Submitted by Anonymous on Tue, 12/11/2007 - 20:57

from my understanding of ozone, when O2 is hit by UV light, it splits into smaller oxygen molecules which then proceed to bond to other O2 molecules making O3. However i'm wondering if i were to obtain a glass flask of O2 and shine a UV light onto it,

1. would the O2 in the flask all be converted to O3, or does the O3 break back down into O2 and O1 upon contact with UV light again?

2. if i were to place a UV sensor or photometer on the other side of the flask, how would my readings be different when the UV light is shining through the O2 gas than from when there is nothing in between the UV light source and the photometer?

chris,

a chemistry student

Elke Bergholz

Dear Chris, Thank you for your questions.1. Reagarding your bottle experiemt with O2 inside and the UV light shining on it: I have never made any maesurements like that. I know that O2 is split be the UV light and hen O2 combines with a single O atom to form ozone, as you described correctly. If UV light continues to be available, the depletion and formation of O3 should continue as it does in the Stratosphere. Within a close sytem like a close bottle, it would be hard to test the O3 production. Also, depending on the glass, UV light might not pepnetrate. It would depend what UV light you are using. I would encourage you to try. Set a good prediction before you start. Let me know if you succeed. It would be an intersting development of a method for  a research project.2.  I am not certain what you mean with this. The set up is not clear to me. I am assuming you mean: a) you measure the UV light on the other side of the glass or b) you measure the UV right in front of he UV source without the bottle in between. I would think the reading would depend on the material/bottle in between. Some studnets tested the UV going through different material. Some of the hiking clothing is tested like that to let us know that we can be protected by it or not.
I advise you again to test and see for yourself. Again start with a prediction and then see if you can prove it or not.
 
Elke Bergholz