I think this is the problem. My OA does seem to be a little more "wet." I bought a lot from Chemistrystore. So, it just needed more than what I weighed, which makes a sense.

So how about %? How can I figure this out?

Thanks again.


Quote Originally Posted by Michael Mutmansky
I think that the problem is that oxalic acid can be hydrated, or it could be somewhat dehydrated (it will hold 2 water molecules per oxalic molecule). If the oxalic is not fully hydrated, it will be more potent per given mass, and vice versa.