Chemistry 2210A/B Study Guide - Midterm Guide: Polar Stratospheric Cloud, Ozone Depletion, Vacuum Cleaner
Document Summary
Regions of electromagnetic spectrum; approximate wavelengths (especially for uv-a, b and c) Relationship between wavelength of light and the energy of its photons; how does this relate to the thermodynamics of chemical reactions. Molecules and bonds absorb at different frequencies of light. Wavelengths shorter than 120 absorbed by o2 and n2. O2 above stratosphere absorbs most uv light from 120-220 (c) O3 absorbs light in 220-290 range (all of c, very little b) Shorter the wavelength, more absorption will not reach earth. Ozone creation and destruction in the stratosphere; the chapman cycle (don"t memorize equations; just what is happening?) First reaction: o2 2o (absorb uv-c, shortest wavelength, highest energy: above stratosphere ! filters most uvc before reach strato, mostly o. Second reaction: o + o2 o3 + heat: in stratosphere, oxygen mainly molecular. Third: o3 absorbs uva o + o2. Fourth: o3 + o 2o2 (small extent, high ea) Cycle is naturally occurring during daylight hours, and occurs in stratosphere.
