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## mw of copper carb

### Wade Blocker on wed 16 feb 00

Dear Tom,
You are absolutely right, the MW of copper carb is 221.1. according to
Wolf E. Matthes "Keramische Glasuren" p.434. David Green in A Handbook of
Pottery Glazes gives the MW as 221.13. Robert Fournier in" Illustrated
Dictionary of Practical Pottery" 123.5.
The number I posted was from Cushing's Handbook CuC03 -l24. I imagine a
misprint.
Thank you for catching this mistake. My knowledge of chemistry is abysmal,
and I rely on
books for the answers. Too bad that I chose to quote the wrong reference,
at least you set the record straight Mia in ABQ.

### Jim Cullen on sat 19 feb 00

The more I read the more confused I get...

I went to CeramicSearch.com, typed in Copper Carbonate and get a RAW WEIGHT
of 79.54 and no indicated L.O.I. So I type in Copper Oxide and see the RAW
WEIGHT is 79.54????????
Is this right? And what are the 124, 123.5, 221.13, and 221.1 numbers that

Why so many different opinions? What do we use in our software programs?

Where do we go for meaningful numbers?

FRUSTRATED, but CENTERED
Cullen
Naperville, Illinois

### Dave Finkelnburg on sun 20 feb 00

Jim,
You can do the arithmetic and see for yourself which are the right
numbers.
Atomic weight of copper, Cu, is 63.54
oxygen is 16.
Add those up and you see you had the right number for CuO.
As Tom Buck has pointed out, copper carbonate is malachite,
CuCO3.Cu(OH)2. Oops, looks like you got a bad number for that, as you have
Weight of carbon is 12
Hydrogen is 1.
You can do the arithmetic.
Many sources, many folks, round off atomic weights to the nearest whole
number. Most of the differences you are citing are just due to
rounding--they're basically the same numbers, close enough for all practical
purposes.
IF you have the right chemical formula, the safest way to get the right
weight is to use a table of Atomic Weights of the Elements and do your own
arithmetic.
Good glazing!
Dave Finkelnburg
-----Original Message-----
From: Jim Cullen
To: CLAYART@LSV.UKY.EDU
Date: Saturday, February 19, 2000 6:23 PM
Subject: Re: MW of copper carb

>----------------------------Original message----------------------------
>The more I read the more confused I get...
>
>I went to CeramicSearch.com, typed in Copper Carbonate and get a RAW WEIGHT
>of 79.54 and no indicated L.O.I. So I type in Copper Oxide and see the RAW
>WEIGHT is 79.54????????
>Is this right? And what are the 124, 123.5, 221.13, and 221.1 numbers that
>
>Why so many different opinions? What do we use in our software programs?
>
>Where do we go for meaningful numbers?
>
>FRUSTRATED, but CENTERED
>Cullen
>Naperville, Illinois
>

### Jim Cullen on sun 20 feb 00

Good artists copy, great artists steal. - PICASSO

Sorry Tom, I didn't copy really...I stole.

Thanks for the info.

KEEP CENTERED
Cullen
Naperville, Illinois