---
title: "A student investigates a reaction that may be used in a thermal-energy storage system. The reaction-energy profile is shown in the diagram.  Which choice correctly compares the forward and reverse activation energies and classifies the forward reaction?"
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url: "https://nerd-notes.com/ubq/119332/"
date_modified: "2026-08-19T12:39:50+00:00"
---

# A student investigates a reaction that may be used in a thermal-energy storage system. The reaction-energy profile is shown in the diagram.

Which choice correctly compares the forward and reverse activation energies and classifies the forward reaction?

A student investigates a reaction that may be used in a thermal-energy storage system. The reaction-energy profile is shown in the diagram.

Which choice correctly compares the forward and reverse activation energies and classifies the forward reaction?

![Draw a grayscale reaction-energy profile on bare Cartesian axes with no gridlines or numerical tick marks. Label the vertical axis Potential energy and the horizontal axis Reaction progress. A single solid curve begins with a short horizontal segment at relative energy 40 near the left side, annotated Reactants. The curve rises smoothly to one maximum at relative energy 100 near the center and then falls to a short horizontal segment at relative energy 70 near the right side, annotated Products. Add a vertical dashed double-headed arrow from the reactant energy level to the maximum labeled \(E_{a,\text{forward}}\). Add a second vertical dashed double-headed arrow from the product energy level to the same maximum labeled \(E_{a,\text{reverse}}\). No legend is present. No other curves, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787143190-5yF4HF.jpg)

- **A.** \(E_{a,\text{forward}} > E_{a,\text{reverse}}\); the forward reaction is exothermic.
- **B.** \(E_{a,\text{forward}} > E_{a,\text{reverse}}\); the forward reaction is endothermic.
- **C.** \(E_{a,\text{forward}} < E_{a,\text{reverse}}\); the forward reaction is endothermic.
- **D.** \(E_{a,\text{forward}} < E_{a,\text{reverse}}\); the forward reaction is exothermic.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119332/*