A vessel holding some liquid is placed in a vacuum chamber that is constantly pumped. Gas leaks from the vessel into the vacuum through a small hole, radius 4.15 micro m, but the pressure inside the vessel remains 38.6 kPa. After a day mass of the vessel has dropped from 100 g to 99.5 g. Assuming the container has at all times been at 70 K, suggest (with reasoning) the identity of the liquid.