quote:

Originally posted by dogaway:
As another complete layman on the issue of climate change, I have a question about about CO2....if you oxidize a kilogram of carbon how much CO2 do you have? 3kg?
stuff about global warming often says how much space a ton of CO2 takes up, or whatever. But what does it take to make a ton of CO2 in the first place? a third of a ton of carbon? this is a question thats been bugging me for a while.

I hope someone will jump in if I've got this wrong, but carbon has an atomic weight of 12 and oxygen's is 16. Each C02 molecule therefore has a molar mass of 44 (12 + 2*16), so I assume that 1 tonne of CO2 would be made up of 273 kg or carbon and 727 kg of oxygen.

Or am I mixing up atomic weights and molar masses when I shouldn't?

quote:

Originally posted by APL:
You will be lucky to get a meaningful answer to this question because most of the figures associated to CO2 and global warming revolve around estimates which are then taken as facts.

Why? It seems a simple enough question in principle. Of course, you take it as an invitation to go off on another conspiracy-based excursion.

Anyway, what answer do you have to the question?

quote:

Originally posted by TrueSceptic:
Climate scientists. You seem content to use or dismiss their work as it suits you.

The issue is whether present warming is cyclic (due to natural causes only) or acyclic (due to our contributions in addtition to natural ones). The evidence is that present warming is acyclic.

What evidence? Putting fragments of scientific research together and then linking these fragments in such a way as to conclude CO2 causes GW requires leaping assumptions and is unscientific.

Additionally, as I have posted before, it is extremely difficult to distinguish the fact from the fiction thanks to the politics. And when those of us look a little deeper into the subject other than the PC science we find huge amount of assumption, 'sexing up' and even some fiddling of the facts along the way - and yes if such goings on were to be happening to support the anti-AGW viewpoint I would equally condemn that practice too - but then I can do that because I am a AGW sceptic - pro-AGW on the other hand have to stick rigidly to their beliefs so that they refrain from becoming or appearing to be sceptical.

quote:

Originally posted by TrueSceptic:
Lame. One cold day (or week or month or year) doesn't disprove GW any more than a hot one proves it.

Careful now you are beginning to sound like a true sceptic.

quote:

Originally posted by APL:

What evidence? Putting fragments of scientific research together and then linking these fragments in such a way as to conclude CO2 causes GW requires leaping assumptions and is unscientific.

Additionally, as I have posted before, it is extremely difficult to distinguish the fact from the fiction thanks to the politics. And when those of us look a little deeper into the subject other than the PC science we find huge amount of assumption, 'sexing up' and even some fiddling of the facts along the way - and yes if such goings on were to be happening to support the anti-AGW viewpoint I would equally condemn that practice too - but then I can do that because I am a AGW sceptic - pro-AGW on the other hand have to stick rigidly to their beliefs so that they refrain from becoming or appearing to be sceptical.

Usual conspiracy theory drive tripe.

quote:

Careful now you are beginning to sound like a true sceptic.

You have no clue what it means.

quote:

I hope someone will jump in if I've got this wrong, but carbon has an atomic weight of 12 and oxygen's is 16. Each C02 molecule therefore has a molar mass of 44 (12 + 2*16), so I assume that 1 tonne of CO2 would be made up of 273 kg or carbon and 727 kg of oxygen.

Or am I mixing up atomic weights and molar masses when I shouldn't?

Looks right to me.

Furthermore, petrol and oil is 80-90% carbon by mass. So a tonne of oil-based fuel gives you about 3 tonnes of carbon dioxide.

quote:

Originally posted by TrueSceptic:
Anyway, what answer do you have to the question?

The answer to his question is here: http://www.hydrogen.co.uk/h2_now/journal/articles/2_global_warming.htm

But please note when reading this the assumptions - i.e. 'the burning of 7 billion tons of carbon' and 'Amazon rain forest is absorbing 1.7 ppm' and it goes on.

Also note the switching between ppm and mass, and do they mean ton as in 2,240 lb, 2000lb, or 1000kg who knows.

Finally the next question should be what is the relationship between the mass of CO2 and temperature?

quote:

Originally posted by Steve_M:

quote:

I hope someone will jump in if I've got this wrong, but carbon has an atomic weight of 12 and oxygen's is 16. Each C02 molecule therefore has a molar mass of 44 (12 + 2*16), so I assume that 1 tonne of CO2 would be made up of 273 kg or carbon and 727 kg of oxygen.

Or am I mixing up atomic weights and molar masses when I shouldn't?

Looks right to me.

Furthermore, petrol and oil is 80-90% carbon by mass. So a tonne of oil-based fuel gives you about 3 tonnes of carbon dioxide.

Yep. A ton of coal gives you 3 tons of CO2. There's centuries worth left and it's a real pollutant - particles, radioactivity and of course CO2.

quote:

Originally posted by APL:
The answer to his question is here: http://www.hydrogen.co.uk/h2_now/journal/articles/2_global_warming.htm

But please note when reading this the assumptions - i.e. 'the burning of 7 billion tons of carbon' and 'Amazon rain forest is absorbing 1.7 ppm' and it goes on.

Also note the switching between ppm and mass, and do they mean ton as in 2,240 lb, 2000lb, or 1000kg who knows.

Finally the next question should be what is the relationship between the mass of CO2 and temperature?

So their answer is the same as mine. I thought it was "too easy" so I'm glad to get this and Steve_M's confirmation.

Yes, it's odd that they use tons (I assume not a short ton) instead of the metric tonne, but ITOH the difference is small at 1.6% so it doesn't matter with rough calculations.

I think the burning of carbon can be estimated quite well but the role of rain forests and other vegetation in absorbing CO2 must be less precise.

quote:

Originally posted by Steve_M:
Furthermore, petrol and oil is 80-90% carbon by mass. So a tonne of oil-based fuel gives you about 3 tonnes of carbon dioxide.

Ahh! Could this be why pro-AGW prefer weight to molecular numbers.

Petrol and oil comprises of C5H12 to C18H38 in other words oil and petrol is (roughly) one part carbon to two parts hydrogen - that not 80-90% now is it.

quote:

Originally posted by realprimate:
Yep. A ton of coal gives you 3 tons of CO2. There's centuries worth left and it's a real pollutant - particles, radioactivity and of course CO2.

Hmmm... You assume coal is 100% carbon - no surprise there then 'sexing up' the facts again.

I hope those new to this game are beginning to see how exaggerated the pro-AGW claims are.

quote:

Originally posted by TrueSceptic:
I think the burning of carbon can be estimated quite well but the role of rain forests and other vegetation in absorbing CO2 must be less precise.

Really - so where were you then as a 'true sceptic' putting right Steve_M's and realclimate's claims as to the amounts of carbon in fossil fuels.

Or is it you that holds the one-sided viewpoint you claim others to have?

APL

quote:

Ahh! Could this be why pro-AGW prefer weight to molecular numbers.

Petrol and oil comprises of C5H12 to C18H38 in other words oil and petrol is (roughly) one part carbon to two parts hydrogen - that not 80-90% now is it.

I'm afraid you are wrong on this stuff. You have to work by atomic weight ie carbon =12 Hydrogen =1. Certainly basic O-level chemistry in my day.

so C5H12 is 60 carbon + 12 Hydrogen by weight so carbon = 60/72 ie 83% as the carbon and hydrogen numbers get bigger so the carbon % increases even more.

I'm a sceptic because I'm trying to find reasonable scientific holes in the AGW argument. I wish other sceptics would also instead of resorting to mudslinging tit-for-tat as they do a disservice to the process.

I try to raise observations I've made in the literature or from these posts that on the surface seem to contradict the "it's all down to anthropic CO2 hypothesis", whether science or presentational dirty tricks. But I try to do it within correct basic science to the best of my ability because it's the AGW argument that is potentially adversely influencing our society based on some sound science, some uncertainties and a hell of a lot of propaganda and projections that seem sometimes not to consider the falability of the methods used and other possible elements in the mix.

quote:

Originally posted by TrueSceptic:
So their answer is the same as mine. I thought it was "too easy" so I'm glad to get this and Steve_M's confirmation.

When does 44 = 44/12?

When does 273kg = 367kg?

quote:

Originally posted by Son of Mulder:
I'm afraid you are wrong on this stuff. You have to work by atomic weight ie carbon =12 Hydrogen =1. Certainly basic O-level chemistry in my day.

so C5H12 is 60 carbon + 12 Hydrogen by weight so carbon = 60/72 ie 83% as the carbon and hydrogen numbers get bigger so the carbon % increases even more.

Not so - my point is that when determining the amount of CO2 created from the amount of carbon (which is what was being done here) weight has nothing to do with it at all - it is the number of carbon molecules that matters and not how much they weigh.

Using weight as you clearly point out gives a large percentage but that inaccurately inflates the number of carbon molecules in the substance that will be converted into CO2.

Taking the 80-90% of fuel by weight is carbon argument to calculate the amount of CO2 created when 1 tonne of fuel burns suggests 800-900kg of carbon is create from a substance that has only one carbon molecule in three and it is only this one carbon molecule that goes to creating CO2 - you do not get extra carbon molecules because they happen to be heaver than hydrogen.

quote:

Originally posted by APL:

Ahh! Could this be why pro-AGW prefer weight to molecular numbers.

Petrol and oil comprises of C5H12 to C18H38 in other words oil and petrol is (roughly) one part carbon to two parts hydrogen - that not 80-90% now is it.

Firstly, I'm doing this from first principles as I did earlier for the CO2 figures.
c5H12 has a molar mass of 5*12 + 12*1 = 72 so carbon is 60/72 or 83% by mass.
C18H38 has a molar mass of 18*12 + 38*1 = 254 so carbon is 216/254 or 85% by mass.
Secondly, you must be pretty ignorant to think that an H atom has the same mass as a C atom!

quote:

Hmmm... You assume coal is 100% carbon - no surprise there then 'sexing up' the facts again.

I hope those new to this game are beginning to see how exaggerated the pro-AGW claims are.

3 tons of C02 from 1 ton of coal would equate to about 82% carbon, assuming all carbon is consumed. That's not 100% is it?

quote:

Originally posted by APL:

Really - so where were you then as a 'true sceptic' putting right Steve_M's and realclimate's claims as to the amounts of carbon in fossil fuels.

Or is it you that holds the one-sided viewpoint you claim others to have?

What needed putting right? That you are ignorant of basic physical chemistry?

Just the facts, mate!

quote:

Originally posted by APL:

When does 44 = 44/12?

When does 273kg = 367kg?

You need to tell me where any of that comes from.

quote:

Originally posted by Son of Mulder:

I'm afraid you are wrong on this stuff. You have to work by atomic weight ie carbon =12 Hydrogen =1. Certainly basic O-level chemistry in my day.

so C5H12 is 60 carbon + 12 Hydrogen by weight so carbon = 60/72 ie 83% as the carbon and hydrogen numbers get bigger so the carbon % increases even more.

I'm a sceptic because I'm trying to find reasonable scientific holes in the AGW argument. I wish other sceptics would also instead of resorting to mudslinging tit-for-tat as they do a disservice to the process.

I try to raise observations I've made in the literature or from these posts that on the surface seem to contradict the "it's all down to anthropic CO2 hypothesis", whether science or presentational dirty tricks. But I try to do it within correct basic science to the best of my ability because it's the AGW argument that is potentially adversely influencing our society based on some sound science, some uncertainties and a hell of a lot of propaganda and projections that seem sometimes not to consider the falability of the methods used and other possible elements in the mix.

Well said, although I don't agree with all you say.

quote:

Originally posted by TrueSceptic:
Firstly, I'm doing this from first principles as I did earlier for the CO2 figures.
c5H12 has a molar mass of 5*12 + 12*1 = 72 so carbon is 60/72 or 83% by mass.
C18H38 has a molar mass of 18*12 + 38*1 = 254 so carbon is 216/254 or 85% by mass.
Secondly, you must be pretty ignorant to think that an H atom has the same mass as a C atom!

Explain how the weight of carbon has anything to do with carbon to CO2 creation - there's a clue in my last post.

quote:

Originally posted by TrueSceptic:
3 tons of C02 from 1 ton of coal would equate to about 82% carbon, assuming all carbon is consumed. That's not 100% is it?

Carbon content of coal is about 50% not 82%.

quote:

Originally posted by APL:

Explain how the weight of carbon has anything to do with carbon to CO2 creation - there's a clue in my last post.

The only clue is that your arrogance is in direct proportion to your ignorance.

Remember the question? It was

quote:

As another complete layman on the issue of climate change, I have a question about about CO2....if you oxidize a kilogram of carbon how much CO2 do you have? 3kg?
stuff about global warming often says how much space a ton of CO2 takes up, or whatever. But what does it take to make a ton of CO2 in the first place? a third of a ton of carbon? this is a question thats been bugging me for a while.

This has been explained in very simple terms from first principles. Each molecule of CO2 comprises 1 atom of C and 2 of O, so 1 tonne of CO2 comprises 273 kg of carbon, or if you prefer, 1 tonne of carbon will give you 3.66 tonnes of CO2.

How else would you like to express this? By volume? At std temp and pressure 1 tonne of CO2 gas occupies about 505 cu m.

quote:

Carbon content of coal is about 50% not 82%.

I'll take your word on that, although "coal" is very variable stuff. 50% would still give you about 1.83 tonnes of CO2 for each tonne of coal, assuming complete combustion.

In any case you need to apologise for claiming that anyone said that coal is 100% carbon.

What might be confusing is the way the atmosphere is analysed. Approximately the atmosphere consists as follows which I understand to be by weight.

N2=78%
O2=21%
CO2=0.35%
Others=0.65%

But one could choose to analyse it by molecule numbers.

N2=28 atomic units per molecule
O2=32 atomic units per molecule
CO2=44 atomic units per molecule

So molecule ratios N2:O2:CO2 would be
78/28:21/32:0.35/44

which gives an atmosphere of (ignoring the other gases)

N2=80.75%
O2=19.02%
CO2=0.23%

Now as it's molecules that hold the heat it would be more logical in my view to represent the atmosphere in these terms so CO2 would be 230 molecules per million molecules.

But as long as it's properly treated in the models it will make no difference which convention is used.

quote:

Originally posted by APL:

quote:

Originally posted by Steve_M:
Furthermore, petrol and oil is 80-90% carbon by mass. So a tonne of oil-based fuel gives you about 3 tonnes of carbon dioxide.

Ahh! Could this be why pro-AGW prefer weight to molecular numbers.

Petrol and oil comprises of C5H12 to C18H38 in other words oil and petrol is (roughly) one part carbon to two parts hydrogen - that not 80-90% now is it.

quote:

Originally posted by realprimate:
Yep. A ton of coal gives you 3 tons of CO2. There's centuries worth left and it's a real pollutant - particles, radioactivity and of course CO2.

Hmmm... You assume coal is 100% carbon - no surprise there then 'sexing up' the facts again.

I hope those new to this game are beginning to see how exaggerated the pro-AGW claims are.

APL – There’s no need to assume anything when it’s plain common facts.

There are many types of coal, including anthracite, bituminous, subbituminous, and lignite. Lignite has the lowest carbon content of coal, somewhere between 25 and 35 percent. Anthracite has the highest carbon content. The carbon content is anywhere between 86 and 98 percent (practically graphite).

According to Wikipedia
QUOTE
Anthracite coal is the highest of the metamorphic rank, in which the carbon content is between 92% and 98%.
UNQUOTE

Carbon dioxide (CO2) forms during coal combustion when one atom of carbon (C) unites with two atoms of oxygen (O) from the air. Because the atomic weight of carbon is 12 and that of oxygen is 16, the atomic weight of carbon dioxide is 44. So assuming complete combustion, 1 tonne of carbon combines with 2.667 tonnes of oxygen to produce 3.667 tonnes of carbon dioxide. (As it’s a ratio you can use any units – tons, pounds, kg, ounces… furlongs, cubits)

So the 3.667 tonnes is for 100% carbon. I stated 3 tons so “my” percentage is 3 tons divided by 3.667 tons multiplied by 100 which is 82%.

So “my coal” carbon ratio is somewhere below anthracite but well above lignite.

What proportion of coal is anthracite? Well there’s about 10 billion short tons in the US (a short ton is 2000lbs – a long ton is 2240lbs). That’s about 2% of the US coal reserves. As I said there’s centuries worth.

And thanks for the Freudian slip of calling me realclimate.

As far as I can see, the only reason for wanting to know all this guff is that "carbon footprints" are measured in tonnes of CO2 or tonnes of carbon. So if you know you use 1000 litres of petrol a year you can use the figures to help you calculate your carbon footprint. Other than that, there is no reason for knowing the information, so I don't quite know what APL is getting upset about - it is not an ideological argument.

Perhaps we could make it into one by measuring carbon footprints in microgrammes so that the numbers sound bigger.