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Weigh solids in fume hood? - (Jul/24/2007 )

Do you guys commonly weigh solids in fume hoods on on the bench when making solutions? Solids like:

Potassium Phosphate Dibasic
Sodium Nitrate
Calcium Chloride
Potassium Chloride
Citric Acid
Ferric Ammonium Citrate
Copper Sulfate Pentahydrate

Just trying to get an idea of what is commonly done, it's hard to figure out what is actually necessary from the MSDS.

I also find it's hard to reliably weigh things in the fume hood, probably because of the air turbulence. Using an analytical balance that has an air enclosure might help, but is this overkill?


I donot weigh any solid in the fume hood. I tried with PFA but wasnt satisfied so everything is out in the open.


None of the above needs to be weighted in the hood. When I have to deal with toxic substance, I pre-weight the 50 ml centrifuge tube, load chemicals inside the tube, weight the tube and calculate how much solution to make based on the weight. Except dispensing the chemical in the hood, I do weighting outside.


no, outside is just fine.



none of the above product...
I would take care for SDS as it's irritating (but you gonna experience it if some raise in the air biggrin.gif, not dangerous but not nice too).
I consider that for exotic compounds like NaN3 for ex, extra care is better than in fume hood as fume hood raise the dispersion of compound. The mask is a good protection enough.


perfectly fine to weigh them in the open.

However, as already mentioned, you need to take care with the SDS powder. It can be suspended into the air, and breathing in the floating particles is not nice. ie getting soap up your nose.