1. The problem statement, all variables and given/known data There is a vessel with 10 Liters of Liquid Nitrogen. The normal pressure is 100 Psi. After a couple hours the pressure is dropped to 47 Psi because of leak in the vessel. How much of the Liquid Nitrogen did we lose/is left in the vessel? 2. Relevant equations I'm really not sure. I thought about P1V1 = P2V2, but I don't think that will work here. 3. The attempt at a solution Using P1V1 = P2V2 I got an answer, but I think that will only work for a closed system (drop in pressure means increase in volume and vice versa) So, does anyone have an idea how to solve this?