when companies sell compressed gas in steel cylinders, they usually quote the contents as volume of gas at 1 atm pressure at tempertaure of 20...

when companies sell compressed gas in steel cylinders, they usually quote the contents as volume of gas at 1 atm pressure at tempertaure of 20 degrees celcius. One such company sells cylinders said to contain 7 meters cubed of helium. The pressure in the cylinder is 15.5Mpa and interneal volume is 46.9L. Find the moles of helium gas in the cylinder