---
title: "Energy Diagram — AP Chem Definition & Exam Guide"
description: "An energy diagram graphs the energy of reactants and products during a reaction, showing whether a process is exothermic or endothermic plus its activation energy."
canonical: "https://fiveable.me/ap-chem/key-terms/energy-diagram"
type: "key-term"
subject: "AP Chemistry"
---

# Energy Diagram — AP Chem Definition & Exam Guide

## Definition

An energy diagram is a visual representation of the energy changes that occur during a chemical reaction. It shows the initial and final energy levels of the reactants and products, as well as the activation energy required for the reaction to proceed.

## Review

### Related Terms

- [Activation Energy](/ap-chem/key-terms/activation-energy): Activation energy refers to the minimum amount of energy required for a chemical reaction to occur. It's like the push needed to start climbing up that first hill on a roller coaster.
- [Exothermic Reaction](/ap-chem/key-terms/exothermic-reaction): An exothermic reaction releases heat or thermal energy into its surroundings. It's like going down a steep drop on a roller coaster and feeling all that rush of excitement.
- [Endothermic Reaction](/ap-chem/key-terms/endothermic-reaction): An endothermic reaction absorbs heat or thermal energy from its surroundings. It's like going up a hill on a roller coaster, needing extra input of external energy to climb higher.