More About Liquid-Gas Equilibrium

Re-edited 12/30/2019

Most types of molecules that can exist both in gaseous and liquid form are not symmetrical, both mechanically and electrically. There is a distribution of mass and electrical charge within the molecule which can result in molecule having a rotation moment that can be exchanged with other molecules and into linear momentum and back.

Let's imagine we have a semi filled container with a single type of molecules with uneven spatial distribution of mass and electrical charges and some of it exists in gas form above the surface of liquid where there is a continuous exchange of molecules from the liquid phase into gas phase and back.

There is a continuous motion of molecules which stands for the temperature and pressure of the mass of that liquid.

Due to spatiality of the electrical charges the molecules in liquid form tend to arrange in a matrix like pattern at least temporarily and in limited volumes. Electrostatic forces between water molecules in a liquid are also called hydrogen bonds.

Image taken from https://www.mbi-berlin.de/en/research/projects/3.1/highlights/MolStructDynamics-2006.html (now link is broken) trying to figure water molecules in a matrix within liquid phase.
Molecules moving "freely" in gaseous form have much higher speeds because their pressure have to equate the pressure of the more numerous but slower moving molecules in liquid form. Also it is thought gas molecules in a closed container move around following a Maxwell-Boltzmann distribution of their linear speeds.

Molecules in both phases besides linear speed that creates pressure have a rotation speed that also carries energy.

All molecules in both phases move around in complex patterns. Those in liquid phase oscillate around in a circular motion and move linearly together in wave like patterns within a matrix.

In the gas phase there is rotation and "random" linear motion between two collisions when molecules exchange linear and rotation speed while molecules with higher energy loose some to those with lower.

At the surface there is a continuous exchange of molecules between gas and liquid.

Rotation moment of the molecules caught in the matrix of a liquid is more uniform then the rotation moment of molecules in gas form because of hydrogen bonds.

The distribution of momentum and energy necessary for the molecules to escape from the liquid is also within a narrower band than normal distribution or just above the energy necessary to break electric bondage at the surface while the energy lost by molecules moving within a normal distribution that are "caught" at the surface of the liquid varies within a normal distribution. (Maxwell-Boltzmann). However they collide right away with the other molecules in gas form and go back to a normal distribution of speed.

However heat pumps have one area where molecules are converted from gaseous form to liquid (condensation) and another one where liquid is converted back to gas (evaporation). Evaporated or escaped molecules do not meet right away with those of a normal distribution.

We can say the two surfaces separating gas and liquid phase in a heat pump can play the role of the gate in Maxwell's experiment, regulating "entropy" by changing the distribution of gas molecule from normal distribution to a narrow band distribution.

We know from practice that heat pumps are over unity devices (producing more energy than consume).

Trying to summarize what i wrote in this blog post. http://georgesblogforfriends.blogspot.com/2017/08/about-liquid-gas-phase-equilibrium.html written triggered by the observation of an apparent energy imbalance in practical devices like described here http://georgesblogforfriends.blogspot.com/2014/06/btu.html