A block of ice of mass 0.8 kg and initial temperature T = 0 C is placed in a sealed insulated container full of Helium gas, initially at temperature 155 C and pressure of 1 atm. The volume of the Helium is 870 L, and is constant. Helium is a monatomic ideal gas.
What is the mass of the liquid water when the system comes to equilibrium? (In other words, how much ice melts?)