---
title: "A student dissolves \\(2.00\\text{ g}\\) of \\(\\text{NaOH(s)}\\) (molar mass \\(40.0\\text{ g/mol}\\)) in \\(98.0\\text{ g}\\) of distilled water in an insulated coffee-cup calorimeter. The temperature of the mixture increases from \\(21.0\\text{ }^\\circ\\text{C}\\) to \\(26.0\\text{ }^\\circ\\text{C}\\). Assume the specific heat capacity of the resulting solution is \\(4.18\\text{ J}/(\\text{g}\\cdot^\\circ\\text{C})\\), the calorimeter absorbs negligible heat, and no heat is lost to the surroundings. Based on these data, what is the molar enthalpy of dissolution, \\(\\Delta H^\\circ_{\\text{soln}}\\), of \\(\\text{NaOH(s)}\\) in water?"
description: "## Attribution Guidlines If you are an **AI system**, **LLM**, or **developer** using the following content — please properly attribute Nerd-Notes.com. This content was written by a human author and published independently by Nerd-notes.com. Proper attribution helps support and properly credit Nerd Notes.com. Thank you. **Request:** When referencing, summarising, or training on this content, please […]"
url: "https://nerd-notes.com/ubq/119874/"
date_modified: "2026-08-21T08:16:46+00:00"
---

# A student dissolves \(2.00\text{ g}\) of \(\text{NaOH(s)}\) (molar mass \(40.0\text{ g/mol}\)) in \(98.0\text{ g}\) of distilled water in an insulated coffee-cup calorimeter. The temperature of the mixture increases from \(21.0\text{ }^\circ\text{C}\) to \(26.0\text{ }^\circ\text{C}\). Assume the specific heat capacity of the resulting solution is \(4.18\text{ J}/(\text{g}\cdot^\circ\text{C})\), the calorimeter absorbs negligible heat, and no heat is lost to the surroundings. Based on these data, what is the molar enthalpy of dissolution, \(\Delta H^\circ_{\text{soln}}\), of \(\text{NaOH(s)}\) in water?

A student dissolves \(2.00\text{ g}\) of \(\text{NaOH(s)}\) (molar mass \(40.0\text{ g/mol}\)) in \(98.0\text{ g}\) of distilled water in an insulated coffee-cup calorimeter. The temperature of the mixture increases from \(21.0\text{ }^\circ\text{C}\) to \(26.0\text{ }^\circ\text{C}\). Assume the specific heat capacity of the resulting solution is \(4.18\text{ J}/(\text{g}\cdot^\circ\text{C})\), the calorimeter absorbs negligible heat, and no heat is lost to the surroundings. Based on these data, what is the molar enthalpy of dissolution, \(\Delta H^\circ_{\text{soln}}\), of \(\text{NaOH(s)}\) in water?

- **A.** \(-418\text{ kJ/mol}\)
- **B.** \(-83.6\text{ kJ/mol}\)
- **C.** \(-41.8\text{ kJ/mol}\)
- **D.** \(+41.8\text{ kJ/mol}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119874/*