---
title: "A student investigates the oxidation of carbon monoxide in two sealed vessels at \\(298\\ \\text{K}\\). The vessels have the same volume and initially contain the same partial pressures of \\(\\text{CO(g)}\\) and \\(\\text{O}_2\\text{(g)}\\). The reaction and its standard Gibbs free-energy change are shown below.  \\(2\\text{CO(g)}+\\text{O}_2\\text{(g)}\\rightarrow 2\\text{CO}_2\\text{(g)}\\qquad \\Delta G^\\circ_{\\mathrm{rxn}}=-514\\ \\text{kJ/mol}_{\\mathrm{rxn}}\\)  | Surface in vessel | Percentage of \\(\\text{CO(g)}\\) converted after \\(30\\ \\text{min}\\) | |—|—:| | Uncoated ceramic | Less than \\(1\\%\\) | | Palladium-coated ceramic | Approximately \\(70\\%\\) |  Which statement best explains both the sign of \\(\\Delta G^\\circ_{\\mathrm{rxn}}\\) and the difference between the results?"
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url: "https://nerd-notes.com/ubq/119485/"
date_modified: "2026-08-19T12:40:41+00:00"
---

# A student investigates the oxidation of carbon monoxide in two sealed vessels at \(298\ \text{K}\). The vessels have the same volume and initially contain the same partial pressures of \(\text{CO(g)}\) and \(\text{O}_2\text{(g)}\). The reaction and its standard Gibbs free-energy change are shown below.

\(2\text{CO(g)}+\text{O}_2\text{(g)}\rightarrow 2\text{CO}_2\text{(g)}\qquad \Delta G^\circ_{\mathrm{rxn}}=-514\ \text{kJ/mol}_{\mathrm{rxn}}\)

| Surface in vessel | Percentage of \(\text{CO(g)}\) converted after \(30\ \text{min}\) |
|—|—:|
| Uncoated ceramic | Less than \(1\%\) |
| Palladium-coated ceramic | Approximately \(70\%\) |

Which statement best explains both the sign of \(\Delta G^\circ_{\mathrm{rxn}}\) and the difference between the results?

A student investigates the oxidation of carbon monoxide in two sealed vessels at \(298\ \text{K}\). The vessels have the same volume and initially contain the same partial pressures of \(\text{CO(g)}\) and \(\text{O}_2\text{(g)}\). The reaction and its standard Gibbs free-energy change are shown below.

\(2\text{CO(g)}+\text{O}_2\text{(g)}\rightarrow 2\text{CO}_2\text{(g)}\qquad \Delta G^\circ_{\mathrm{rxn}}=-514\ \text{kJ/mol}_{\mathrm{rxn}}\)

| Surface in vessel | Percentage of \(\text{CO(g)}\) converted after \(30\ \text{min}\) |
|---|---:|
| Uncoated ceramic | Less than \(1\%\) |
| Palladium-coated ceramic | Approximately \(70\%\) |

Which statement best explains both the sign of \(\Delta G^\circ_{\mathrm{rxn}}\) and the difference between the results?

- **A.** The reaction is thermodynamically favorable under standard conditions but kinetically slow without palladium, because the large magnitude of \(\Delta G^\circ_{\mathrm{rxn}}\) causes reactants to cross the activation-energy barrier slowly.
- **B.** The reaction is thermodynamically favorable under standard conditions but kinetically slow without palladium, because \(\Delta G^\circ_{\mathrm{rxn}}<0\) indicates thermodynamic favorability, whereas the greater conversion with palladium indicates a lower-activation-energy pathway.
- **C.** The reaction is thermodynamically unfavorable under standard conditions and kinetically slow without palladium, because the small conversion after \(30\ \text{min}\) shows that the equilibrium mixture contains mostly reactants.
- **D.** The reaction is thermodynamically unfavorable under standard conditions and kinetically slow without palladium, because a high activation-energy barrier can limit reaction rate independently of thermodynamic favorability.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119485/*