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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: cyril on November 29, 2005, 03:55:09 PM

Title: ice photochemistry measurement
Post by: cyril on November 29, 2005, 03:55:09 PM
I am working on a research project where we would like to measure uv absorption of organic chemicals in ice.

The problem is to freeze water in a 1cm cell without broken it....which I already done...broke a quartz cell

I thaught that may be a pyrex cell will be strong enough to resist the lateral expansion of ice...if someone has any advice about this...

Thanks everybody for any help
Title: Re:ice photochemistry measurement
Post by: jumpinjackoo on December 05, 2005, 07:34:33 PM
i know this doesn't answer your your question but can i ask you how can you accelerate icing of water?
Title: Re:ice photochemistry measurement
Post by: jwesterway on December 07, 2005, 02:12:18 AM
Im presuming your putting water into the cell and freezing it?
The water will freeze on the exposed surface first, this is why air bubbles are trapped inside ice cubes, what you need to do is to place the cell in a coolant of some sort to freeze the bottom first then slowly submerge the cell to freeze from the bottom up to allow the water to expand upward to the open section of the cell during expansion due to freezing. Simply placing the water filled cell in the freezer will cause top down freezing and hence break your quartz cells, you need to make the water freeze bottom up. Try somethin like what i have described.

Title: Re:ice photochemistry measurement
Post by: lemonoman on December 07, 2005, 03:58:54 AM
"Freeze it bottom up."?  That's slick.

I guess just make sure you absolutely NEED to use quartz sense using quartz if glass/plastic would work just as well  :D

And like the guy before me said, the air bubble thing is always something to watch.

Best of luck  :)