A sealed, evacuated 3.11 liter container initially contains 0.87 liter of liquid helium. As the contents of the container come into thermal equilibrium with the surroundings, the liquid helium vaporizes and turns into gas. If the temperature of the laboratory is 24.8°C, what is the pressure of the helium gas inside the container? (Note: The density of liquid helium is 122.1 kg/m3.)
Truthfully I dont have any idea on how to set this up. Any help at all would be thankful.