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Alessandro Volta and methane
The wikiarticle about Alessandro Volta credits him with the discovery of methane; the wiki reports that he discovered methane during his studies of chemistry (1775-1776). If it's true, maybe it could be worth mentioning Volta also on the article about methane. — Preceding unsigned comment added by 151.20.46.182 (talk • contribs) 18:06, 21 January 2009 (UTC)
- Volta has since been added to this article. -- Beland (talk) 02:42, 21 June 2024 (UTC)
Offsetting methane calthrates and atmospheric presence
Direct absorption of carbon dioxide CO2 and methane CH4 gases from the environment and their conversion into nano solution and nano solnd pressure
(release date 06.01.2010) - REF 40
In this paper, results of processes will be introduced for tH4 gases direct from environment and their conversion into nano materials of here, concurrently within the processes of extraction of these gases in a simple reactor, we have managed to produce energy and oxygen.
http://www.keshefoundation.org/pdfs/CO2_paper.pdf
```` — Preceding unsigned comment added by 71.110.202.44 (talk) 01:57, 29 July 2012 (UTC)
- Wikipedia generally needs secondary sources, not so much research papers. -- Beland (talk) 02:43, 21 June 2024 (UTC)
Methane climate history
Could someone do a graphic showing the methane atmospheric climate history - I've read that ice cores can be used for it and have seen some articles related to it, but nothing with a graph showing concentration vs time (other than since the 1970s and such). LetterRip 22:34, 27 October 2007 (UTC)
- This has since been added to the article. -- Beland (talk) 02:43, 21 June 2024 (UTC)
methane asphyxiation
"Methane is an asphyxiant and may displace oxygen in a workplace atmosphere" , so it's perfectly safe to breathe methane "on the patio, in the car, or on the boat -- wherever good times are had" as long as it's not at work where employer liability make methane deadly ! ;) (I hope methane is actually heavier than air...)
- Well, where else (besides a laboratory, industrial site, etc) would one encounter large enough quantities of methane that could displace oxygen? 130.134.81.16 15:06, 11 July 2007 (UTC)
Methane and Nitrogen are potentially deadly to humans as an asphyxiant. Methane is readily available from community Natural Gas distribution pipelines, though it is now 'flavored' with H2S (Hydrogen Sulfide) to give early warning to potential gas leaks - natural gas is predominantly CH4 (Methane) by percentage. On a side note, the H2S used in the civilian distribution of Natural Gas is extremely low concentration, below 10-PPM...as H2S is extremely offensive to the olfactory senses...it is lethal above 20,000-PPM. REFERENCE MSDS SHEETS for 50-LD on H2S, while Methane MSDS can be read at: (http://www.vngas.com/pdf/g56.pdf)
Methane poisoning can include the effects of: blurred vision, CNS Depression and Rapid Heart Rate, predominantly as a function of asphyxia - though there is no risk of carcinogenic effects. http://www.wrongdiagnosis.com/c/chemical_poisoning_methane/symptoms.htm
Methane is also heavier than air, not lighter than air. (http://www.vngas.com/pdf/g56.pdf - page 3) —Preceding unsigned comment added by 72.147.141.172 (talk) 01:43, 11 July 2010 (UTC)
No, methane is lighter than air. (See various talk entries below.) The linked MSDS has moved, try this one: (http://avogadro.chem.iastate.edu/MSDS/methane.pdf) Toward the end you'll find Section 9: Physical and Chemical Properties. Note the SPECIFIC GRAVITY (Air = 1): 0.554. This means it is about half as heavy as air, and will not pool to form concentrations as heavier-than-air vapors might. DonWW (talk) 16:17, 27 June 2012 (UTC)
- The phrasing in the article has since been changed so as not to awkwardly refer to workplaces only. -- Beland (talk) 02:46, 21 June 2024 (UTC)
METHANE DISCHARGES STARTED IN ARCTIC OCEAN
The end of the world was announced but few noticed it. In a story about the dissappearing Ice in the North, was a note about the Alarming start of large scale Methane discharges.
Discharges that parrell those on the Permian/Triassic boundary.
It gives one pause. It may explain the puzzling silence of the heavens in a Universe which seems to always favor the start of life.
The natural evolution of life would never be 100 percent energy efficient on any world.
As life grows and becomes more complex it leaves an increasing mound of leftovers in the ground, inevitably, everytime.
When a form appears that is capable of inter planet communication it simultaneously achieves the ability to harvest and thrive on the leftovers which life has naturally gone through to produce its sentient form.
It is a "freebie" but with a terrible hidden cost that is realized to late. Life celebrates its sudden abundance of energy like a teenager on a motorcycle, and by the time it realizes the score, its too late.
If this be true, and I think it is, the one good thing we should do now is set up a beacon to transmit a warning to the Universe, in hopes that it will last long enough to be caught early enough in the brief 100 years of another world, and that that world will catch it in time, and survive, and progress.
Dan Pride DanPride (talk) 19:51, 28 August 2008 (UTC)
How is methane going to destroy the world? It lasts in the atmosphere for 8 years! hardly a period of time that people will not survive.
No what is the biggest danger in the world is idiots like you who think the end is here unless we all go back to a non industrilised society without oil etc —Preceding unsigned comment added by 121.73.44.28 (talk) 03:32, 28 February 2009 (UTC)
- atmospheric methane is overwhelmingly due to oceans releasing it naturally, has nothing to do with with industrialized society 67.70.118.33 (talk) 06:23, 25 December 2022 (UTC)
I smell Bullshit
A recent article (July 3, 2007) from the associated press blames methane accumulation in a manure *pit* for the asphyxiation deaths of 5 farmers, all related. Last I checked, this stuff is about half the weight of air, that is, it would have near half the lifting power of helium. There's just no reasonable way to imagine it could accumulate in a pit, and even in a covered pit if it asphyxiated anyone it would have had its effects at the opening of the pit rather than at the bottom of the pit, as the AP release said.
Whats really going on here? Some other toxic component of the pit gas perhaps? NOx or H2S increased by the runoff from the cattle feed located nearby?
The story as it changes is found at news.yahoo.com/s/ap/20070704/ap_on_re_us/methane_deaths
Zaphraud 18:07, 4 July 2007 (UTC) Manure pits can crust over, trapping methane production underneath the crust. When the pit is agitated prior to application to the land, all the entrapped methane is released at once. Yes, H2S can also be a risk, but if the media say it was methane , I suppose it was.50.65.22.103 (talk) 12:14, 9 December 2019 (UTC)
- H2S is the risk when working with manure pits not Methane
- Source: I’m a farmer Bogman bass (talk) 18:30, 29 January 2020 (UTC)
- Manure pits are not mentioned in this Wikipedia article. -- Beland (talk) 02:47, 21 June 2024 (UTC)
Goodland and Anhang analysis
The attribution of livestock's share of GHG simultaneously uses the 20-year GWP and the 100-year GWP for methane, with the former applied only to methane from livestock [page 14 of https://www.worldwatch.org/files/pdf/Livestock%20and%20Climate%20Change.pdf ] The attribution is thus meaningless and has been removed. OnceJolly (talk) 04:21, 15 July 2016 (UTC)
Check Scientific America
Im not sure if Im doing it correctly, but anyways, check Scientific America February 2007 pages 53 to 57, may help you about methane and global warming and the production of this gas by plants. — Preceding unsigned comment added by 24.51.239.30 (talk • contribs) 00:14, 19 March 2007 (UTC)
Error in formula
Shouldn't the number of CO2 molecules produced be 1? CH4 + 6O2 => C02 + 4H2O
- yup. fixing -- Tarquin 15:45 Jan 22, 2003 (UTC)
The equation is totally unbalanced. fixing. -Smack 06:09 20 Jun 2003 (UTC)
The correct reaction of the combustion of CH4 should be CH4(g) + 2O2(g) -> CO2(g) + 2H2O(l) —Preceding unsigned comment added by Reddyb2 (talk • contribs) 17:45, 2 October 2008 (UTC)
- Yup, it was fixed loooong ago (you're responding to a question from 2003:). Article presently says "CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) + 890 kJ/mole". DMacks (talk) 17:51, 2 October 2008 (UTC)
Source of statistics?
"80% of the world emissions are of human source." What is the source for this, and the other percentages? --SEWilco 20:25, 1 Sep 2003 (UTC)
USDOE says: "Anthropogenic sources are estimated to be 60 percent of total methane emissions" - http://www.eia.doe.gov/oiaf/1605/ggrpt/emission.html They reference: "Intergovernmental Panel on Climate Change, Climate Change 2001: The Scientific Basis (Cambridge, UK: Cambridge University Press, 2001), p. 248"
A huge amount of methane is created from bacteria in padi fields in china and other asian countries 18:35, 11 December 2006 (UTC) [Luppers]
Global warming potential
The GWP of methane is reported as 21, 22 and 29 on various pages - "Methane" and "global warming potential" - is this an inaccuracy or is there some doubt over what the figure actually is? Or is it a variable depending on other factors? --Bug
- There are 2 factors here. The first is the timescale which you calculate the GWP for - methane is rremoved from the atmosphere with a lifetime of about 9 years i.e. quicker than CO2 so it becomes relatively less important over longer periods of time. TAR[1] gives 62, 23, 7 for 20 years 100 years and 500 years. The second source of confusion is that there is some uncertainty in the removal rate of methane. It cannot be measured directly but has to be modelled or deduced from other observations. This leads to the uncertainty. I recomend:
- A GWP is meaningless without indicating the timescale for which it was calculated
- All quoted GWP figures should be sourced.
- --NHSavage 08:54, 18 January 2006 (UTC)
- Now made necessary changes to the article.--NHSavage 22:39, 18 January 2006 (UTC)
- There are 2 factors here. The first is the timescale which you calculate the GWP for - methane is rremoved from the atmosphere with a lifetime of about 9 years i.e. quicker than CO2 so it becomes relatively less important over longer periods of time. TAR[1] gives 62, 23, 7 for 20 years 100 years and 500 years. The second source of confusion is that there is some uncertainty in the removal rate of methane. It cannot be measured directly but has to be modelled or deduced from other observations. This leads to the uncertainty. I recomend:
- Methane is a greenhouse gas with a global warming potential of 22. What does this sentence mean ? --Taw
Global warming potential is a measure of how much global warming a gas causes, relative to carbon dioxide. Unfortunately I don't understand all the technical details, but I think it means that a given mass of methane causes 22 times as much global warming as the same mass of carbon dioxide. -- SJK
What is measured ? How much warming is caused by the same volume of gase, the same weight of gas or by yearly emmision of gas ? --Taw
- The same mass.--NHSavage 22:39, 18 January 2006 (UTC)
I believe it is how much a given mass of the gas warms the earth in a given period, compared to how much the same mass of CO2 warms the earth in the same period, but you'd have to check. -- SJK
If it's a real concept, we need an article: global warming potential.
That article exists. Issue resolved. - SEWilco
Global warming potential 2
It says methane is eight times stronger than carbon dioxide as a greenhouse gas in the first section (Sources of methane) then says it's twenty times stronger in the "Methane on Earth" section....which is it? -- djohnsto77
- This appears to have since been fixed. -- Beland (talk) 03:09, 21 June 2024 (UTC)
Methane in planetary science
May I offer a suggestion: One of the most fascinating appearances of methane (especially since the new results of the Huygens probe on Titan) is in the planetary sciences. Some mention would be nice. See http://www.newscientist.com/channel/space/cassini-huygens/dn6910 for an interesting example. Archie Paulson 19:57, 21 Jan 2005 (UTC)
- Discussion of methane on other solar system bodies, including Titan, has since been added. -- Beland (talk) 03:12, 21 June 2024 (UTC)
Prognostications on first day when Titan methane is burned on Earth
Would this be an appropriate forum to speculate on when the first methane harvested from Titan will be burned on Earth?
- Probably not here. And it's easier to use agriculture or fissionables to make methane than ship that light stuff. (SEWilco 15:54, 15 Mar 2005 (UTC))
Methane's global warming potential
Is methane's global warming potential 21 or 23? I am unsure about this could someone help me?
- According to IPCC Third Assessment Report it is 23. This is a complicated calculation as it must account for how quickly emissions are removed from the atmosphere which is a complex process (the second assesment gave the figure of 21 but as this is based on older data the IPCC TAR figure of 23 should be used). Note also that this is the figure for a 100 year period. If you are interested in shorter or long times the number is different.--NHSavage 22:42, 18 January 2006 (UTC)
density
Is methane denser or less dense than air? I realize it should be easy to figure this out from the molecular formula and the density of air, but if it's less dense than air (which I think it is) then that's an interesting fact that might be good to add.
- Less dense. About 55% the density of air. I added mention of its being lighter than air to the "...on Earth" section. (SEWilco 15:42, 4 October 2005 (UTC))
Thanks!
The density cited (0.717) sems to be the densit at 273K. The density at 298K is 0.656. (Westy32 (talk) 12:08, 1 April 2010 (UTC))
- As a quick fix, I just added temperature to the infobox. Materialscientist (talk) 09:34, 2 April 2010 (UTC)
- On 26 Sep 2020 @Mina.farhang: changed density to 0.717 kg/cubic meter at 0C, from 0.717 g/liter. Figure is 0.554 kg/cubic meter in https://www.aqua-calc.com/calculate/volume-to-weight/substance/methane-coma-and-blank-gas I will change to match that source unless someone has better source? Numbersinstitute (talk) 22:08, 29 September 2020 (UTC)
Aqua-calc seems to be a minority view. I found the following sources, and the most reliable seems to be UNFCCC, so I will cite that in the article. I leave the others here, since they do vary, to show the consensus in the field. The last item, NIST is interesting in saying how they calculated their number. It's useless to cite since they don't give temperature or pressure, but the value implies an average temperature of -7C. The table shows units reported by each source, and converted to kg/cubic meter, and converted to 0C (by ratio of degrees K) to show the consistency. Table also shows kg per standard cubic foot (60F, 1atm) as used for US natural gas industry. Numbersinstitute (talk) 20:11, 2 October 2020 (UTC)
Methane as a fuel
Can methane be used as a Substitute for fossil fuels as a major source of vehicle energy? —The preceding unsigned comment was added by STEVE (talk • contribs) 04:52, 7 October 2005 (UTC)
- Much of the widely used fuel natural gas is methane. Natural gas is harvested from underground deposits and contains a variety of hydrocarbons and other gases, much of it being methane. (SEWilco 13:24, 7 October 2005 (UTC))
- No because methane is a fossil fuel. Qemist (talk) 22:28, 30 October 2009 (UTC)
Methane entry needs a complete overhall
The information on methane and its presentation is not up to the standard of other articles in Wikipedia.
Much of it is simply unintelligible (perhaps written by people who speak English as a second language?). There are many statements that are, at best, misleading, and at worst complete nonsense, eg: "Methane acts on organic rich shales and produces a minor contribution (1-3%) to form petroleum with true biomarkers as hopanoids and others insaturated hydrocarbons (n-alkenes). Methane interacts with peats, forming coal and bearing mercury, nickel, arsenic,cadmium, selenium, vanadium, uranium and other toxic metals."
Someone with a good knowledge of organic geochemistry AND the English language please should rewrite the entire entry. —The preceding unsigned comment was added by 82.83.210.13 (talk • contribs) .
- I will post this at Wikipedia talk:WikiProject Chemicals. Physchim62 (talk) 11:22, 20 November 2005 (UTC)
(copied following from Wikipedia talk:WikiProject Chemicals)--NHSavage 23:18, 18 January 2006 (UTC)
- I agree. That article is a real mess. However, the article on methane in the German Wikipedia (http://de.wikipedia.org/wiki/Methan) seem to me to be very good (based on my rusty German). That would probably be a good place to start in order to get the English version up to a higher standard. Edgar181 19:05, 21 November 2005 (UTC)
Proposed revamped structure
I suggest that the first thing to do on this article is a major reorganisation as followa:
- Properties
- Reactions of methane
- Uses of methane
- Sources of methane
- Units of measurement
- Methane in the Earth's Atmosphere
- Emissions
- Biological emissions
- Industrial emissions
- Atmospheric chemistry and concentrations
- Emissions
- Extraterrestrial Methane
- Miscelaneous
- Methane in heraldry
- See also
- References
- External links
Any comments?--NHSavage 23:11, 18 January 2006 (UTC)
New revision.--NHSavage 19:37, 19 January 2006 (UTC)
I like this suggested organization. A few possible alterations:
- separate industrial use of methane (as a chemical feedstock) from its use as a fossil fuel into different sections
- the "Sources of methane" section could focus on introduction of methane into the atmosphere and a separate section on geological sources could focus on natural deposits from which methane is "mined" for industrial and fuel use
- the section on heraldry is trivia and can be eliminated -- Edgar181 19:55, 19 January 2006 (UTC)
- I am now rewriting in the new structure for draft see: my sandbox--NHSavage 17:09, 21 January 2006 (UTC)
- Done. The article IMHO has a better structure and some of the worst elements of the old article are gone. It needs a lot more work but these are now more neatly divided up into sub sections. --NHSavage 18:52, 21 January 2006 (UTC)
Living plant sources
According to [2] it is 10-30%
- Although the scientists have some first indications, it is still unclear what processes are responsible for the formation of methane in plants. The researchers from Heidelberg assume that there is an unknown, hidden reaction mechanism, which current knowledge about plants cannot explain - in other words, a new area of research for biochemistry and plant physiology.
- In terms of total amount of production worldwide, the scientists' first guesses are between 60 and 240 million tonnes of methane per year. That means that about 10 to 30 percent of present annual methane production comes from plants. The largest portion of that - about two-thirds - originates from tropical areas, because that is where the most biomass is located. The evidence of direct methane emissions from plants also explains the unexpectedly high methane concentrations over tropical forests, measured only recently via satellite by a research group from the University of Heidelberg.
- But why would such a seemingly obvious discovery only come about now, 20 years after hundreds of scientists around the globe started investigating the global methane cycle? "Methane could not really be created that way," says Dr. Frank Keppler. "Until now all the textbooks have said that biogenic methane can only be produced in the absence of oxygen. For that simple reason, nobody looked closely at this."--Paleorthid 03:12, 12 January 2006 (UTC)
And according to [3] it is up to 1/3 based on the same source, but not sure how they figured it quite that high.
- The world of climate change science and policy has been rocked by the discovery that plants produce up to one-third of the second most important greenhouse gas.
- The findings are published in Nature today (12 January) by a team led by Frank Keppler from the Max-Planck Institute in Germany.--Paleorthid 17:20, 12 January 2006 (UTC)
Quote for "up to 1/3" [4]--Paleorthid 05:18, 14 January 2006 (UTC)
- Please see the discussion of this on Talk:Global_warming#Methane. I will try and get a recent review of methane sources and put it on here. One paper a) might be wrong b) might have made incorrect assumptions when it scaled up from plant to ecosystem to global emissions. The dust needs to settle a bit (which is not to say this is not good science - it is an excellent example of how the scientific consensus on a subject can be challenged).--NHSavage 08:22, 18 January 2006 (UTC)
- Note that I have now added another reference in which the orginal Keppler et al paper is challenged. This is a very contentious issue at present.--NHSavage 18:38, 23 May 2007 (UTC)
- Please see the discussion of this on Talk:Global_warming#Methane. I will try and get a recent review of methane sources and put it on here. One paper a) might be wrong b) might have made incorrect assumptions when it scaled up from plant to ecosystem to global emissions. The dust needs to settle a bit (which is not to say this is not good science - it is an excellent example of how the scientific consensus on a subject can be challenged).--NHSavage 08:22, 18 January 2006 (UTC)
Clarification requested
What does "a Global warming potential of 23 over a 100 year period" mean? -- Beland 02:28, 3 March 2006 (UTC)
- Added a claification. For more details see Global warming potential.--NHSavage 08:34, 3 March 2006 (UTC)
- Belated thanks! -- Beland (talk) 01:23, 18 June 2024 (UTC)
Sudden release from methane clathrates
- Woudn't the methane burn, thus
- Producing short term heating leading to catastrophic methane release
- Producing up to 100 times the current levels of C02 (and a similar amount of H20 raising sea level 10 cm) and consuming 20% of the oxygen in the atmosphere
Assumptions Mass of atmos 10^21 g 21% * 21% oxgygen = 2*10^20 g * .04% CO2 = 4*10^17 g Mass of clathrates "ten million million tons" ~ 10^19 g The area of the World Ocean is 361 million square kilometers ~ 4*10^14 m^2 = 4*10^18 cm^2 Methane reaction CH4 + 2(O2)=> 2(H20) + CO2 16g + 64g => 36g + 44g
Rich Farmbrough 22:58 21 June 2006 (GMT).
- Even allowing the unlikely event that all the methane would be released at once, the lower flammability limit of methane in air is around 5%, so if the released methane was 1% of the atmosphere, it would not form a flammable mixture. Shimmin 03:32, 22 June 2006 (UTC)
Moved here from science ref desk
WIKI "Methane Gas" article is DANGEROUSLY UN-Scientific & MISLEADING
This is a VERY serious discrepancy in your article about METHANE GAS because:
- YOUR ARTICLE SAYS THAT METHANE GAS IS NOT TOXIC -
- HOWEVER, THAT SAME ARTICLE SAYS THAT METHANE GAS IS AN ASPHYXIANT.... WHICH CAN CAUSE A PERSON TO NOT BREATH NORMALLY, CAUSE UNCONSCIOUSNESS, BRAIN DAMAGE AND DEATH.
- WOULDN'T THAT BE TOXIC TO LIVING ORGANISMS?
- Please see excerpts from article below:
Methane is not toxic by any route. ....... Methane is an asphyxiant and may displace oxygen in a workplace atmosphere. Asphyxia may result if the oxygen concentration is reduced to below 18% by displacement. The concentrations at which flammable or explosive mixtures form are much lower than the concentration at which asphyxiation risk is significant. When structures are built on or near landfills, methane off-gas can penetrate the building interior and expose occupants to significant levels of methane. Some buildings have specially engineered recovery systems below their basements, to actively capture such fugitive off-gas and vent it away from the building. An example of this type of system is in the Dakin building, Brisbane, California. [edit] Reactions of methane The reactions with methane are: combustion, hydrogen activation, and halogen reaction.
Asphyxia (from Greek a-, "without" and sphuxis, "pulse, heartbeat") is a condition of severely deficient supply of oxygen to the body that arises from being unable to breathe normally. Asphyxia causes generalized hypoxia, which primarily affects the tissues and organs most sensitive to hypoxia first, such as the brain, hence resulting in cerebral hypoxia. Asphyxia is usually characterized by air hunger but this is not always the case; the urge to breathe is triggered by rising carbon dioxide levels in the blood rather than diminishing oxygen levels. Sometimes there is not enough carbon dioxide to cause air hunger, and victims become hypoxic without knowing it. In any case, the absence of effective remedial action will very rapidly lead to unconsciousness, brain damage and death.[1] The constriction of the arteries and/or veins in the neck, such as in certain types of strangulations, do not cause asphyxia but rather direct cerebral hypoxia. Asphyxiation or suffocation refer to the process of asphyxia, where the body becomes increasingly hypoxic.
Toxicity (from Greek τοξικότητα – poisonousness) is a measure to the degree to which something is toxic or poisonous. The study of poisons is known as toxicology. Toxicity can refer to the effect on a whole organism, such as a human or a bacterium or a plant, or to a substructure, such as the liver. By extension, the word may be metaphorically used to describe toxic effects on larger and more complex groups, such as the family unit or "society at large". In the science of toxicology, the subject of such study is the effect of an external substance or condition and its deleterious effects on living things:organisms, organ systems, individual organs, tissues, cells, subcellular units. A central concept of toxicology is that effects are dose-dependent; even water is toxic to a human in large enough doses, whereas for even a very toxic substance such as snake venom there is a dose for which there is no toxic effect detectable.
Thank you. —Preceding unsigned comment added by 67.113.165.130 (talk) , at WP:RD/S
- (5th edit conflict)Please don't overreact like this. Look, it is simple. Methane is not toxic, but if you ONLY breathe methane, than you die. Humans need OXYGEN not METHANE to live. Also, please sign your posts with a —~~~~ — [Mac Davis] (talk)
- Thanks for pointing that out. Would you be able to change the article so it was correct?--Light current 16:07, 21 August 2006 (UTC)
- A cushion can be non-toxic, but it could be possible to smother someone to death with it. Toxicity has nothing to do with asphyxiation, IMHO. --Kjoonlee 16:08, 21 August 2006 (UTC)
- If you want to discuss articles, the best place would be Talk:Methane. --Kjoonlee 16:08, 21 August 2006 (UTC)
- Yeah. Good point. Should this post be moved there. I thnik so!--Light current 16:12, 21 August 2006 (UTC)
- Toxicity and asphyxiant are different things, methane is not toxic, breathing methane mixed with a sufficient amount of oxygen does not harm anybody significantly, and one can do that for quite a long time. It is an asphyxiant, indeed, but an axphyxiant is not a toxin. As the saying goes, 'drowning: it is not the water that kills, its the lack of air'. I do not see why the document should be changed. --Dirk Beetstra T C 16:49, 21 August 2006 (UTC)
- I think what we're talking about here is the difference between a lay and a technical understanding of the word "toxic". I would say that we should link to the article on toxicity here but I see that is already the case. I think the article is pretty clear on the dangers of methane as it is and find it ironic that the person who is accusing it of being "un-scientific" and "misleading" is the one who doesn't know the actual definition of the word toxic. It basically means "poisonous", not "harmful" or "deadly". Big difference there—lots of things are harmful or deadly that are not poisonous (like falling out of a window). --Fastfission 19:38, 21 August 2006 (UTC)
- Quick sanity check for our anonymous guest: Is nitrogen toxic? It makes up 70% of the air we breathe, but if you breathe pure nitrogen, you'll suffocate. At the accelerator where I work we use lots of liquid nitrogen, and if you let too much boil off in a confined space you'll start to get light-headed, because it displaces oxygen. —Keenan Pepper 06:11, 22 August 2006 (UTC)
- Just wondering .. an atmosphere of 100% oxygen .. would thát be toxic? After all, then you are breathing in a gas which consists for almost 100% out of radicals .. or worse .. a diradical! And liquid oxygen, can't be toxic either, can it .. --Dirk Beetstra T C 06:30, 22 August 2006 (UTC)
- No, it's not toxic; read all the discussions above. It would still be deadly, however, because you need carbon dioxide to trigger your breathing reflexes, AFAIK. --Kjoonlee 12:37, 22 August 2006 (UTC)
- The early space missions used 100% oxygen atmospheres - until both the U.S. and Russia experienced fires in the cabin. Of course, they weren't talking to each other and had to both have deadly accidents before its use was abandoned. Rmhermen 19:02, 22 August 2006 (UTC)
- Yeah, you can definitely breathe pure oxygen as long as the pressure isn't too high (see Oxygen toxicity). That stuff about needing carbon dioxide doesn't make sense, because you produce CO2 all the time. —Keenan Pepper 21:05, 22 August 2006 (UTC)
- The early space missions used 100% oxygen atmospheres - until both the U.S. and Russia experienced fires in the cabin. Of course, they weren't talking to each other and had to both have deadly accidents before its use was abandoned. Rmhermen 19:02, 22 August 2006 (UTC)
- No, it's not toxic; read all the discussions above. It would still be deadly, however, because you need carbon dioxide to trigger your breathing reflexes, AFAIK. --Kjoonlee 12:37, 22 August 2006 (UTC)
Water toxicity move to Science ref desk--Light current 20:57, 22 August 2006 (UTC)
The CO2 driven breathing reflex is due to the CO2 concentration in your own body, which generates its own CO2. Thus breathing an atmosphere entirely lacking in CO2 would not be a problem in that regard. I am however puzzled by the statement that if oxygen falls below 18.5%, asphyxia results. The normal concentration of oxygen is 21% (by volume) or 23% (by weight) so this seems a rather small diminution, given that people can survive easily enough at altitudes where the atmospheric pressure is half normal, and I thought that the key issue was that for breathing to keep you alive you need the partial pressure of O2 in the air to be higher than the equilibrium partial pressure over a haemoglobin solution, thus the benefit of breathing pure oxygen at low pressure.
If air is displaced purely by CO2 then it can act as an asphyxiant at relatively moderate (5-8% I think) concentrations because it messes up the equillibrium with hemoglobin. If it is displaced by a different gas then you can breathe O2 at much lower percentages. The 19.5% quotation is of I think OSHA health regulations. —Preceding unsigned comment added by 12.232.225.131 (talk) 04:22, 15 July 2010 (UTC)
Methane amu of 16.04 or 16.01? The story so far
The saga to date: from the talk page of 68.42.137.160 (talk · contribs)
A link to the edit I have reverted can be found here: link. If you believe this edit should not have been reverted, please contact me. See this link which confirms original text: 16.04 Paleorthid 14:53, 9 September 2006 (UTC)
You know what, you're right. I apologize. Despite what I did wrong, I do have a suggestion that will help you. You can round 1.008 to 1.01. Plus, the hydrogen atom has 1 proton and 1 electron. That electron can be worth 1/100 of an atomic mass. So 1 hydrogen atom can have an atomic mass of 1.01. So that means methane can have an atomic mass of 16.05.—Preceding unsigned comment added by 68.42.137.160 (talk)
I don't have the Merck index. It's possible, however unlikely that it says what I said. —Preceding unsigned comment added by 68.42.137.160 (talk)
I'm sorry for vandalizing. I was just thinking methane had an atomic mass of 16.01, because I was thinking hydrogen had an atomic mass of 1.00. Anthony P.
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After this extensive discussion I think it is clear we are being trolled. Is there an Admin around to deal with this? David D. (Talk) 20:22, 13 September 2006 (UTC)
- At best, we have a good-faith editor who is stubbornly failing to learn what we're all trying to teach him and who doesn't understand the WP collective-editorship system. It appears that:
- 16.04 is the calculated answer when one does not make mathematical mistakes (round-off errors) or mis-understand what atomic mass means in this context
- 16.04 is what Aldrich lists
- there's no basis remaining for any other value
So 16.04 it is. DMacks 20:42, 13 September 2006 (UTC)
- silly discussion see Aldrich with 4*1.0079+12.011 (its all about isotopic distribution) you get to 16.043, please ban the troll V8rik 21:39, 13 September 2006 (UTC)