Physics Question

[CuriousAsHeck]

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This has been bugging me for a while now.

Mathematically, the Ideal Gas law can be stated as: PV = nRT, which is essentially a combination of Boyle's Law (P1V1 = P2V2; P and V are inversely proportional), Charles Law (V1/T1 = V2/T2; V and T are directly proportional) and Avogadros' Law (n1/ V1 = n2/V2; n and V are directly proportional).


Theoretically, The Ideal Gas states that in order for a gas to be ideal, it must have -

a) no volume
b) no intermolecular forces


Then it goes on to say that a gas acts most ideal at Low Pressure and High Temperature. My question is this - according to the mathematical formula, a low pressure gives a HIGH volume (since P and V are inversley related). But the theory states that a gas has to have NO (or negligible) volume in order to be ideal.

Aren't they contradicting each other?

Like I said above, this has been bugging me for a while now. I would really appreciate it if anyone can clear this up.


Thank You

 

[i77ac]

This has been bugging me for a while now.

Mathematically, the Ideal Gas law can be stated as: PV = nRT, which is essentially a combination of Boyle's Law (P1V1 = P2V2; P and V are inversely proportional), Charles Law (V1/T1 = V2/T2; V and T are directly proportional) and Avogadros' Law (n1/ V1 = n2/V2; n and V are directly proportional).


Theoretically, The Ideal Gas states that in order for a gas to be ideal, it must have -

a) no volume
b) no intermolecular forces


Then it goes on to say that a gas acts most ideal at Low Pressure and High Temperature. My question is this - according to the mathematical formula, a low pressure gives a HIGH volume (since P and V are inversley related). But the theory states that a gas has to have NO (or negligible) volume in order to be ideal.

Aren't they contradicting each other?

Like I said above, this has been bugging me for a while now. I would really appreciate it if anyone can clear this up.


Thank You

I'll try to make it brief. when we assume that the ideal gas has no volume, we mean that the individual gas molecules have no volume, not the collective volume of the gas as a whole. in other words, ideal gas DO have volume, but the molecules that make up the gas DO NOT have volume.

so when we have low pressure, yes we do have high volume (all else being equal), but the molecules are still considered not to have any volume. and as a side note, low pressure and high temp is condition in which the molecules will interact very little, which we can assume to be "ideal."

hope that helps.

 

[sdnstud]

You have mistaken the volume of individual gas molecules with the volume of the container that contains the gas molecules.

In PV=nRT. the V= volume of the container the contains the gas molecules. As V goes up (the volume of the container increase), the gas is more ideal.

The ideal gas law states that ideal gas has no volume. That is, the individual gas molecules occupy neglible volumes (they don't take up any space). the more neglible the volume of the gas molecules, the more ideal is the gas.

They ARE related. Look at it this way...if the volume of the container increases ALOT, it makes the volume of individual gas molecules more neglible.

This has been bugging me for a while now.

Mathematically, the Ideal Gas law can be stated as: PV = nRT, which is essentially a combination of Boyle's Law (P1V1 = P2V2; P and V are inversely proportional), Charles Law (V1/T1 = V2/T2; V and T are directly proportional) and Avogadros' Law (n1/ V1 = n2/V2; n and V are directly proportional).


Theoretically, The Ideal Gas states that in order for a gas to be ideal, it must have -

a) no volume
b) no intermolecular forces


Then it goes on to say that a gas acts most ideal at Low Pressure and High Temperature. My question is this - according to the mathematical formula, a low pressure gives a HIGH volume (since P and V are inversley related). But the theory states that a gas has to have NO (or negligible) volume in order to be ideal.

Aren't they contradicting each other?

Like I said above, this has been bugging me for a while now. I would really appreciate it if anyone can clear this up.


Thank You