Weight of air at 100 PSI

[shawn b]

Some friends and I were moving a 30 gallon air compressor and after we moved it decided it would have been better to let the air out first. I would like to know how much more the tank weighs with it full of air at 100 PSI. Is there a simple formula to use to make this calculation?

Thanks so much for your help.
Shawn Boyers

 

[russ_watters]

Well, the density of air at sea level pressure (14.7 psi) is .075 lb/ft^3 and there are 7.46 gal/ cu ft...

 

[FredGarvin]

Ideal gas law...

 

[Q_Goest]

2 pounds