---
title: "A student investigates the hydrogenation of ethene to form ethane, represented by the balanced equation below:  \\(\\text{C}_2\\text{H}_4\\text{(g)} + \\text{H}_2\\text{(g)} \\rightarrow \\text{C}_2\\text{H}_6\\text{(g)}\\)  | Bond | Average Bond Enthalpy (kJ/mol) | |—|—| | \\(\\text{C–C}\\) | 348 | | \\(\\text{C=C}\\) | 614 | | \\(\\text{C–H}\\) | 413 | | \\(\\text{H–H}\\) | 436 |  Based on the average bond enthalpies given in the table, what is the estimated standard enthalpy change, \\(\\Delta H^\\circ_{rxn}\\), for the reaction?"
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url: "https://nerd-notes.com/ubq/119343/"
date_modified: "2026-08-19T12:39:53+00:00"
---

# A student investigates the hydrogenation of ethene to form ethane, represented by the balanced equation below:

\(\text{C}_2\text{H}_4\text{(g)} + \text{H}_2\text{(g)} \rightarrow \text{C}_2\text{H}_6\text{(g)}\)

| Bond | Average Bond Enthalpy (kJ/mol) |
|—|—|
| \(\text{C–C}\) | 348 |
| \(\text{C=C}\) | 614 |
| \(\text{C–H}\) | 413 |
| \(\text{H–H}\) | 436 |

Based on the average bond enthalpies given in the table, what is the estimated standard enthalpy change, \(\Delta H^\circ_{rxn}\), for the reaction?

A student investigates the hydrogenation of ethene to form ethane, represented by the balanced equation below:

\(\text{C}_2\text{H}_4\text{(g)} + \text{H}_2\text{(g)} \rightarrow \text{C}_2\text{H}_6\text{(g)}\)

| Bond | Average Bond Enthalpy (kJ/mol) |
|---|---|
| \(\text{C–C}\) | 348 |
| \(\text{C=C}\) | 614 |
| \(\text{C–H}\) | 413 |
| \(\text{H–H}\) | 436 |

Based on the average bond enthalpies given in the table, what is the estimated standard enthalpy change, \(\Delta H^\circ_{rxn}\), for the reaction?

- **A.** \(-560 \text{ kJ/mol}\)
- **B.** \(-390 \text{ kJ/mol}\)
- **C.** \(-124 \text{ kJ/mol}\)
- **D.** \(+124 \text{ kJ/mol}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119343/*