Abstract
It is impossible that proving the internal energy change has the relations with volume and pressure. About the second law of thermodynamics, many mistakes of formulations need to be put right and modified, and many new concepts are surveyed too. The equality and inequality on the ratios of internal energy change to temperature and work to temperature are discussed. The relation between the reversible paths and their realistic paths is also researched. In an isothermal process, the internal energy change for the gases is equal to zero, but the internal energy change is not equal to zero for the phase transition or chemical reaction. The Clausius inequality can be derived from the equation calculating the internal energy change in mathematics; it is the new method proving the Clausius inequality. These change laws of thermodynamics could be applied to the gravitational field and mechanical motion and so on.
Highlights
In text, the heat and work are taken as positive if the energy is supplied to the system and negative if the energy is lost out of the system
The Clausius inequality can be derived from the equation calculating the internal energy change in mathematics; it is the new method proving the Clausius inequality
According to the first law of thermodynamics [1] [2] [3], if the expansion work doesn’t exist, the internal energy change is equal to the non-expansion work in the adiabatic process
Summary
The heat and work are taken as positive if the energy is supplied to the system and negative if the energy is lost out of the system. Wother expresses the other work ( called the non-expansion work), and − pdV indicates the pressure-volume work (namely the expansion work). According to the first law of thermodynamics [1] [2] [3], if the expansion work doesn’t exist, the internal energy change is equal to the non-expansion work in the adiabatic process. If any work doesn’t exist, the internal energy change is equal to the heat in a constant volume process
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