Is burnt organic matter carbon?

Hello Sparky,

I doubt anyone will give a better answer than you have. This is the first time I have gone to the new questions list, you got there first again, but, you know your stuff!

Brilliant!

All organic matter contains carbon by definition. Showing cellulose is beside the point. We burn hydrocarbon fuels (the name says it all i.e. these compounds are made of two elements: hydrogen and carbon). The ratio of Hydrogen to carbon decreases as the chain length decreases, reaching the limit of 2:1 (H:C) for Polyethylene. Therefore the cleanest fuel (smallest CO2 (carbon) footprint) is the shortest hydrocarbon: methane or CH4, 2 moles of water for each mole of carbon dioxyde. 93%+ of Natural Gas is methane. Thus, the smartest and quickest way to reduce CO2 emissions from vehicles is to convert them to NGV's (Natural Gas Vehicles). The second, harder way, is to replace NG with electricity, for transport and heating, providing the electricity is generated via "green" methods: hydro, wind, nuclear, tidal, geothermal and solar are all good options in that order. Canada generates most of its electricity via hydro and France uses nuclear, 100% recycling method. The USA is far behind but catching up in Wind.

Buzneg, by definition, in chemistry field, organic means compounds of carbon and hydrogen, The wikipedia entry is a reader friendly start:

http://en.wikipedia.org/wiki/Organic_chemistry

As has been pointed out there are carbohydrates (sugars) in plant materials/foods, These first carmelize (why Toast tastes sweeter) then break down as water preaks off leaving carbon skeleton. Also small amounts of other elements are present in what remains as ash.

the black stuff is carbon.

milo

PS:

(In Green circles, Organic means without artificial chemical additives.

Though I'm thinking bone meal and blood meal,fish emulsion and the like, while acceptable Organic additives, are hardly "natural" in their occurrence.)

ty. do you know how to make carbon fiber out of this carbon? Also why doesn't this carbon burn, does it need more O2, higher heat, both?

No. I'm metallurgist, not Carbon fiber guy.

Carbon fiber burns, just not easily. Logs burn, just not easily. Diamonds burn too-again, not very easily. (Thats why they are coated with boric acid/alcohol mixture which is then burned off before being soldered into jewelry because of heat needed for higher carat solders. The deposited boric acid gets turned into a glassy layer on the stone that seals out oxygen.)

Carbon fiber burns. The japan carbon fiber association explains it 's difficult to do This way:

"As Carbon Fibers are solid-structured carbon and consequently are hard to be burned." -http://www.carbonfiber.gr.jp/english/tanso/06.html

Heres FAA statement:

In Carbon fiber composites, typically it is the resin that burns off first:

"While the vaporization of the resin will allow a flame to form in combustion, the remaining char and carbon can burn as a surface oxidation (smoldering) and even produce a carbon monoxide flame near the oxidizing surface. Typically, surface combustion needs a high temperature to be sustained, which is usually in excess of 500°C. "

"However, the carbon and resin char are now capable of oxidizing, and smoldering can ensue with the possibility of a carbon monoxide (CO) flame near the surface."

"The combustion efficiency is given by

χ=ΔhcΔhc,complete=20/26.5=0.75.

This suggests that the yield of soot and carbon monoxide is relatively high for flaming combustion. "

See 2.4-2.8 here: http://www.fire.tc.faa.gov/pdf/07-57.pdf

milo

In regards to buzneg's questions:

ty. do you know how to make carbon fiber out of this carbon? Also why doesn't this carbon burn, does it need more O2, higher heat, both?

Carbon Fiber is a crosslinked chain about 98-99% pure. The 2% additions are electrolytes and sizings to enable epoxy impregnation and handleability. It is manufactured by taking a spun precursor and heat treating it. Carbon Fiber, CF, is a bundle made out of 3K, 6K, 12K, 24K or 48K single strands. The precursor, PAN, to CF must be pure or void generation will occur during the heat treatment stages which will reduce the quality properties that characterize CF in epoxy such as TS, YM, ILSS ect.

Now your questions:

Synthesis of organics.....Sure. If one has ever taken this course this composed the last third of a year long learning process. Given ethanol and all the initiators/heat/UV/water at your disposal synthesize polyacrylonitrile, PAN.

Why doesn't this carbon burn? All elements/compounds have a characteristic melting point, boiling point, refractive index, flammability...... CF is stable - its crosslinked carbon. The last part of its heating process is in an inert atmosphere with temperatures of about 1200°C. The result is a pure, strong, electrically dissipative, chemically resistant, heat resistant product ready for impregnation for use in bridges, aerospace, sporting goods, automobiles, fuel cells the list is endless.

Good luck with your endeavor. Hook up with the Japanese if you want to know about the PAN. The Japanese have the knowledge to spin the purest form of PAN with the right amount/compound of oils and hence have the best CF in the industry.

Very simply the Black stuff on burnt wood is a mixture of carbon and less degraded carbon based compounds, and metal oxides. Ash from burning wood is not carbon, but silica and metal oxides like calcium oxide, sodium oxide, potassium oxide, magnesium oxide and iron oxides. Charcoal comes from burning wood in a oxygen poor environment, the balck stuff.

I believe an old term for this is carbon black, lamp black, or soot. I think it is unburned carbon due to too little oxygen in the burning process. It is what needs to be cleaned out of chimneys and stove pipes. There may be creosote also. It is an oily substance that holds the soot together and makes it stick to the stovepipes etc. I remember having army heating stoves sandblasted to get rid of the stuff.

I believe an old term for this is carbon black, lamp black, or soot.

This humble material, although known since ancient times, was only recently discovered to contains some very interesting materials: buckminsterfullerene and other allotropes of carbon.

So far the composition of the burn-tout stuff is concerned it may not be composed of only carbon. This is because most of the organic origin matters, although they are organic, contains other elements like S and N. So if the whole part of the stuff is burnt properly then the %age of these elements may not be high or at remarkable %age. But it is less found there remains no residual compounds of these elements.

So one cannot say that the burnt out stuff will surely be composed of only C ande H only. Altghough it is true that the majority are of them only, yet they are not the only component.

So far formation of the water in combustion is concerned there it always be so. But think if u can visualize few moles or kmoles of Watervapour.

So I hope u have your answer....

Ok so the black colour is from the carbon, but what is the white colour from, is that Sodium and Potasium? I notice hotter fires leave less of the black stuff, and more of the white stuff. People also say they make their own sodium hydroxide buy leaching ashes.

White stuff is usually high in K. One way of making KNO3 was to leach it from the ash of a wood fire, although I'm not sure how they purified it from there.

Numerous other minerals are present in smaller quantities, depending on the actual composition of the original timber.

Hotter fires usually burn the C off more completely, leaving less overall residue with a higher proportion of ash.

Once organic materials carbonise, they require quite a high temperature to burn. Carbon itself holds it's strength well at very high temperatures.

Ok so the black colour is from the carbon, but what is the white colour from, is that Sodium and Potasium? I notice hotter fires leave less of the black stuff, and more of the white stuff. People also say they make their own sodium hydroxide buy leaching ashes.

The white component of ash is mainly sodium oxide (Na₂O) and potassium oxide (K₂O). Trace amounts of oxides of other metals might be present too. If these oxides are mixed with water, they react to form hydroxides:

Na₂O + H₂O --> 2 NaOH

K₂O + H₂O --> 2 KOH

If either of these hydroxides is boiled with plant or animal fat (esters of long-chain carboxylic acids), "saponification" (ester hydrolysis) results, giving sodium salts of long-chain fatty acids -- one type of "detergent" or "soap"

NaOH + RCOOH --> RCOO^- Na⁺ + H₂O