Thermal Concepts Ideal Gas Question

[Jenna26]

"Molecules have potential energy because of the intermolecular forces."

Ideal Gas: "there are no intermolecular forces"

so does this mean an ideal gas doesn't have potential energy?

I know it's a simple question, but i'd appreciate an explanation. Thanks!

[Award Winning Boss]

You're right. Since there's no force between them, then there can't be any potential energy otherwise it is possible that they'd affect other molecules. Which they don't unless they collide with each other.

[Guest Lognarithm]

An Ideal gas has Kinetic energy according to E_k=3/2kT=1/2mv². Since potential energy in classical terms is E_p=mgh, we see that gravity does not affect the molecules in the system, meaning the energy is purely based on the average velocity of the system, which translates into average temperature. IMF's are basically just potential energy because they require energy to break and release energy, similarly to how you have to push a ball up a hill to let it roll down again (translating PE into KE). In other words, you have to add energy to get a higher velocity, and increase the KE according to E_k above.