CO2

Gurgle

Molecular chemistry is not my fortè, so throwing this out without much backing it....

CO2 is a molecular structure of one carbon atom (atomic number 6) and two oxygen atoms (atomic number 8).

By weight then CO2 is (16/22) 73% Oxygen, (6/22)27% Carbon.

A miscellaenous average living tree is approx 50% Carbon, 50% Water.
The carbon is absorbed from the air as the tree grows, in that the tree takes in atmospheric CO2 and releases O2.

For every tonne of living tree in the country, thats (0.5 x (100/27)) = ~1.8 tonnes of CO2 thats been absorbed from the atmosphere.

So is there a case to be made for the Carbon tax to be re-allocated in grants for micro-forestry projects, or am I off on a wild trip over the rainbow?

Jokesetal

Well over the rainbow....... and there ain't no pot of gold at the end of it either!
That's the basis of maintaining forestry as a form of carbon filtering or sequestering depending on your view AFAIK.


BTW: For the calculations you might want to use the atomic masses rather than the atomic numbers, but the values work out similarly!

Worztron

With grass, trees, etc. what is the ratio of oxygen to co2 in their lifetime? For example trees absorb co2 but all of that co2 is released if the tree is cut down – even if the tree is cut down, would it still have released more oxygen than co2 in its total lifetime?

Worztron

Worztron wrote: »

For example trees absorb co2 but all of that co2 is released if the tree is cut down – even if the tree is cut down, would it still have released more oxygen than co2 in its total lifetime?

The carbon dioxide isn't released when the tree is cut down. When carbon dioxide enters the plant, it is converted into other molecules, firstly glucose which then goes on to be used for other functions in the plant. However plants can release carbon dioxide during respiration, usually during the night. In general I think it's safe to say they produce far more oxygen than carbon dioxide.

If you burn the tree it will produce carbon dioxide though, is that what you mean?

Worztron

true-or-false wrote: »

The carbon dioxide isn't released when the tree is cut down. When carbon dioxide enters the plant, it is converted into other molecules, firstly glucose which then goes on to be used for other functions in the plant. However plants can release carbon dioxide during respiration, usually during the night. In general I think it's safe to say they produce far more oxygen than carbon dioxide.

If you burn the tree it will produce carbon dioxide though, is that what you mean?

Hi true-or-false. So if someone just cuts down a tree and uses it to build a house/furniture then the Co2 will not be released?

I'd like to know the ratio of oxygen to Co2 in an average tree lifetime (let's say the tree is chopped down to make a house).

And burning the tree will release all of the stored Co2 (but as you said not all of the Co2 is actually stored as it is converted into other molecules)?

Worztron

Worztron wrote: »

Hi true-or-false. So if someone just cuts down a tree and uses it to build a house/furniture then the Co2 will not be released?

No. There may be some trace amounts but certainly nothing noticeable.

I'd like to know the ratio of oxygen to Co2 in an average tree lifetime (let's say the tree is chopped down to make a house).

I'm in the middle of studying for exams, I just go on boards when I'm taking a break so I don't have time to crunch numbers, not sure I'd be able to anyway, sorry. Probably beyond my ability.

Here's what would probably be a helpful link:
http://www.coloradotrees.org/benefits.htm#10
Which quotes with a reference:

A single mature tree can absorb carbon dioxide at a rate of 48 lbs./year and release enough oxygen back into the atmosphere to support 2 human beings. (10)

And burning the tree will release all of the stored Co2 (but as you said not all of the Co2 is actually stored as it is converted into other molecules)?

Well as far as I know (don't know much about it to be honest) there isn't stored CO2. It's like humans, except with oxygen instead of CO2. We breathe it in, and yeah there'll always be some in our blood stream and travelling through our cells, but there's no space inside us where oxygen is kept on a long term basis. The CO2 is taken into the plant and used in photosynthesis to create glucose. The carbon dioxide doesn't exist anymore. It's been separated into carbon and oxygen. This carbon goes on to be used for energy and growth etc in the plant. So the wood itself is mainly carbon, but not carbon dioxide. The carbon dioxide is pretty much negligible if there at all. But when you burn it, the carbon in the wood reacts with oxygen in the atmosphere to create carbon dioxide. So the actual biomass of the plant is mainly carbon, and so by burning you're turning any of the carbon used for biomass into carbon dioxide.

I'm sure someone else around here would be able to give you better answers, or possibly on the biology forum. I had a quick (bear in mind not necessarily reliable) google and found one source claiming the plants are 45% carbon.

Worztron

Thank you true-or-false. A rough estimate would be fine. So the main point is that burning trees is a major no no for the environment. I'd love to sees trees being planted almost every where.

Capt'n Midnight

Carbon has an atomic number of 6 but an atomic weight of 12 (those pesky neutrons)
Oxygen has an atomic mass of 16 so CO2 weighs 44 gramms per mole.


mole

one mole of a gas occupies 22.4 Litres at 0 degrees C ( expands to 24.5 Litres at 25 degrees ) - you can use gas laws to work out gas volumes and stuff,


the main benefit of carbon neutral technologies is that they mean more fossil fuels aren't used

anyway one way to sequester carbon is to plough charcoal into the ground
another is to use ploughs to expose bed rock , as some types of rocks/minerals will form carbonates.

djpbarry

Worztron wrote: »

Hi true-or-false. So if someone just cuts down a tree and uses it to build a house/furniture then the Co2 will not be released?

Trees don’t contain carbon dioxide – they contain carbon that has been extracted from carbon dioxide in the atmosphere (through photosynthesis). More specifically, the carbon is stored in the form of wood, which is essentially a mass of cellulose fibres (cellulose is just a long chain of glucose molecules) held together by lignin. So carbon is extracted from air and locked into cellulose. Burning the wood breaks down the cellulose, releasing energy in the form of heat and also releasing the carbon (in the form of carbon dioxide).

Nolanger

0.053%

Capt'n Midnight

Nolanger wrote: »

0.053%

you are going to need a link to backup that claim for atmospheric CO2 levels since we are still less than 0.04%



Oh yeah in Oz there are peoples scheming to get carbon credits by killing one million camels / raising Kangaroos instead of cattle.


Anyway Earth may be headed into a mini Ice Age within a decade :pac:

Funk It

394.35 ppm according to CO2 Now (so yes, still less than 0.04%)
link here: http://co2now.org/Current-CO2/CO2-Now/

There is a lot of research being looked into co-firing and biomass energy power plants. As the converted energy is relative to the calorific value (heat energy produced through burning)

Table of calorific values: http://www.biofuelsb2b.com/useful_info.php?page=Typic

The people involved in biomass plants (wood burning for electrical energy) claim that it is "carbon neutral", as whatever trees are used, are replanted from source, thus restarting the process. I was initially sceptic about this until I learned that a fully grown tree only absorbs a small fraction of atmospheric CO2 as a younger growing tree does (I think I understood it as the amount of CO2 absorbed is proportional to the growth).

The part which I think has been overlooked in biomass plants claim to be "carbon neutral" is the sourcing of biomass, which for economic reasons is currently Canada and Norway/Sweden, whereby this transportation through use of barges, which run on fossil fuels are the main CO2 releasers in the process. Still, all in all, it is a better alternative to traditional fossil fuels. Currently, Irelands electricity is heavily reliant on imported gas afaik.

There are interesting new technologies with carbon capture and storage, as being introduced by SSE in their Longannet power station in Scotland. Again, being a little sceptical, I asked my fair share of questions to a man sent out from SSE, and besides lowering the plants efficiency, the technology does seem to make sense.

On the flip side, CO2 is proportional to plant growth, but in saying that, we are not going towards a healthy balance.

I hope that this is some help to this topic, and not too long winded!

amen

one mole of a gas occupies 22.4 Litres at 0 degrees C

when was the definition of a mole changed to volume at 0C (and why not K ) from 12g of pure C definition?

Capt'n Midnight

amen wrote: »

when was the definition of a mole changed to volume at 0C (and why not K ) from 12g of pure C definition?

A mole is just a number !

On team reckoned that the Avogadro constant, was 6.02214078(18)×10^23

So 12g of pure carbon would contain 6.022E23 carbon atoms (or one gram mole)

22.4L of ideal gas would contain 6.022E23 molecules of gas (at 0 degrees and normal atmospheric pressure - STP , standard temperature and pressure of course) , at 0K the volume of an ideal gas would of course be 0
some people use NTP , normal temperature and pressure, cos 20 degrees C is handier to work in than 0C

amen

I learned something new today.