Potential Energy of gas

An ideal gas doesn't have potential energy. PE is due to intermolecular forces.

BUT

PE is negative - the stronger the forces are the lower the PE.
That's why you have to supply energy to break bonds. To get back to a zero energy state.
Ultimately it because of the way we define zero PE.

If molecules are close together , the PE is more negative - its prop to -1/r

its confusing referring to larger and smaller.

Is -1 bigger than -2 or smaller?

Well I guess it's magnitudeally bigger but vectorically smaller? :P

Well this brings me to the point

If internal energy = Ep + Ek
And an increasing temperature means an increase in internal energy

Surely that means even during phase change, T should increase because Ep is increasing ( i.e. getting less negative )


Posted from TSR Mobile

True enough, adding heat will increase internal energy. However, increasing E_p does not imply increasing T.

Temperature depends on kinetic energy, as in the equation $E = \frac{3}{2}kT$ where E is the mean translational kinetic energy of a particle in the gas.

Increased potential energy means increased separation and disorder. If work must be done to break bonds and thus separate particles, then their potential energy has increased.

By the way, in my opinion 'increasing potential energy' is not ambiguous, it means more positive. We really care about changes in potential energy, so don't worry about the fact that it is defined as negative.

I get 100% what your saying. But how come my statement is falsified?

If IE = Ep + Ek, and T ∝ IE, then sureley Ep ^ means IE ^ means T ^?

Temperature is not proportional to internal energy; it is only proportional to kinetic energy.