Talk:Gas

From Wikipedia, the free encyclopedia

Gas is included in the 2007 Wikipedia for Schools, or is a candidate for inclusion in future versions. Please maintain high quality standards, and make an extra effort to include free images, because non-free images cannot be used on the CDs.
Gas was a good article nominee, but did not meet the good article criteria at the time. There are suggestions below for improving the article. Once these are addressed, the article can be renominated. Editors may also seek a reassessment of the decision if they believe there was a mistake.

Reviewed version: February 27, 2008
Peer review Gas has had a peer review by Wikipedia editors which is now archived. It may contain ideas you can use to improve this article.
This article is within the scope of the following WikiProjects:
To-do list for Gas: edit · history · watch · refresh

Here are some tasks you can do:
  • Wikify:
    • Bulleted list of simplified gas models. Make sure to maintain clarity of the list of assumptions made for each model. If the message is lost that the models are actually models and not reality, then the purpose is lost.
    • Historical Synthesis section
    • Cleanup:
    • Random grammatical errors that haven't been found.
    • Expand:
    • Lead Section to avoid confusion with plasma. See: Wikipedia:Lead section.
    • Summary of Kinetic Theory under the Microscopic section.

Contents

[edit] Unsorted "Talk"

Uh, isn't 'gel' another state of matter?

Removed the following: "(Incidentally, these phases correspond to the four basic elements distinguished in Antiquity: earth (solid), water (liquid), air (gas) and fire (plasma))." That's just silly. It's incredibly anachronistic (do you honestly think the ancient Greek had knowledge of plasma?) and it's not even technically correct - the four elements are made up of four properties - hot, wet, dry and cold, which arguably correspond far more closely to the states of matter anyway.

I think there should be a link to four elements somewhere, either in this article or in the disambig page. Something like "Gas is one of the four classical elements". --Stevage 14:21, 3 December 2005 (UTC)
But it's not one of the four classical elements! (unsigned, anon)
That's...a good point. Stevage 21:02, 4 December 2005 (UTC)


Can you tell me about why the gas prizes are so high?

See Gasoline - JM 12:50, 25 August 2005 (UTC)

[edit] More about use?

Shouldn't there be a section about the use of gas here, the growing importance of gas (for instance for heating etc.) and domestic uses? --Vikingstad 23:45, 21 November 2005 (UTC)

Ah, nevermind, I suppose the See Also link to Natural Gas is good enough... --Vikingstad 23:50, 21 November 2005 (UTC)

[edit] water vapor

1st para: "which will then boil or evaporate to become a gas (e.g. water vapor)" Surely water vapour is not a gas, but particles of water suspended in air? Water in its gaseous state is Steam, an invisible gas which can only be produced under presure.

Water vapor is the gaseous form, usually used for conditions below the boiling point. Stream is water vapor at or above the boiling point. At least that has been my understanding. Thanks, Vsmith 13:12, 9 January 2006 (UTC)
The definition of gas versus vapour that I'm familiar with is that if a substance in a certain condition is above it's critical point then it's a gas, otherwise it's a vapour. Hence steam coming out a kettle is vapour, but steam at the top end of a supercritical steam turbine is a gas. Haven't got time to have a proper look around but the page on critical pressures for gas will no doubt cover this. 131.111.216.249 21:23, 2 May 2007 (UTC)

[edit] Definition of gas

The article lacks a more precise definition of gas (i.e. how can I know if a substance is in a gas state?). The article cites many properties of gases, but does not say which of them (if any of them) completely characterizes a gas. I don't know if there is a generally accepted definition, in case there is more than one we could write a discussion paragraph comparing them. I've seem somewhere that gas is a state where matter occupies any container. That is a very simplistic one (and formally wrong, I believe), does someone know a more technical definition? I like the fire article, maybe we could use it as a parameter for quality. Rend 01:06, 20 April 2006 (UTC)

[edit] No intermolecular forces?

In the gas phase, the atoms or molecules constituting the matter basically move independently, with no forces keeping them together or pushing them apart.

I thought there still are intermolecular forces, but that these forces can be neglected in the gas phase, especially when the gas is considered as an ideal gas.

[edit] Why are the gas prices so high?

Because Uncle Sam hasn't really done much in the search of alternative energy sources. How about solar

power? Dont hear much about that, and the sun is on a stringent and dependant time schedule! Very dependable! Something is fishy. Forget the other countrys, center on America. Wait a second.... We are in debt and most our investors are foreigners... There is nothing we can do to become dependant because We would ween ourselves off the other countrys that are investing in this country. We will, as a group, never become independant with our own system of fuel... The saudis, or whoever owns the oil, own us.

How do I know this? Because many years ago, I devised a simple soulution for a diverse system of

ecomical fuel supply partly involving the wind and sunlight. Shortly there after, some men in black came to my door and destroyed everything! My complex blueprints for a stronger America went down the

drain. 
The conspiracy involves very rich people investing in other countrys. Mostly polititians, the people who

alledgedly work for the Americans in this country. The foreigners are supposed to be second to us. Maybe we just aren't vocalizing our concerns loud enough. The men in black told me, the real solution is easy, start riding a bicycle. I was so mad.

[edit] Common type of gases

Would flatus be considered a trace gas, or what? Or should it have its own listing under "types?" --Jay (Histrion) (talk • contribs) 20:05, 28 December 2006 (UTC)

[edit] Plural

Should it be 'gases', or 'gasses'? Theoretically, it should be the latter, since 'gases' should be pronounced 'gai-ses'. But I don't know. That should be in there somewhere, right? -Uagehry456|Talk 20:27, 12 April 2007 (UTC)

[edit] how many gases?

It seems that there must be a finite number of gases. For example at say atmospheric pressure and room temperature hexane is not a gas but methane is. So there are maybe 50 hydrocarbon type gases (including halogenated hydrocarbons, unsaturated ones etc.), and so on for elements such as oxygen etc.

So is there a list somewhere of all the gases which exist?

Just a dabbler 10:09, 30 May 2007 (UTC)

[edit] Gas does not "expand to fill whatever space it can"

If you spray CO2 from a fire extinguisher, does it fly out in all directions to fill the entire room? No, it pours out, lands on the floor, and forms pools. Gas only expands to fill whatever space it can if that space is a vacuum. [1] — BRIAN0918 • 2007-06-08 14:51Z

Your observation is correct, but you are mistaken in your conclusion. A gas will expand to uniformly distribute itself in any container in the absense of any external forces acting on the gas. In the case of your observation, the external force is gravity. It does not have to be a vacuum for the gas to diffuse. Consider opening a small cannister filled with gasous nitrogen. Its density is extremely close to that of air, and so the force of gravity can be ignored since the nitorgen will be neutrally buoyant. In this case the nitorgen gas will expand until it is homogenously mixed with the rest of the air. CoolMike 21:28, 1 August 2007 (UTC)

The forces acting on gas particles are pretty complicated if you're gonna get all nit-picky about it. i guess if someone had some time, they could add some info to this article or link to another one. One thing about the Fire Extinguisher example is that different kinds of gasses(or gases) have different properties. And also, CO2 wil eventually mix into the atmosphere just like Nitro will, just might take a little bit longer for CO2 to do it. —Preceding unsigned comment added by ROBO HEN5000 (talk • contribs) 20:54, 24 September 2007 (UTC)

[edit] WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 09:52, 10 November 2007 (UTC)

[edit] Article Rewrite

Hi! I am currently re-writing this article so it makes more sense and is more "wikified". I am doing this as a 10-step process. while I complete this, please leave comments on this page until I'm done. Thanks! Katanada (talk) 05:28, 25 February 2008 (UTC)


STEP 1: Definition > COMPLETE
STEP 2: Characteristics > COMPLETE
STEP 3: Macroscopic Properties > COMPLETE
STEP 4: Microscopic Properties > NEEDS EXPANSION - Its currently "Stub-like"
STEP 5: "Gas Models" > COMPLETE
STEP 6: Special Topics > NEEDS EXPANSION - Its currently "Stub-like"
STEP 7: History > COMPLETE
STEP 8: References > COMPLETE
STEP 9: Clean-up > COMPLETE
STEP 10: Review > (THIS IS FOR OTHER WIKIPEDIANS TO DO!)

[edit] mass

The mass of a gas enters into the definition of specific volume, but apparently not elsewhere in the article.

A gas is 'ideal' at sufficiently low pressure, p. Then the fraction pV/T is proportionate to number of molecules of the gas, n. The constant value of the expression pV/nT is Boltzmann's constant. Deviations from the ideal state means that the number of molecules changes, due to condensation or to chemical reactions.

I suggest that the mass of the gas is treated late in this article. Mass is irrelevant in many applications.

Bo Jacoby (talk) 10:25, 26 February 2008 (UTC).

I'm currently editing from my phone so I'll keep it short for the moment and later finish. To answer the second part of your statement, I havent considered the mass of the gas. I agree that the mass is irrelevant so that's why its specific volume and not just volume. Specific volume is scalable for the amount of mass. Visit the NASA website on the reference list and read the section on density and specific volume. Katanada (talk) 14:08, 26 February 2008 (UTC)
I'm a little confused with the first statement you make. "A gas is 'ideal' at sufficiently low pressure, p." I'm not arguing it but I feel like theres two ideas in there that are a little confusing... a gas can act any which way it wants to at any given ambient conditions, whether under those conditions it follows the model stated by the "Ideal Gas" is a totally different thing. If we consider a "gas" as one model and an "Ideal Gas" as another then we can see where the two correlate (under what conditions they correlate). Whether they correlate more at "sufficiently low pressure" is fine but thats not what I'm trying to explain in the article. The model for an "Ideal Gas" has is own conditions and assumptions, thats the only thing I'm trying to display in the method of writing this article. Most people confuse the concept of an Ideal Gas and other simplifications of gases with the actual gas itself. Basically, I'm trying to have people say "This gas behaves as an Ideal Gas under these conditions" instead of "This gas is an Ideal Gas". I don't have any issue with your equations, I don't understand where that brings any more clarity to the statement. Katanada (talk) 23:28, 26 February 2008 (UTC)
Also, deviations from the "Ideal Gas model" is not necessarily just phase-changes or chemical reactions. I can theoretically squeeze enough gas into a container to where intermolecular forces would become significant enough to where the gas deviates from the ideal model. (this is just one example) Katanada (talk) 23:28, 26 February 2008 (UTC)

[edit] GA review

I quick-failed this article at GA because it seemed to have been submitted without reference to the GA criteria. It has no proper introduction (WP:LEAD), has no in-line citations, and does not conform to WP:MOS Jimfbleak (talk) 07:44, 27 February 2008 (UTC)