---
title: "Chemical Change — AP Chem Definition & Exam Evidence"
description: "A chemical change transforms substances into new ones with different compositions. Learn the four CED evidence signs (gas, precipitate, color, heat/light) for AP Chem."
canonical: "https://fiveable.me/ap-chem/key-terms/chemical-change"
type: "key-term"
subject: "AP Chemistry"
---

# Chemical Change — AP Chem Definition & Exam Evidence

## Definition

A Chemical Change is any change resulting in the formation of new chemical substances. At molecular level, bond making and bond breaking process occurs during this type of changes.

## Related Study Guides

- [4.1 Introduction to Reactions](/ap-chem/unit-4/intro-for-reactions/study-guide/LNQzVvZYjXxZMmXDubVP)

## Review

### Related Terms

- [Combustion](/ap-chem/key-terms/combustion): A chemical reaction that occurs between a fuel and an oxidizing agent, producing heat and light.
- [Oxidation](/ap-chem/key-terms/oxidation): A process where a substance loses electrons or increases in oxidation state.
- Reduction: A process where a substance gains electrons or decreases in oxidation state.