Physical Chemistry: Thermodynamics, Structure, and Change

Published by W. H. Freeman
ISBN 10: 1429290196
ISBN 13: 978-1-42929-019-7

Foundations - Topic C - Waves - Exercises - Page 25: C.2(b)

Answer

Wavelength: $2.78$ $\mu m$ Frequency: $1.08\times 10^{14}$ $Hz$

Work Step by Step

The relation between wavenumber $(\tilde v)$ and wavelength $(\lambda)$ is given by $\tilde v=\frac{1}{\lambda}$ ...............$(1)$ And the relation between wavelength $(\lambda)$ and frequency $(v)$ is given by $V=v\lambda$ or, $v=\frac{V}{\lambda}$ ...................$(2)$ where $V$ is the speed of the wave. The wavenumber of a typical vibrational transition of a $O-H$ bond is given $\tilde v=3600$ $cm^{−1}$ Using eq. $1$, we find the corresponding wavelength: $\lambda=\frac{1}{\tilde v}$ or, $\lambda=\frac{1}{3600}$ $cm$ or, $\lambda\approx 2.78\times 10^{-4}$ $cm$ or, $\lambda=2.78\times 10^{-6}$ $m$ or, $\lambda=2.78$ $\mu m$ The wavelength $\lambda=2.78$ $\mu m$ corresponds to the wave in near-infrared region. The speed of near-infrared wave is equals to the speed of light in vacuum. Thus, $V=3\times 10^{8}$ $m/s$ Now, using eq. $2$, we find the corresponding frequency: $v=\frac{3\times 10^{8}}{2.78\times 10^{-6}}$ $v\approx 1.08\times 10^{14}$ $Hz$ $\therefore$ The wavelength and frequency of a typical vibrational transition of a $O-H$ bond are $2.78$ $\mu m$ and $1.08\times 10^{14}$ $Hz$ respectively.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.