhaps the forest service should set up a jet engine at the upwind side of some forests, run it periodically, and watch the forests grow.

Like I said, "You don't want to see the equations that do accurately predict reality. Those haunt the nightmares of experienced mathematicians."

The equations that have been shown, while they don't predict the exact composition of the exhaust, are very good at telling what the general mixture will be. The equations that would predict the exact nature would take more memory and data than your computer can handle. Even if you're working from a supercomputer, no computer on earth has the capabilities to do an exact calculation of anything you've asked so far. Generalities are all you're going to get. And smarti listed some of the common impurities in the exhaust. There are probably a few hundred others altogether, with likely a dozen or so stable molecules present.

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Originally posted by willyger:
It is a huge issue, 1000's of planes spewing out 40 to 200 tons of CO2 per flight.

I don't see how you can say that 40-200 tons of CO2 per flight is a huge issue without comparing it to an alternative mode of transportation. How many tons of CO2 would 120 cars traveling cross country produce? Compare that to a 737's cross country flight and I bet the airplane will look much nicer to the environment. Numbers mean nothing without a suitable comparison.

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The fact remains that which "light jet" wasn't specified.

An EMB-135LR holds about 12,000 pounds of fuel and will thus generate almost 40,000 pounds of CO2, so even that smallish jet is halfway to making the "40 tons" accurate.

'
Forgive my ignorance, math is not my strong suit. How is it that you can get more out of the fuel than there is fuel? If there is only six tons of raw material, how do you end up with twenty tons of waste material?

In principle, it's because the atmosphere is providing 2 Os for every C contained in the fuel. The combustion happens because vast amounts of air are going into the engines, so that the total mass of the exhaust can exceed that of the fuel in the tanks because the mass of the oxygen can't be neglected because it contributes to the reaction. If the fuel was being burned in a rocket engine, the oxidizer would have to be provided from a tank, but it's all around a jet engine waiting to go into the intake.

I probably wasn’t clear enough in my original post, for those who are biased and use the technique of trying to make facts fit a preexisting concept, as opposed to following the evidence wherever it leads.
Since no one mentioned CO, O3, or Nox, as emissions, they most likely have derived their answers from a method that uses a certain lab apparatus to heat a hydrocarbon , applies pure oxygen , and runs it through 2 filters which measure CO2only, and H2Oonly, and exhausting unused oxygen. They could have used a model airplane engine and obtained a result closer to reality.
This was my analogy to using the coefficient of friction equation to predict how fast a dragster could ever go in a ¼ mile, get it? They were wrong, and the above lab formula cannot possibly predict exactly what an air breathing engine will emit, when breathing atmospheric air, not pure oxygen.
The above lab experiment is using a controlled situation, using only oxygen, and a hydrocarbon, to predict the emissions output of an engine which breaths atmospheric air which is 79 % nitrogen and and contains hydrogen etc. and contains plenty of sulfur and other reactive chemicals especially near the 1500 active volcanoes on the planet , In fact , the state requires an emissions test for CO, O3 and Nox, also, I think engines burning hydrocarbons using atmospheric air will emit H2O2, CH20, C3H6O3, C20H28O2, H2SO4, HNO3, CO, ( CO is an emission used to commit suicide, so it must be an actual fact, get it?) .
So, maybe try explaining, according to the greenies why an AIR breathing engine only emits CO2 and H2O, and no CO, O3, CH2O, etc.
My original post was meant to help think up a small scale experiment to test a real engines CO2 output, because I seriously doubt the greenie version , which is based on a lab apparatus using pure oxygen

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Originally posted by TaurusUW:

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Originally posted by willyger:
It is a huge issue, 1000's of planes spewing out 40 to 200 tons of CO2 per flight.

I don't see how you can say that 40-200 tons of CO2 per flight is a huge issue without comparing it to an alternative mode of transportation. How many tons of CO2 would 120 cars traveling cross country produce? Compare that to a 737's cross country flight and I bet the airplane will look much nicer to the environment. Numbers mean nothing without a suitable comparison.

I should have said 40 to 5000 toms. It's the greenies and the UN and EPA and Congress that are saying it, because they are intending to impose a new tax on us in the form of carbon offsets, which are based on nonsense, because they can't possibly prove it. willyger