---
title: "A student investigates the thermochemistry of ethanol, \\(\\text{C}_2\\text{H}_5\\text{OH}(l)\\), by analyzing its combustion reaction under standard conditions according to 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) \\quad \\Delta H_{\\text{comb}}^\\circ = -1370\\text{ kJ/mol}_{\\text{rxn}} \\]  The student compiles standard enthalpies of formation in the table below.  | Substance | State | \\(\\Delta H_f^\\circ\\ (\\text{kJ/mol})\\) | | :— | :—: | :—: | | \\(\\text{CO}_2(g)\\) | Gas | \\(-390\\) | | \\(\\text{H}_2\\text{O}(l)\\) | Liquid | \\(-290\\) | | \\(\\text{O}_2(g)\\) | Gas | \\(0\\) |  Based on the balanced equation and the data in the table, what is the standard enthalpy of formation, \\(\\Delta H_f^\\circ\\), of \\(\\text{C}_2\\text{H}_5\\text{OH}(l)\\)?"
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url: "https://nerd-notes.com/ubq/123832/"
date_modified: "2026-09-28T12:30:29+00:00"
---

# A student investigates the thermochemistry of ethanol, \(\text{C}_2\text{H}_5\text{OH}(l)\), by analyzing its combustion reaction under standard conditions according to the balanced equation below:

\[ \text{C}_2\text{H}_5\text{OH}(l) + 3\,\text{O}_2(g) \rightarrow 2\,\text{CO}_2(g) + 3\,\text{H}_2\text{O}(l) \quad \Delta H_{\text{comb}}^\circ = -1370\text{ kJ/mol}_{\text{rxn}} \]

The student compiles standard enthalpies of formation in the table below.

| Substance | State | \(\Delta H_f^\circ\ (\text{kJ/mol})\) |
| :— | :—: | :—: |
| \(\text{CO}_2(g)\) | Gas | \(-390\) |
| \(\text{H}_2\text{O}(l)\) | Liquid | \(-290\) |
| \(\text{O}_2(g)\) | Gas | \(0\) |

Based on the balanced equation and the data in the table, what is the standard enthalpy of formation, \(\Delta H_f^\circ\), of \(\text{C}_2\text{H}_5\text{OH}(l)\)?

A student investigates the thermochemistry of ethanol, \(\text{C}_2\text{H}_5\text{OH}(l)\), by analyzing its combustion reaction under standard conditions according to the balanced equation below:

\[ \text{C}_2\text{H}_5\text{OH}(l) + 3\,\text{O}_2(g) \rightarrow 2\,\text{CO}_2(g) + 3\,\text{H}_2\text{O}(l) \quad \Delta H_{\text{comb}}^\circ = -1370\text{ kJ/mol}_{\text{rxn}} \]

The student compiles standard enthalpies of formation in the table below.

| Substance | State | \(\Delta H_f^\circ\ (\text{kJ/mol})\) |
| :--- | :---: | :---: |
| \(\text{CO}_2(g)\) | Gas | \(-390\) |
| \(\text{H}_2\text{O}(l)\) | Liquid | \(-290\) |
| \(\text{O}_2(g)\) | Gas | \(0\) |

Based on the balanced equation and the data in the table, what is the standard enthalpy of formation, \(\Delta H_f^\circ\), of \(\text{C}_2\text{H}_5\text{OH}(l)\)?

- **A.** \(-3020\text{ kJ/mol}\)
- **B.** \(-2050\text{ kJ/mol}\)
- **C.** \(-1650\text{ kJ/mol}\)
- **D.** \(-280\text{ kJ/mol}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123832/*