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title: "The reaction energy profile for the gas-phase reaction \\(\\text{CO(g)} + \\text{NO}_2\\text{(g)} \\rightarrow \\text{CO}_2\\text{(g)} + \\text{NO(g)}\\) is shown in the diagram. Which of the following correctly identifies the activation energy, \\(E_a\\), for the forward reaction and the enthalpy change, \\(\\Delta H^\\circ_{\\text{rxn}}\\), for the reaction?"
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url: "https://nerd-notes.com/ubq/119729/"
date_modified: "2026-08-21T08:12:10+00:00"
---

# The reaction energy profile for the gas-phase reaction \(\text{CO(g)} + \text{NO}_2\text{(g)} \rightarrow \text{CO}_2\text{(g)} + \text{NO(g)}\) is shown in the diagram. Which of the following correctly identifies the activation energy, \(E_a\), for the forward reaction and the enthalpy change, \(\Delta H^\circ_{\text{rxn}}\), for the reaction?

The reaction energy profile for the gas-phase reaction \(\text{CO(g)} + \text{NO}_2\text{(g)} \rightarrow \text{CO}_2\text{(g)} + \text{NO(g)}\) is shown in the diagram. Which of the following correctly identifies the activation energy, \(E_a\), for the forward reaction and the enthalpy change, \(\Delta H^\circ_{\text{rxn}}\), for the reaction?

![A grayscale reaction energy profile on bare perpendicular coordinate axes. The vertical axis is labeled Potential Energy (kJ/mol_rxn) with three numerical tick marks at 50, 130, and 260. Thin horizontal dashed reference lines extend rightward across the plot from each of these three values. The horizontal axis is labeled Reaction Progress with no numerical values. A single smooth solid black curve begins at a horizontal plateau at energy value 130, labeled with the text CO(g) + NO2(g) directly above the line. The curve rises to a single rounded maximum at energy value 260, then descends smoothly to a lower horizontal plateau at energy value 50, labeled with the text CO2(g) + NO(g) directly above the line. No other curves, labels, text, or annotations appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787299930-c99bNa.jpg)

- **A.** \(E_a = 130\text{ kJ/mol}_{\text{rxn}}\); \(\Delta H^\circ_{\text{rxn}} = -80\text{ kJ/mol}_{\text{rxn}}\)
- **B.** \(E_a = 130\text{ kJ/mol}_{\text{rxn}}\); \(\Delta H^\circ_{\text{rxn}} = +80\text{ kJ/mol}_{\text{rxn}}\)
- **C.** \(E_a = 210\text{ kJ/mol}_{\text{rxn}}\); \(\Delta H^\circ_{\text{rxn}} = -80\text{ kJ/mol}_{\text{rxn}}\)
- **D.** \(E_a = 210\text{ kJ/mol}_{\text{rxn}}\); \(\Delta H^\circ_{\text{rxn}} = +80\text{ kJ/mol}_{\text{rxn}}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119729/*