Internal energy of a gas

[nokia8650]

[SOLVED] Internal energy of a gas

Is the internal energy of a gas simply the total kinetic energy possesed by the particles? I ask this, since I have read this to be the case, however I have also read that when changing state, eg. from liquid to gas, the latent heat is the energy required to increase the potential enrgy of the particles, as well as do work against external pressure. If energy is put into increase the potential energy, surely some of the internal energy of the gas is potential energy, as well as kinetic energy, isn't it?

Thanks

 

[Hootenanny]

surely some of the internal energy of the gas is potential energy, as well as kinetic energy, isn't it?

You are indeed correct. The internal energy of a gas can be thought of as the sum of the kinetic and potential energies of the constituent molecules. However, note that for the special case of an ideal gas, it is assumed that the molecules do not interact, i.e. there is no potential energy. Hence, for an ideal gas the internal energy is the kinetic energy of the molecules, since there is no potential component.

Further reading: http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/inteng.html" [Broken]

I hope that makes sense.

 

[nokia8650]

Thank you ever so much, it makes a lot more sense now!

 

[Hootenanny]

Thank you ever so much, it makes a lot more sense now!

A pleasure

Don't forget to mark this thread a 'solved' when your done, thanks.