Fig. shows the scheme of energy exchange between a gas system and the surroundings. The thermal equilibrium is not Eq. 3+Eq. 4 = 0. The gas system loses or gains the long-term kinetic energy and system potential with spontaneous system work. System work is always positive in the endothermal and exothermic processes and offset by the outer counterparts. The details of how liquid molecules exchange heat with the surroundings via the container walls are unclear. However, since the liquid temperature likely equals gas, the long-term kinetic energy of gas molecules is converted into the vibrational energy of liquid molecules. Therefore, the energy change substantially exchanges system work and system potential. It is quite different from classical mechanics, in which the kinetic energy of particles can be converted into potential through doing work. Still, the work always equals the kinetic energy loss and the potential increase. Analogical to a gas system at Tc, 𝑅𝑇 = , the system work is zero due to VL=VG. However, this is a case in which the energy exchange is interrupted due to a lack of gas molecules joining the exchange. Consequently, the liquefaction stops no matter how high the pressure is imposed. In other words, the system substantially becomes an adiabat system. At other temperatures of an isolated system, the system work is not equal to the increase of system potential; inversely, it is usually much larger than the kinetic energy loss and less converted into the system potential. , That is to say, the system amplifies the kinetic energy loss.