---
title: "Calcium oxide reacts with water according to the following thermochemical equation:  \\[ \\text{CaO}(s) + \\text{H}_2\\text{O}(l) \\rightarrow \\text{Ca(OH)}_2(s) \\quad \\Delta H^\\circ = -64.0 \\text{ kJ/mol}_{\\text{rxn}} \\]  A student adds a \\(14.0 \\text{ g}\\) sample of \\(\\text{CaO}(s)\\) (molar mass \\(56.0 \\text{ g/mol}\\)) to an excess of water at \\(25^\\circ\\text{C}\\). What is the enthalpy change, \\(\\Delta H\\), for this process?"
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url: "https://nerd-notes.com/ubq/119878/"
date_modified: "2026-08-21T08:16:53+00:00"
---

# Calcium oxide reacts with water according to the following thermochemical equation:

\[ \text{CaO}(s) + \text{H}_2\text{O}(l) \rightarrow \text{Ca(OH)}_2(s) \quad \Delta H^\circ = -64.0 \text{ kJ/mol}_{\text{rxn}} \]

A student adds a \(14.0 \text{ g}\) sample of \(\text{CaO}(s)\) (molar mass \(56.0 \text{ g/mol}\)) to an excess of water at \(25^\circ\text{C}\). What is the enthalpy change, \(\Delta H\), for this process?

Calcium oxide reacts with water according to the following thermochemical equation:

\[ \text{CaO}(s) + \text{H}_2\text{O}(l) \rightarrow \text{Ca(OH)}_2(s) \quad \Delta H^\circ = -64.0 \text{ kJ/mol}_{\text{rxn}} \]

A student adds a \(14.0 \text{ g}\) sample of \(\text{CaO}(s)\) (molar mass \(56.0 \text{ g/mol}\)) to an excess of water at \(25^\circ\text{C}\). What is the enthalpy change, \(\Delta H\), for this process?

- **A.** \(-64.0 \text{ kJ}\)
- **B.** \(-16.0 \text{ kJ}\)
- **C.** \(+16.0 \text{ kJ}\)
- **D.** \(+64.0 \text{ kJ}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119878/*