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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: auggee on September 06, 2005, 06:37:49 AM

Title: What do you mean when you have an assay of 101?
Post by: auggee on September 06, 2005, 06:37:49 AM

Assay values of pure substances usually ranges from 99 to 101. What do you mean when you have an assay of 101?
Kindly suggest some sites/links re: assay.  Thanks. :)

Title: Re:Assay
Post by: eugenedakin on September 14, 2005, 10:18:35 PM

Hello Auggee,

I have seen this in a few situations.

It is usually the way in which a calculation has been presented... for example:

Borax is available in hydrated form (Na₂B₄O₇*10H₂O).  Sodium borate makes up 52.8% of the molecule.  When an assay is performed on a final blend (lets say 53.8%), the amount of borax decahydrate is calculated out to be 101.9%.  This calculation is under the assumption that all the borax is decahydrate.

More than likely, most of the borax is decahydrate, and some is pentahydrate, or even anhydrous.

It is not a wide practice in the field, but it does occasionally occur.

I hope this helps,

Eugene