Irreversible process Irreversible process:both system and surroundings cannot be exactly restored to their respective initial states after the process has occurred. "System"itself could be reversible;irreversibility exists in surrounding. all actual processes are irreversible.spontaneous events are irreversible examples: Heat transfer through a finite temperature difference Unrestrained expansion of a gas or liquid to a lower pressure Spontaneous chemical reaction ● Spontaneous mixing of matter at different compositions or states Friction-sliding friction as well as friction in the flow of fluids Electric current flow through a resistance Magnetization or polarization with hysteresis Inelastic deformation 上游通大学 April 8,2018 14 SHANGHAI JIAO TONG UNIVERSITYApril 8, 2018 14 Irreversible process Irreversible process: both system and surroundings cannot be exactly restored to their respective initial states after the process has occurred. - “System” itself could be reversible; irreversibility exists in surrounding. all actual processes are irreversible. spontaneous events are irreversible examples: • Heat transfer through a finite temperature difference • Unrestrained expansion of a gas or liquid to a lower pressure • Spontaneous chemical reaction • Spontaneous mixing of matter at different compositions or states • Friction—sliding friction as well as friction in the flow of fluids • Electric current flow through a resistance • Magnetization or polarization with hysteresis • Inelastic deformation