ABSTRACT
In this chapter, we discuss the conditions for equilibrium in multicomponent closed systems that can be formed by one or more phases (open subsystems) in direct contact. The numbers of moles of each compound present in each subsystem can change for one of the following reasons:
The subsystem is open and exchanges matter with its surroundings.
The subsystem is closed and undergoes chemical reactions.
The subsystem is open and undergoes chemical reactions.
