Chem 120 / Dr. Rusay

Energy Absorbance


Lab & Webshop: Greenhouse Gases II
Energy Absorbance, Infrared Spectroscopy, Molecular Motion, Vibrational Energies

Image above: Visible light being absorbed by the earth's atmosphere

Energy / Sunlight / EM Spectrum / Infrared / Ultraviolet / Greenhouse Gases

Refer to the course Lab Manual pg.27:

1) Complete tables with a list of the respective frequencies (wavenumber, cm-1) of the major infrared (IR) absorbances and their corresponding percent transmission in the spectrum for your assigned greenhouse gases. (Check in lab for gas assignments) Consult the following: Ohio State University: Infrared Spectroscopy,, ChemConnections, MC2/Chemlinks and NIST WebBook pages:

2) Refer to the Ohio State University tutorial on Infrared Spectroscopy: View the IR spectra of your assigned greenhouse gases. For each of the absorbances (peaks) in each of the assigned gases in #1, list the type of molecular vibration that you believe to correspond to the absorbance in the spectrum. Eg. bending or stretching vibration. If possible identify the vibration as symmetrical or anti-symmetrical.

Complete the questions on the Webshop: Greenhouse Gases II form

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