Total translational kinetic energy of a gas molecule...?

Question

A 5m^3 vessel contains gas N2 gas at 27C and 3 Pa.

Find the total translational kinetic energy, the average kinetic energy per molecule, and the total internal energy of the gas.

KE = 3/2N.kb.T

Please help me solve this. Is this supposed to be an ideal gas problem?

Answer 1

Well, yes, this is an ideal gas problem. Like all problems of this type, we are looking for solutions that deals with a system that is in thermodynamic equilibrium.

And that means (1) There is NO net translational kinetic energy, i.e. the gas is NOT moving in any particular direction, because it is in equilibrium. (2) All the gas particles are bouncing in all different directions inside the container, so there is an AVG KE per particle,and this would be related to the temperature and pressure.

Now, the internal energy of a thermodynamic system, or a body with well-defined boundaries, denoted by U, is the total of the kinetic energy due to the motion of molecules (translational, rotational, vibrational) and the potential energy associated with the vibrational and electric energy of atoms within molecules.

Here, U = KE, because the system is in equilibrium and is contained within the vessel, and no heat is being exchanged.

I leave the calculations involved in this problem to you.