---
title: "A materials scientist investigates the thermal desorption of hydrogen from a hypothetical metal hydride according to the following process.  \\(\\text{MH}_2\\text{(s)} \\rightarrow \\text{M(s)} + \\text{H}_2\\text{(g)}\\)  | Thermodynamic quantity | Value | |————————|——-| | \\(\\Delta H^\\circ\\) | \\(+75.0\\ \\text{kJ/mol}\\) | | \\(\\Delta S^\\circ\\) | \\(+150\\ \\text{J/(mol·K)}\\) |  Assume that \\(\\Delta H^\\circ\\) and \\(\\Delta S^\\circ\\) do not vary with temperature. What is the temperature threshold, in degrees Celsius, above which the process is thermodynamically favorable under standard-state conditions?"
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url: "https://nerd-notes.com/ubq/119467/"
date_modified: "2026-08-19T12:40:35+00:00"
---

# A materials scientist investigates the thermal desorption of hydrogen from a hypothetical metal hydride according to the following process.

\(\text{MH}_2\text{(s)} \rightarrow \text{M(s)} + \text{H}_2\text{(g)}\)

| Thermodynamic quantity | Value |
|————————|——-|
| \(\Delta H^\circ\) | \(+75.0\ \text{kJ/mol}\) |
| \(\Delta S^\circ\) | \(+150\ \text{J/(mol·K)}\) |

Assume that \(\Delta H^\circ\) and \(\Delta S^\circ\) do not vary with temperature. What is the temperature threshold, in degrees Celsius, above which the process is thermodynamically favorable under standard-state conditions?

A materials scientist investigates the thermal desorption of hydrogen from a hypothetical metal hydride according to the following process.

\(\text{MH}_2\text{(s)} \rightarrow \text{M(s)} + \text{H}_2\text{(g)}\)

| Thermodynamic quantity | Value |
|------------------------|-------|
| \(\Delta H^\circ\) | \(+75.0\ \text{kJ/mol}\) |
| \(\Delta S^\circ\) | \(+150\ \text{J/(mol·K)}\) |

Assume that \(\Delta H^\circ\) and \(\Delta S^\circ\) do not vary with temperature. What is the temperature threshold, in degrees Celsius, above which the process is thermodynamically favorable under standard-state conditions?

- **A.** \(-272.5^\circ\text{C}\)
- **B.** \(227^\circ\text{C}\)
- **C.** \(500^\circ\text{C}\)
- **D.** \(773^\circ\text{C}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119467/*