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This article could use some work to make it more accessible to people who are not already familiar with the principles of thermodynamics and kinetic theory. I'm sure that schoolchildren and even adults who haven't had basic science education would find the explication of fundamental concepts here to be quite helpful. I've already drafted similar improvements for Phase (matter) (see my 10 July 2005 edits there), which are illustrative of what I have in mind. -- Beland 13:29, 10 July 2005 (UTC)
Think I made it about as simple/accessible as it's going to get; just wanted to mention here that I removed the technical template from here as well as the main article (there was one here, on the talk page, for some reason) - Straker 20:26, 18 October
Whilst this article is very well written and very fully instructed in the ideals of pressures and pressure gradients, it is missing something. I am thinking of the possibilty of a biological side to this topic. The ideas surrounding partial pressures of gases in the blood systems of animals allowing for transport and dissociation at tissues and the lungs. This is a relatively simple idea but one I think would greatly benefit this already good area of research. —Preceding unsigned comment added by 86.144.167.89 ( talk • contribs) April 26, 2006 (UTC)
In my opinion, this article needs quite a bit of editing to make it scientifically and technically sound. It also needs to be consistent throughout the article (for example, it uses different notation in different sections, notably the section on diving breating gases). The categories to which it is assigned really need to be more appropriate. For example, the list of categories needs to include Category:Chemical properties. Also, there is very little thermodynamics involved in the article as it now stands.
Someone who is really experienced in physical chemistry needs to do some major revisions. I will make some of the more obviously needed changes today .. and I may return later to do some re-writing. - mbeychok 17:23, 24 May 2006 (UTC)
J-A-R-G-O-N... make it easier to understand for the rest of us... -- toaster 22:16, 27 September 2006 (UTC)
why is henry's constant labeled as "k" instead of "H"? —Preceding unsigned comment added by 68.107.105.71 ( talk • contribs) November 6, 2006 (UTC)
The article text states:
This is true for ideal gases, but in general not true of liquids (nor does the ref given say it's true in liquids), and this fact is due to non-unity Henry's constants. Obviously, two different ideal gases at the same gas partial pressures have the same concentration, but they may well have (and generally will have) differing concentrations in a liquid in equilibrium with the gas. In such a case, if the liquid vanished, the relative gas concentrations would change. Liquids can pack more or less gas moles per volume than the gas above them. Cold water, for example, has about half as much oxygen per liter as the air above it. If the water vanished in an equilibrium mix of air and water, obviously the remaining air would have to accomodate a volume of gas with a lower oxygen volumetric content than air, and thus O2 partial pressure for the new mix would drop. I'll fix this in the text. S B H arris 22:45, 23 November 2006 (UTC)
In my opinion it is a very good article it helped me a ton with my science fair project and it is very useful in learning about lung capacity. —Preceding unsigned comment added by 66.119.143.249 ( talk • contribs) December 7, 2006
I thoroughly disagree with the proposed merger. There may be some redundancy between the two articles, but that is true of a great many Wikipedia articles. I see no great benefit or reason for this specific proposed merger. - mbeychok 19:22, 12 March 2007 (UTC)
The proposed merger tag was placed on Feb.22, 2007. After 4 months, there have been 3 comments disagreeing with the proposed merger and none that agree with it. I am therefore removing the tag. - mbeychok 18:45, 18 June 2007 (UTC)
In my opinion the subsection dealing with the partial pressure in breathing gas should be removed from this article as it is much too specific and has no real physical relevance to the concept of partial pressures. Opinions? —Preceding unsigned comment added by 220.101.176.63 ( talk) 10:53, 1 October 2008 (UTC)
The link to the "Ohio State Uni notes" ( http://undergrad-ed.chemistry.ohio-state.edu/chemapplets/GasLaws/DaltonsLaw.html) is no longer available. Maybe that someone could fix that (I don't know how to do it). User:87.65.146.187 10:41, 30 November 2008
Pressure is a physical quantity. Commonly for pressures, p is used as a symbol in physics. The capitol P stands for power... -- 95.89.0.171 ( talk) 21:13, 8 October 2009 (UTC)
I followed a link from there to this article and I'm having trouble understanding how the pressure change on oxygen causes the different training effect. Is this explained anywhere? DB ( talk) 17:47, 11 June 2011 (UTC)
The definition could be rephrased shorter by saying hypothetical pressure instead of the pressure the gas component would have if...--
86.125.152.170 (
talk)
10:35, 21 November 2012 (UTC)
Cite error: There are <ref>
tags on this page without content in them (see the
help page).
Also the definition includes the additivity of the partial pressures of components.
The definition implies an isothermal process .-- 79.119.217.178 ( talk) 10:48, 21 November 2012 (UTC)
The first sentence of the article seems to imply that the given definition of "partial pressure" applies only to ideal gases. I've removed the term "ideal" from the first sentence. — Preceding unsigned comment added by 142.157.149.8 ( talk) 22:31, 24 June 2013 (UTC)
The subject of this article is "Partial pressure":
Who decided that this article was to be an omnibus article covering so many diverse subjects which are covered by existing articles elsewhere in WP? mbeychok ( talk) 19:40, 12 January 2013 (UTC)
At present, this article employs a mixture of British and American English but should use just one variety per WP:ARTCON. Our guidance is at WP:ENGVAR and since there are no strong national ties for the topic, the style of English should be set by that used by the first major contributor, per WP:RETAIN. I believe the first major contribution that differentiated between en-gb and en-us was this edit, which used the British spelling 'metres'. I will therefore change the spellings throughout to use British English. -- RexxS ( talk) 16:51, 19 September 2014 (UTC)
The comment(s) below were originally left at Talk:Partial pressure/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
I have rated this article as being in Class A because it has all of the elements required for that class as described in the Assessment article. It is well written and has all of sections required by standard Wiki practice. However, I do feel it could still benefit from more improvement. It is of High importance to chemists and to chemical engineers. I cannot speak for its importance to Physicists. - mbeychok 05:45, 4 December 2006 (UTC) |
Last edited at 05:46, 4 December 2006 (UTC). Substituted at 02:19, 30 April 2016 (UTC)
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The article mentions Partial Pressure of Arterial Blood gasses in the medical section, but doesn't explain why this is particularly significant in the medical context as a useful measurement. Therefore the why tag has been added. 71.91.178.54 ( talk) 22:22, 20 October 2018 (UTC)
This articles reflects that the minimum partial pressure of oxygen ( O2 ) needed to sustain a human is 16KPa.
"The minimum safe lower limit for the partial pressures of oxygen in a gas mixture is 0.16 bars (16 kPa) absolute. Hypoxia and sudden unconsciousness becomes a problem with an oxygen partial pressure of less than 0.16 bar absolute."
This statement does not indicate a reference, but I feel it is patently false. At sea level on Earth the pressure is 14.7 lbs/in2 or 1 bar or 100 KPa. With the atmosphere made up of approximately 20% oxygen this yields a partial pressure of oxygen as 20 KPa or 200 mbars or .2 bar. Based on common atmospheric pressures for various altitudes I show the following:
alt in m alt in ft atmospheric pressure partial pressure of oxygen notes
0 0 100 KPa 20.0 KPa Sea level 1524 5000 84.3 KPa 16.2 KPa Denver, Colorado area (this is just above the lower limit sited in the page) 2134 7000 78.2 KPa 15.6 KPa This is where I have lived for 27 year (S of Elizabeth Colorado) 2591 8500 71.5 KPa 14.3 KPa This was my previous home I lived in for 6 years (On robinson hill road north west of Golden, Colorado) 3094 10,151 69.6 KPa 13.9 KPa City of Leadville, CO - spent 4 days on vacation here 3658 12,002 63.0 KPa 12.6 KPa City of Lhasa, Tibet 5099 16,724 60.1 KPa 12.0 KPa City of La Rinconada, Peru 6000 19,685 47.5 KPa 9.5 KPa Maximum human sustainability (Nat Geo, and several climber journals) 6096 20,000 46.6 KPa 9.32KPa Top of Mt. McKinley in Alaska. 8848 29,032 30.0 KPa 6.0 KPa Top of Mt. Everest.
I would think that the minimum partial pressure of oxygen would be about 9.5 +/- 0.5 for long term habitation and much lower for short amounts of time. I have hiked up several of Colorado's "14ers", mountain peaks above 14,000 ft elevation (4267 meters). While I did notice the lower air pressure I was able to hike up without oxygen carrying a backpack at over 60 years of age.
Given the cities cited above in Tibet and Peru and Colorado, all of which have a lower partial pressure of oxygen than the 16 KPa sited on the page. This figure cannot be true.
I have been unable to locate any citation showing a minimum partial pressure of oxygen for human life. The Apollo missions used much lower pressures, between 23 KPa and 34 KPa, but these were 100% oxygen. These were in the command module, LEM and EVA suits on the moon.
One supporting citation I found was by Dr. Michael J. Mulick, DO, Children’s Hospital Los Angeles, Los Angeles, CA. The excerpt is from an article in "Society for Pediatric Anesthesia" Volume 27, Number 3. "Climbing Mt. McKinley, one of the world’s seven tallest summits was one of the hardest things I have ever done. Mt. McKinley, known better by its native name Denali, meaning “The High One”, is the highest peak in North America at 20,322 feet.
My oxygen saturation on the summit was probably in the low 80's. The air temperature was well below zero with wind speeds up to 50 miles per hour. The only things I could focus on were to eat, drink, and keep moving. Climbers at high altitudes experience hypobaric hypoxia. Low barometric pressure causes the partial pressure of alveolar oxygen to be reduced at altitude as demonstrated in the alveolar gas equation:
PA02 = Fi02 * (Pb - PH2O) - (PaCO2/RQ)
On the summit of Denali, the barometric pressure is around 360 mm Hg which translates into a more than 50% reduction in available oxygen. This has profound effects on cognition, cardiopulmonary function, appetite, and sleep."
In the table above I show partial pressure of oxygen at sea level at 20 KPa and at the summit of McKinley at 9.32 KPa. This squares with his statement of "more then a 50% reduction".