Argon instead of nitrogen?

[Brian]

I always have Argon around, and I never have nitrogen. Can I pressurize Penske shocks with Argon?

Thanks, Brian

[bimmer635csi]

Can you? Yes.

Should you? Probably not.

If you want the chemical bonding theory as to why, I can elaborate. But it is basically because Argon is monatomic and Nitrogen is a triple-bonded diatomic molecule.

[Dave Harmison]

It may be the same answer but in a different form, but I was told by a shock engineer that argon may dissolve into the oil whereas the nitrogen stays separate and keeps it pressurized.

Is that what all the chemical talk meant? It sounds about right that the small molecule would be more soluble than the large molecule, but I'm a mechanical engineer, hated chemistry class.

They didn't think CO2 would work either, but I don't know why.

Bottom line, use nitrogen.

[Rick Iverson]

When dealing with gas volumes, temperatures and pressures, you have to deal with the usual suspects:

Boyle's Law: P1V1 = P2V2

Charles' Law: V1/T1 = V2/T2

Gay-Lussac's Law: P1/T1 = P2/T2

The Combined Gas Law: P1V1/T1= P2V2/T2

And the Ideal Gas Law: PV=nRT

Now let’s visit about these:

IN THEORY, an ideal gas (as opposed to a real gas) is one where all collisions (Kinetic Molecular Theory - gas consists of molecules in constant random motion) between atoms or molecules in a closed system are perfectly elastic with no intermolecular attractive forces (all internal energy is kinetic in nature, and any change in internal energy is associated with a change in temperature). This is basically for the classroom, and by removing the molar mass (n) and the gas constant (R), you get the Combined Gas Law. The equation is simple P1V1/T1 before and P2V2/T2 after, where you fill in all but one of the variables, and solve for the unknown.

The Combined Gas Law is simply an algebraic aggregate of Boyle's, Charles' and Gay-Lussac's Laws, and it is really the meat and potatoes in this application. But there are properties of Ar and N2 that are necessary to consider.

Ar is an inert noble gas (Group VIIIA) and has an oxidation number of zero (electronic configuration is 1s2 2s2p6 3s2p6, with the third and valence orbital are full with eight electrons), which prevents it from readily forming compounds as well as being self-sufficient and does not need to be diatomic to be stable.

N2 is considered a dry, slow inactive inert gas due to its relatively non-reactive nature, and that it doesn't support moisture well. Conversely, O2 is a fast active gas that reacts with many materials (oxidation), and reacts with hydrogen readily to yield H2O.

Basically it comes down to this: the specific heat (heat required to change temperature of one kilogram of a substance by one degree) of Ar is half that of nitrogen (0.5203 KJ/(kgK) vs. 1.039 KJ/(kgK). This means it doesn't store energy well, but the gas constants for argon and nitrogen are similar (0.2081 vs. 0.2968 (same units as specific heats), indicating that they would change in temperature in a very similar manner when compressed.

So the short of it is, yes you can use Ar, but N2 is less expensise, readily available, and does a pretty good job.

V/r

Iverson

[Steve Demeter]

I haven't seen the orbital configuration of anything since about oh 1974. Almost forgot them.

[bill gillespie]

When dealing with gas volumes, temperatures and pressures, you have to deal with the usual suspects:

Boyle's Law: P1V1 = P2V2

Charles' Law: V1/T1 = V2/T2

Gay-Lussac's Law: P1/T1 = P2/T2

The Combined Gas Law: P1V1/T1= P2V2/T2

And the Ideal Gas Law: PV=nRT

Now let’s visit about these:

IN THEORY, an ideal gas (as opposed to a real gas) is one where all collisions (Kinetic Molecular Theory - gas consists of molecules in constant random motion) between atoms or molecules in a closed system are perfectly elastic with no intermolecular attractive forces (all internal energy is kinetic in nature, and any change in internal energy is associated with a change in temperature). This is basically for the classroom, and by removing the molar mass (n) and the gas constant (R), you get the Combined Gas Law. The equation is simple P1V1/T1 before and P2V2/T2 after, where you fill in all but one of the variables, and solve for the unknown.

The Combined Gas Law is simply an algebraic aggregate of Boyle's, Charles' and Gay-Lussac's Laws, and it is really the meat and potatoes in this application. But there are properties of Ar and N2 that are necessary to consider.

Ar is an inert noble gas (Group VIIIA) and has an oxidation number of zero (electronic configuration is 1s2 2s2p6 3s2p6, with the third and valence orbital are full with eight electrons), which prevents it from readily forming compounds as well as being self-sufficient and does not need to be diatomic to be stable.

N2 is considered a dry, slow inactive inert gas due to its relatively non-reactive nature, and that it doesn't support moisture well. Conversely, O2 is a fast active gas that reacts with many materials (oxidation), and reacts with hydrogen readily to yield H2O.

Basically it comes down to this: the specific heat (heat required to change temperature of one kilogram of a substance by one degree) of Ar is half that of nitrogen (0.5203 KJ/(kgK) vs. 1.039 KJ/(kgK). This means it doesn't store energy well, but the gas constants for argon and nitrogen are similar (0.2081 vs. 0.2968 (same units as specific heats), indicating that they would change in temperature in a very similar manner when compressed.

So the short of it is, yes you can use Ar, but N2 is less expensise, readily available, and does a pretty good job.

V/r

Iverson

From my days at FSU I learned the really important stuff: The angle of the dangle is directly proportionate to the heat of the meat, if the mass of the a-- remains constant, etc,...you know the rest !