[alt-photo] Re: "Moistened" AD (4th and final attempt)

[Christina Anderson]

From my notes, sodium dichromate is deliquescent (one of the properties said to make it harder to measure accurately) but since we are not worried about being off by a gram or two usually, I have never worried about it and don't use sodium much anyway. But I have not seen that characteristic applied to AD, is it?

But even if water were added it wouldn't affect its capacity to harden gum, as it is inert (is that the correct term?)  until it is in contact with an organic, correct, chemists?

Whatever, I've used am di in solution that was 6-12 years old with no problem (left by a former professor and or student).
Chris

Christina Z. Anderson
christinaZanderson.com

On Jan 7, 2010, at 11:46 AM, Trevor Cunningham wrote:

> 1kg of the powder is a little over $100. But the moistened is actually a little cheaper. As long as it does the same thing, I'm a happy camper. I get the impression from them that they might need to back order the crystal form. Would storage become an issue with keeping it "moist"? Or could I turn it all into solution and leave it on the shelf?
> 
> What does .5% - 3 water mean? The sheet you linked is exactly the same product, # and all.
> 
> 
> Tomas Sobota wrote:
>> Not sure why they moist the Am. dichromate (0.5% - 3 water) but this is a
>> pure reagent for analysis and it will probably be expensive. 
> 
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