volume of air under presssure compared to volume with no pressure.

I am trying to find the equation for determining the amount of air at atomasphere compared to air underpressure. In other words, I have a 1 square foot of a under pressure at 10 psi. What would the volume be if it was not under pressure, ie at atomasphere. I do realize that I would need to know the current barometric pressure.


Thankyou

[Robert Fogt]

You would use the ideal gas law.

If temperature changes as well:
(Pi * Vi) / Ti = (Pf * Vf) / Tf

Or if temperature stays constant:
Pi * Vi = Pf * Vf

P = pressure, V = volume, T = temperature
i = initial, f = final

One problem I see is that you list the volume in square foot, a volume would be a unit such as cubic foot.

Another problem I see is that 1 atmosphere = 14.6959488 psi which would make your final pressure more than your initial pressure, unless the initial pressure is gauge, which I assume it is.

Bullette at 23 kg/cm2 of pressure having 73 m3 of volume then what will be the mass of that pressure ? please reply