A 0.90g sample of liquid water was introduced into an evacuated 2.00 L flask, which was then sealed and heated to 37 (degree)C. What percentage, by mass, of the water remained as liquid? [Vapor pressure of water at 37 (degree)C=48.2 torr]

Answer 1

mass of water vapor:

n=PV/RT caculate n using P=vapor pressure.
change moles (n) to grams.

subtract that from the original mass of water, then you have it.