Determine the pressure at equilibrium? Describe the total mass of chloroform in the flask? What fraction is in the vapor phase at equilibrium if a quantity of liquid chloroform is placed in an open, transparent, three liter flask and boiled long enough to purge all air from the vapor space? The flask is then sealed and allowed to equilibrate at 30 degrees Celsius, at which temperature chloroform has a vapor pressure of 243 mm Hg. Visual inspection shows 10mL of liquid chloroform present.