A change of phase may or may not occur with?

• A. State
• B. Temperature
• C. Change of State
• D. Volume

Answer: (C)

A phase change is defined by a change in the physical state of matter (solid, liquid, gas). If a substance actually moves from one state to another, that is a change of state, which is exactly what a phase change is. Conditions like temperature and pressure determine when this boundary is crossed, but the defining feature is the state itself changing. Volume can change during a phase change, and temperature or pressure drives the transition, but the essential point is that a phase change is a change of state.