Ideal vs Real Gases

[osimsDDS]

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I want to make a list between ideal vs real gases so here it goes:

Ideal:
-volume is negligible
-elastic
-at STP volume = 22.4L
-no intermolecular attractions present

Real:
- at STP volume is lower than 22.4L, therefore low pressure and high temperature will make the real gas act more like an ideal gas...
-inelastic collisions
- intermolecular attractions present
-volume is present

Someone please add to this or even make it better...thanks!!!

 

[Neuro178]

I want to make a list between ideal vs real gases so here it goes:

Ideal:
-volume is negligible
-elastic
-at STP volume = 22.4L
-no intermolecular attractions present

Real:
- at STP volume is lower than 22.4L, therefore low pressure and high temperature will make the real gas act more like an ideal gas...
-inelastic collisions
- intermolecular attractions present
-volume is present

Someone please add to this or even make it better...thanks!!!

Looks good to me! Not sure about the part I bolded though... I think that sounds right, but I don't have my notes on me to check it. But you are probaby right!

 

[rippinitez]

My understanding was that real gases behave ideal unless under high pressure and low temperature. Correct me if I'm wrong.

 

[osimsDDS]

think about this, if you have high pressure that means molecules are condensed, low temperature means kinetic molecular theory of gases is negated...it doesnt make sense

I believe your thinking of gases and their solubility in aqueous solutions....gases can be soluble in aqueous solution under high pressure and low temperature!!!

 

[Neuro178]

Under ideal gases, add:
Move in a random motion.

Also, to end the disparity, from wikipedia:

"The conditions in which a real gas will behave more and more like an ideal gas is either at very high temperatures (as the molecules of the gas have so much energy that the intermolecular forces and energy lost in collisions is negligable) and at very low pressures (as the molecules of the gas rarely collide or come into close enough proximity for intermolecular forces to be significant)."

Problem solved. Yay wikipedia!

 

[Mstoothlady2012]

very nice thread! I was about to open a thread on ideal gases and the search result brought this up, I guess I missed it for some reason. Anyways this is such a common topic that shows up on DAT and it is very important to understand.

I agree real gases behave like ideal gases at low pressure and high temperature.

Gases can dissolve better at high pressure...hmm I am not sure what part temperature plays in dissolving???

Also for intermolecular forces in ideal gases....there are none what so ever right?

 

[PinkDDS]

I understand that V(real) > V(ideal) because a real gas has volume, but why at STP volume is lower than 22.4 for a real gas?

 

[osimsDDS]

I understand that V(real) > V(ideal) because a real gas has volume, but why at STP volume is lower than 22.4 for a real gas?

At STP we are talking about ideal gases and the volume is 22.4L because no intermolecular attractions occur, however, for real gases since there are intermolecular attractions going on the volume is going to be a tiny bit less...therefore real gases will behave as ideal gases when the P is decreased and the T increased because remember...

Decrease P will Increase V
Increase T will Increase V

So if you decrease the pressure and increase T it will balance out and get your ideal gas to around 22.4L like that of an ideal gas and you can say therefore a real gas will act idealy...