What is the difference between a phase and a phase transition?
a. a phase is a region with homogeneous (uniform) properties and a conversion between states is called a "phase transition"
c. a phase is a physical property and a phase transition is a chemical change.
b. a phase is a chemically distinct state of matter and a phase transition is a chemical change.
d. none of the above?

a. A phase is a region with homogeneous (uniform) properties and a conversion between states is called a "phase transition"

Explanation:

Hello,

In this case, we first must consider that a phase is defined in terms of the molecular distribution of a substance, therefore, for a single phase, its properties must be homogeneous to be considered as it. On the flip side, the phase transition is the correct term regarding the "change of state" of a substance, say melting, freezing, deposition, sublimation, condensation and boiling. Consequently, the answer is:

a. A phase is a region with homogeneous (uniform) properties and a conversion between states is called a "phase transition"

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