I'm heating water in a pressure cooker on my stove top. pressure cookers work by letting pressure inside the closed pot to a critical pressure p 3 bar at which point gas is released through a valve in the lid. when i put the water in, it's at 30 °c and 1 bar. the pressure cooker is filled completely with liquid with negligible head space, and has a volume v. i turn on the stove and come back a while later to find pot is only one-fourth full of liquid, and the rest is vapor how much mass escapes the pot during that time?