chemistry
posted by Jess .
How many moles of gas must be forced into a 3.1L ball to give it a gauge pressure of 9.8psi at 22degrees C? The gauge pressure is relative to atmospheric pressure. Assume that atmospheric pressure is 14.5psi so that the total pressure in the ball is 24.3psi .

Convert 24.3 psi to atm and use PV = nRT, then solve for n.
24.3 psi is approximately 1.65 atm. Remember T must be in kelvin.