---
title: "A student compiling thermochemical reference data for a materials study considers the following processes at \\(298\\text{ K}\\) and \\(1\\text{ bar}\\). Which equation represents a standard formation process for which \\(\\Delta H_f^\\circ\\) is zero by definition?"
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date_modified: "2026-08-19T12:40:11+00:00"
---

# A student compiling thermochemical reference data for a materials study considers the following processes at \(298\text{ K}\) and \(1\text{ bar}\). Which equation represents a standard formation process for which \(\Delta H_f^\circ\) is zero by definition?

A student compiling thermochemical reference data for a materials study considers the following processes at \(298\text{ K}\) and \(1\text{ bar}\). Which equation represents a standard formation process for which \(\Delta H_f^\circ\) is zero by definition?

- **A.** \(\text{Br}_2\text{(g)} \rightarrow \text{Br}_2\text{(l)}\)
- **B.** \(\text{C(s, graphite)} \rightarrow \text{C(s, diamond)}\)
- **C.** \(\dfrac{1}{2}\text{N}_2\text{(g)}+\dfrac{3}{2}\text{H}_2\text{(g)} \rightarrow \text{NH}_3\text{(g)}\)
- **D.** \(\text{Br}_2\text{(l)} \rightarrow \text{Br}_2\text{(l)}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119409/*