---
title: "Phase Change — AP Chem Definition & Exam Connections"
description: "Phase change is a physical transition between solid, liquid, and gas driven by IMFs, not bond breaking. Key for entropy, heating curves, and ΔG = 0 logic."
canonical: "https://fiveable.me/ap-chem/key-terms/phase-change"
type: "key-term"
subject: "AP Chemistry"
---

# Phase Change — AP Chem Definition & Exam Connections

## Definition

Phase change refers to any transformation or transition that occurs between different states of matter, such as from solid to liquid, liquid to gas, etc.

## Review

### Related Terms

- [Boiling Point](/ap-chem/key-terms/boiling-point): Boiling point is the temperature at which a substance changes from its liquid state to its gaseous state under standard atmospheric pressure.
- [Melting Point](/ap-chem/key-terms/melting-point): Melting point is the temperature at which a solid substance changes from its solid state to its liquid state under standard atmospheric pressure.
- [Sublimation](/ap-chem/key-terms/sublimation): Sublimation is when a solid directly transforms into its gaseous state without first becoming a liquid.