---
title: "A student is determining the standard enthalpy of reaction, \\(\\Delta H_{\\text{rxn}}^\\circ\\), for the complete combustion of liquid ethanol at \\(298\\text{ K}\\) and \\(1\\text{ atm}\\) represented by the balanced equation below.  \\[ \\text{C}_2\\text{H}_5\\text{OH}(l) + 3\\,\\text{O}_2(g) \\rightarrow 2\\,\\text{CO}_2(g) + 3\\,\\text{H}_2\\text{O}(l) \\]  Which of the following substances in the reaction has a standard enthalpy of formation, \\(\\Delta H_f^\\circ\\), equal to \\(0\\text{ kJ/mol}\\) at \\(298\\text{ K}\\) and \\(1\\text{ atm}\\)?"
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url: "https://nerd-notes.com/ubq/119670/"
date_modified: "2026-08-21T08:12:00+00:00"
---

# A student is determining the standard enthalpy of reaction, \(\Delta H_{\text{rxn}}^\circ\), for the complete combustion of liquid ethanol at \(298\text{ K}\) and \(1\text{ atm}\) represented by the balanced equation below.

\[ \text{C}_2\text{H}_5\text{OH}(l) + 3\,\text{O}_2(g) \rightarrow 2\,\text{CO}_2(g) + 3\,\text{H}_2\text{O}(l) \]

Which of the following substances in the reaction has a standard enthalpy of formation, \(\Delta H_f^\circ\), equal to \(0\text{ kJ/mol}\) at \(298\text{ K}\) and \(1\text{ atm}\)?

A student is determining the standard enthalpy of reaction, \(\Delta H_{\text{rxn}}^\circ\), for the complete combustion of liquid ethanol at \(298\text{ K}\) and \(1\text{ atm}\) represented by the balanced equation below.

\[ \text{C}_2\text{H}_5\text{OH}(l) + 3\,\text{O}_2(g) \rightarrow 2\,\text{CO}_2(g) + 3\,\text{H}_2\text{O}(l) \]

Which of the following substances in the reaction has a standard enthalpy of formation, \(\Delta H_f^\circ\), equal to \(0\text{ kJ/mol}\) at \(298\text{ K}\) and \(1\text{ atm}\)?

- **A.** \(\text{CO}_2(g)\)
- **B.** \(\text{H}_2\text{O}(l)\)
- **C.** \(\text{O}_2(g)\)
- **D.** \(\text{C}_2\text{H}_5\text{OH}(l)\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119670/*