PH 122 Chapter Notes - Chapter 20: Thermodynamics, Differential Form, Ator
Document Summary
A one-way process is irreversible if it cannot be reversed by means of only small changes in their environment. In practice, there are many real-life events that follow this description even though the reversed process would not violate any energy conservation principle. Consider a closed system, i. e. , a system where the total en- ergy does not change. The direction of a process is deter- mined by the change quantity known as entropy that we will denote by s, which change we will denote by s. If an irreversible process oc- curs in a closed system, the entropy s of the system always in- creases; it never decreases. These are some important characteristics of s: entropy does not obey a conservation law like energy, changes in entropy determine the direction of time. 1. 2 change in entropy in terms of state prop- erties. Consider the free expansion of an ideal gas.
