partial molar property,
denoted by an
overline; indicates the change in an extensive thermodynamic
variable as the number of particles in a system changes. This
notation will be used in our discussion of multiphase systems, as
partial molar properties are useful for discussing changes to a
system's property upon a change in the number of a single component
mechanical equilibrium
if a system has movable boundaries, at
equilibrium the pressure of the system will be equivalent to the
pressure of the surroundings
chemical equilibrium
if a system has open boundaries, at
equilibrium the chemical potential of each component of the system
will be equivalent to the chemical potential of each component in
the surroundings