Sil Horwitz (silh@iag.net)
Wed, 10 Mar 1999 22:38:00 -0500
At 99/03/10 05:55 PM -0500, Judy wrote:
>
>At $147/lb, that's not quite $9 /ounce, or 30 cents a gram (did I figure
>that right -- $9 divided by 29???). Then wouldn't the silver oxide amount
>to a greater weight than the silver nitrate you started with, because
>oxide is *added*? Or does oxidizing take away weight? (I had chemistry in
>the 10th grade, & they hardly had the periodic table then. )
Ag (silver) has an atomic weight of 107, O (oxygen) is 16, and N (nitrogen) is
12. The total weight, then, of AgNO3 (that's a sub 3, meaning 3 oxygens) is 107
+ 12 + 48, or 167. Ag2O is 2 x 107 or 214 + 16 or a total of 230. But - as you
need two of the silver nitrate molecules to make one of the oxide, the
precipitate will have a relative weight of 115. In total you will have less
oxide. Incidently, the other results of this reaction are sodium nitrate and
water. The sodium nitrate is so stable, you won't get any decomposition into
nitrous or nitric oxides (the dangerous gases that have been mentioned - as
though nitrous oxide weren't "laughing gas" used by dentists as an anesthetic
though it is).
Incidently, silver oxide is light sensitive in that it decomposes in sunlight.
The compound called silver oxide that is used in batteries is really silver
peroxide, which is not the same thing as the oxide, and is dangerous to handle.
Silver oxide is used in the glass industry, so perhaps someone can find out
where they get it!
Sil Horwitz, FPSA
Technical Editor, PSA Journal
silh@iag.net
Visit http://www.psa-photo.org/
Personal page: http://www.iag.net/~silh/
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