A balloon initially contains 40 m3 of helium gas at atmospheric conditions of 100 kPa and 17C. The balloon is connected by a valve to a large reservoir that supplies helium gas at 125 kPa and 25 C. Now the valve is opened, and helium is allowed to enter the balloon until pressure equilibrium with the helium at the supply line is reached. The material of the balloon is such that its volume is directly proportional to its pressure. If no heat transfer takes place during this process, determine the final temperature in the balloon. T = 25C P, = 125 kPa He P= 100 kPa T= 17C