化工热力学 热力学第二定律--第五章熵的定义概念5.6-1

Chapter 5 THE SECOND LAW OF THERMODYNAMICSHowever the integral of dQ/T for the irreversible process does not give ΔS from B to A(然而不可逆过程从B至A的积分得不到ΔS ). The calculation of entropy changes must always be for reversible conditions. The integral of

dQ/T is equal to the change in entropy for a reversible process only.

Chapter 5 THE SECOND LAW OF THERMODYNAMICSSo far, only the entropy changes of the working substance of heat

engines have been considered. Since no limitations have been placed on such substances, the property of entropy must be ascribed to all matter.

Chapter 5 THE SECOND LAW OF THERMODYNAMICSFurthermore, if heat transfer to the working substance of a reversible heat engine causes its entropy to change in the amount ΔS=∫dQR/T, then heat transfer in any reversible process should cause entropy changes given by the same equation .