> ...The gas law formula is PV=nRT so V (volume) = n (avogadro's > number, 6.02 x 10 to the 23) x R (molecular weight, or weight of one > mole ... Exactly. I was hoping someone had those figures at hand and would find the problem trivial. It isn't for me, nor does it appear important enough to spend much time on it. More below. > But the temperature to use for the calculation is problematic. I > would suggest that you use the melting point of oxalic acid... This is the question. To my mind, if the acid and the water sublimate, at some moment, the volume would be at the temperature of vapourization give or take, In current practice, though, I doubt the entire volume of gas ever endures. My interest in that volume, for the OA PLUS the water of hydration is merely that I assume that, at some moment in time, the OA and water expand into gas and wondering about accommodating that volume at vaporization temperature or slightly above, say in a balloon which would subsequently be deflated into an air stream. How big would the balloon have to be to hold 2g of OA dihydrate vapour? (Idle dreaming...) From casual observation using current devices, since the vapour is immediately intermixed with air at the ambient temperature, I assume that the gaseous phase must not last more than an instant. The first OA to sublimate is apparently condensed and solidified again before the last OA in the vessel has been sublimated. In the process of reaching sublimation temperature for the OA, the OA and the water of hydration part their ways, or do they? Has anyone really analyzed what happens? Do they recombine immediately on re-solidification or before? The suggestions I have read are that the purpose of sublimating the acid is to create a mist of fine particles which coat the hive interior. How these fine OA particles disable the varroa is not well described, but suggestions are that it affects their feet. Other suggestions are that the varroa have more moist exteriors than bees and are therefore more vulnerable to OA than bees which are dry on the exterior. We have observed bees running around acting normal when entirely coated with OA dust. (We do not know their eventual fate). OA is pretty much harmless to human skin unless moistened, at which point it becomes very corrosive. I figure that understanding what is happening in a practical process that obviously works could help isolate the factors which make it work and potentially allow us to eliminate the unnecessary aspects. It is entirely possible in my mind that distributing a fine OA powder though out a hive is the actual actor and that the sublimation and all that heavy gear associated with the heating and blowing could be unnecessary. If a fine, fine dust could be created otherwise, distribution into hives could be as simple as using a pulse of compressed air or propane from a bottle, and all the clunky, expensive gear now used could be scrapped. *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html Guidelines for posting to BEE-L can be found at: http://honeybeeworld.com/bee-l/guidelines.htm