A balloon in the upper atmosphere is filled with water vapor with a speci?c volume of 10 m3 /kg. a) If its volume is 25 m3, how many moles of water vapor are in the balloon? b) The pressure inside the balloon is 0.2 bar. A process keeps the mass and pressure constant inside the balloon, but the specific volume increases to 11 m3 /kg. Show this process on a p-V diagram. c) How much work, in kJ, does the balloon perform?