Question

A cylinder of oxygen has a gauge pressure of 2000psi and a volume of 16L at 70 degrees F. If the oxygen is used as a constant flow rate of 2 L/minute, measured at 1 atm of pressure, how long will the tank last? Hint: Calculate the mass (grams) of oxygen in the tank and the mass flow rate (number of grams/min) flowing out the tank at 1 atm of pressure.