---
title: "Nitrogen oxides are formed during high-temperature combustion in automobile engines. The thermochemical equations for two reactions involving nitrogen oxides are shown below.  \\[ \\text{N}_2(g) + \\text{O}_2(g) \\rightarrow 2\\text{ NO}(g) \\quad \\Delta H^\\circ = +180\\text{ kJ/mol}_{\\text{rxn}} \\] \\[ 2\\text{ NO}_2(g) \\rightarrow 2\\text{ NO}(g) + \\text{O}_2(g) \\quad \\Delta H^\\circ = +114\\text{ kJ/mol}_{\\text{rxn}} \\]  Based on the data above, what is the value of \\(\\Delta H^\\circ\\) for the reaction represented by the following equation?  \\[ \\text{N}_2(g) + 2\\text{ O}_2(g) \\rightarrow 2\\text{ NO}_2(g) \\]"
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url: "https://nerd-notes.com/ubq/119995/"
date_modified: "2026-08-21T08:31:42+00:00"
---

# Nitrogen oxides are formed during high-temperature combustion in automobile engines. The thermochemical equations for two reactions involving nitrogen oxides are shown below.

\[ \text{N}_2(g) + \text{O}_2(g) \rightarrow 2\text{ NO}(g) \quad \Delta H^\circ = +180\text{ kJ/mol}_{\text{rxn}} \]
\[ 2\text{ NO}_2(g) \rightarrow 2\text{ NO}(g) + \text{O}_2(g) \quad \Delta H^\circ = +114\text{ kJ/mol}_{\text{rxn}} \]

Based on the data above, what is the value of \(\Delta H^\circ\) for the reaction represented by the following equation?

\[ \text{N}_2(g) + 2\text{ O}_2(g) \rightarrow 2\text{ NO}_2(g) \]

Nitrogen oxides are formed during high-temperature combustion in automobile engines. The thermochemical equations for two reactions involving nitrogen oxides are shown below.

\[ \text{N}_2(g) + \text{O}_2(g) \rightarrow 2\text{ NO}(g) \quad \Delta H^\circ = +180\text{ kJ/mol}_{\text{rxn}} \]
\[ 2\text{ NO}_2(g) \rightarrow 2\text{ NO}(g) + \text{O}_2(g) \quad \Delta H^\circ = +114\text{ kJ/mol}_{\text{rxn}} \]

Based on the data above, what is the value of \(\Delta H^\circ\) for the reaction represented by the following equation?

\[ \text{N}_2(g) + 2\text{ O}_2(g) \rightarrow 2\text{ NO}_2(g) \]

- **A.** \(-294\text{ kJ/mol}_{\text{rxn}}\)
- **B.** \(-66\text{ kJ/mol}_{\text{rxn}}\)
- **C.** \(+33\text{ kJ/mol}_{\text{rxn}}\)
- **D.** \(+66\text{ kJ/mol}_{\text{rxn}}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119995/*