---
title: "An atmospheric chemist uses infrared (	ext{IR}) spectroscopy to analyze gas emissions containing 	ext{H}_2	ext{O(g)} and 	ext{SO}_2	ext{(g)} collected near a volcanic vent. Which of the following correctly identifies the microscopic change that occurs when these molecules absorb 	ext{IR} radiation and provides the valid justification?"
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url: "https://nerd-notes.com/ubq/123617/"
date_modified: "2026-09-28T12:01:47+00:00"
---

# An atmospheric chemist uses infrared (	ext{IR}) spectroscopy to analyze gas emissions containing 	ext{H}_2	ext{O(g)} and 	ext{SO}_2	ext{(g)} collected near a volcanic vent. Which of the following correctly identifies the microscopic change that occurs when these molecules absorb 	ext{IR} radiation and provides the valid justification?

An atmospheric chemist uses infrared (	ext{IR}) spectroscopy to analyze gas emissions containing 	ext{H}_2	ext{O(g)} and 	ext{SO}_2	ext{(g)} collected near a volcanic vent. Which of the following correctly identifies the microscopic change that occurs when these molecules absorb 	ext{IR} radiation and provides the valid justification?

- **A.** Transitions between vibrational energy levels occur because the energy of 	ext{IR} photons matches the energy differences associated with changes in molecular bond stretching and bending.
- **B.** Transitions between rotational energy levels occur because 	ext{IR} photons have lower energy than microwave photons and therefore can only induce whole-molecule rotation.
- **C.** Transitions between electronic energy levels occur because the energy of 	ext{IR} photons is sufficient to excite valence electrons to higher unoccupied molecular orbitals.
- **D.** Transitions between vibrational energy levels occur because the absorbed 	ext{IR} photons eject core electrons, causing temporary distortion and vibration of the chemical bonds.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123617/*