1 / 11

CHEM 304 - 2/15/ 12

CHEM 304 - 2/15/ 12. I.C Strat . Chemistry: Catalytic Ozone Depletion - Catalyst “Families” ( HO x , NO x , ClO x ) - Reaction Paths/Cycles (#1, #2, #3) - Sources of HO x , NO x , ClO x Web updated today (HW #3, #4, and O 3 key) QUIZ M on see – email/web for scope.

corby
Télécharger la présentation

CHEM 304 - 2/15/ 12

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CHEM 304 - 2/15/12 I.C Strat. Chemistry: Catalytic Ozone Depletion - Catalyst “Families” (HOx, NOx, ClOx) - Reaction Paths/Cycles (#1, #2, #3) - Sources of HOx, NOx, ClOx Web updated today (HW #3, #4, and O3 key) QUIZ M on see – email/web for scope.

  2. 3 Main (1 + additional) Catalytic Families: “HOx”: H, OH, HO2 “NOx”: NO, NO2, (NO3- technically not included) “ClOx”: Cl, ClO, (ClO2) “BrOx”: Br, BrO, (BrO2- ? May not exist ? )

  3. NO + O3 —> NO2 + O2 NO2 + O3 —> NO + O2 Write a 2-reaction path 1 cycle w/ X=NO.

  4. NO + O3 —> NO2 + O2 NO2 + hn —> NO + O Write a 2-reaction path 2 “null” cycle w/ X=NO.

  5. HO + O3 —> HO2 + O2 HO2+ O3 —> HO + O2 Write a 2-reaction path 3 cycle w/ X=OH.

  6. Some lingo regarding “Trace species” (e.g. pollutants, reactive substances, etc.) Source: reaction or process that release trace compound. Sink: Reaction or process that “permanently” removes trace compound. Reservoir: An entity (process, substance, physical feature) that temporarily holds a trace substance

  7. Catalyst Sources: Substance must be resilient to these key (tropospheric) loss processes. • Wet Deposition or “rain out”: Is it H2O Soluble? • Reaction w/ OH: Does it have an H? • Photochemistry: Does it absorb >300nm?

  8. Absorption spectra of CFC’s

  9. Vertical Distribution of CFC’s…

  10. Lifetimes of CFC’s and related compounds this graphic does not work

  11. A real world question: How might you modify the structure of a CFC to yet reduce its contribution to stratospheric ClOx, yet retain, as much as possible, its physical properties? (Hint: How would you keep it out of the stratosphere …)

More Related