---
title: "A student investigates the dissolution of ammonium nitrate in water, as represented by the equation below.  \\[\\text{NH}_4\\text{NO}_3(s) \\rightarrow \\text{NH}_4^+(aq) + \\text{NO}_3^-(aq)\\]  When the solid dissolves in water inside an insulated calorimeter, the temperature of the water decreases. The reaction energy profile for this process is shown. Based on the diagram, which of the following correctly classifies the process and compares the total enthalpy of the products to that of the reactants?"
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url: "https://nerd-notes.com/ubq/119783/"
date_modified: "2026-08-21T08:12:20+00:00"
---

# A student investigates the dissolution of ammonium nitrate in water, as represented by the equation below.

\[\text{NH}_4\text{NO}_3(s) \rightarrow \text{NH}_4^+(aq) + \text{NO}_3^-(aq)\]

When the solid dissolves in water inside an insulated calorimeter, the temperature of the water decreases. The reaction energy profile for this process is shown. Based on the diagram, which of the following correctly classifies the process and compares the total enthalpy of the products to that of the reactants?

A student investigates the dissolution of ammonium nitrate in water, as represented by the equation below.

\[\text{NH}_4\text{NO}_3(s) \rightarrow \text{NH}_4^+(aq) + \text{NO}_3^-(aq)\]

When the solid dissolves in water inside an insulated calorimeter, the temperature of the water decreases. The reaction energy profile for this process is shown. Based on the diagram, which of the following correctly classifies the process and compares the total enthalpy of the products to that of the reactants?

![A grayscale reaction energy profile with bare axes. The vertical axis has an upward arrow labeled Enthalpy (kJ/mol). The horizontal axis has a rightward arrow labeled Reaction Progress. A solid horizontal line segment on the left representing reactants is labeled \(\text{NH}_4\text{NO}_3(s)\). A smooth solid curve rises from this reactant plateau to an energy maximum and then descends to a higher horizontal line segment on the right labeled \(\text{NH}_4^+(aq) + \text{NO}_3^-(aq)\). A vertical dashed arrow pointing upward from the reactant level to the product level is labeled \(\Delta H > 0\). No other particles, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787299940-bTqtxh.jpg)

- **A.** The process is exothermic, and the products have a lower enthalpy than the reactants.
- **B.** The process is exothermic, and the products have a higher enthalpy than the reactants.
- **C.** The process is endothermic, and the products have a lower enthalpy than the reactants.
- **D.** The process is endothermic, and the products have a higher enthalpy than the reactants.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119783/*