Ideal gas

In general, which of the gases, N2, CO, and H2, would you expect to behave the most and least ideally?

I have no idea how to determine this...can someone help me? Thank you!

 

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Hmm
I'm guessing that the question wants you to take into account the first correction term due to using the Van der Waals equation of state instead of the ideal gas EoS. I'd hazard a guess at H2 being most ideal, as it is smallest.
http://en.wikipedia.org/wiki/Van_der_Waals_equation has an explanation and derivation.

 

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How do you know?

As I know there are 2 correction factors for real gas: one for intermolecular attractions and one for molecular volume...but I still don't know how to determine which gas is the most ideal and which is the least ideal...

 

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How do I know what? As to determining actual answers, you'd need numerical values. Is there any more info with the question?

 

Um...I mean how can you know which of the gases is more ideal?

No, there aren't any numerical values, unfortunately...but the question says "in general"...

 

Well, just from general arguments, H2 is easily the smallest, and it has the lowest BP/MP of the three, so it is most ideal. I'd have put CO and N2 at about the same size, but due to oxygen's electronegativity, I'd have thought that intermolecular attractions between CO were greater than between N2, so CO would be least ideal.

 

no gas is ideal.... ever...

-MT

 

Hi geodesic,

By smallest, do you mean smallest in terms of mass or in terms of the radius of the molecule?

 

h2 is also the most reactive

 

H2 is smallest in both, but I meant in terms of volume.

In general true, but I thought this sounded more like a thermodynamics/statistical physics question.

 

CO would work ideally. Ideally suitable carbon monoxide, ideal invincible death.

 

Anyways ideal gas has no intermolecular forces (also called Van Der Wall)
So you have to figure out which of the three has which forces.
Does N2 have intermolecular forces? yea VDW
Does CO have intermolecular forces? umm I don think so.
Does H2 have intermolecular forces? yea...VDW

I would go with CO.

 

Absolute rubbish. N2 and H2 have Van der Waal's, or induced dipole interactions. The electronegativity of the oxygen atom causes the shared electron in the C=O bond to be closer to the O atom, creating a small dipole. Hydrogen bonding only occurs in hydrogen atoms bonded to oxygen atoms, where the oxygen's electronegativity leaves an almost unshielded proton, which forms relatively strong (compared to Van der Waal's and dipole) bonds with oxygen, nitrogen or fluorine atoms. Hydrogen bonding is the reason that water has such a high boiling point.

 

huh? thatz not wha I wrote.

 

Given that my post with the quote in is dated at five hours before you made your edit, you may want to revise your last statement.

 

I don't understand this question. I hope I won't come accross this in school. I am a chemistry major. sheesh!

 

It has to do with Wan Der Val bonds...and thats all I know.

 

kingwinner asked:
"In general, which of the gases, N2, CO, and H2, would you expect to behave the most and least ideally?"
You replied:

I think the correct answer is H2, certainly it is not CO. Both N2 and H2 are symmetric molecules so neither end is more charged than the other is. As thermal energy is removed CO molecules will then try to hook up in chains with the positive "C" end of one near the negative "O" end of another. That is why at modestly low temperatures the ideal gas law will become less valid (pressure will drop faster than linearly with absolute temperature. Dropping very rapidly as solid or liquid CO is approached.)

I do not know the binding energy of CO but know that H2's is reasonable high, so strongly suspect that the failure of the ideal gas law as higher temperatures are approached due to disassociation of the molecules is not much different of may even favor H2 also. I suspect that N2 may disassociate as high temperatures are approached before either CO or H2. When the molecules do begin to disassociate, the pressure will rise more rapidly than linearly with the absolute temperature - it is as if more atoms were being added to the chamber.

All this just by logic and physics - it would be cheating to look up the chemical facts. Perhaps I am wrong, - if so please some chemist correct me, but I am quite confident that H2 behaves like an ideal gas over a greater temperature range than CO does. I.e. confident your answer is wrong.

PS - I answered his question seriously, but on your joke: Either of the other two will kill you also. I slightly knew two men who contentedly died breathing N2 inside a large bell jar while working on a satellite. Few people realize that man has no desire for oxygen. Humans breath to get rid of CO2. So long as you can do that (for example in a pure N2 atmosphere as they were unknowingly) you contentedly inhale and exhale until you lose consciousness and continued to inhale and exhale until the mussels no longer work for lack of oxidizer. The men were discovered around 6PM because they failed to come to their waiting car pool ride home. Instead of hand cranking up the heavy steel bell jar, they had raised it only a foot or so and crawled under, not realizing they had left the dry nitrogen flowing. (It is used to keep moist air out, especially if any part of the satellite has still cold refrigerated componets, such as an IR detector.)

 

How about this!

The most ideal gas would be "fart," which I believe contains mostly nitrogen.

It is the cheapest, most efficient, most ecologically sound gas made. All you have to do is eat more beans!