Answer :
Are you looking to be extremely accurate, and I'm talking atom wise?
if not it is; measure the weight and then eliminate the affect of gravity in the equation leaving you with mass
if not it is; measure the weight and then eliminate the affect of gravity in the equation leaving you with mass
Weigh the filter/container, and deposit the powder into it after recording the weight. Then, weigh the powder in the filter on a scale; subtract the container weight from the powder/container weight, and you have your mass!