How to understand the notion of critical temperature in thermodynamics?

Question

I just want to verify my understanding of the notion of critical temperature of fluids, because the more I read about it in the literature I become more and more confused.

My main clue for understanding this notion is the statement that latent heat becomes zero at the critical temperature. That is, no heat input is required to cause a phase transition from liquid to gas, and this implies also that if a piece of supercritical fluid is thrown into a low pressure area than the whole piece evaporates immediately.

Therefore I believe the critical temperature to be simply a measure of the natural strength of intermolecular attraction forces - above the critical temperature the molecules have enough kinetic energy to overcome their attractive forces (no external "help" is required). This seems to me consistent with Dimitri Mendeliev's term for critical temperature, "absolute boiling point".

I know my question seems like a bit strange question, since it is mainly a verification question, but i really need help to understand this notion. I'll also be glad to hear different approaches to understand/gain intuition about "critical temperature".

Answer 1

The surface energy of condensed matter generally decreases with increasing temperature because the increasing molecular vibration combats cohesion. The critical temperature is the temperature where the surface energy has dropped to zero. At this and higher temperatures, there's no driving force to form a condensed phase.