Trichloroethane, C2H3Cl3, is the active ingredient in aerosols that claim to stain-proof men's ties. Trichloroethane has a vapor pressure of 100.0 mm Hg at 20.0 C and boils at 74.1 C. An uncovered cup (1/2 pint) of trichloroethane (d=1.325 g/mL) is kept in an 18-ft3 refrigerator at 39 F. What percentage (by mass) of trichloroethane is left as a liquid when equilibrium is established?