The vapor pressure of chloroform is 173.11 mm Hg at 25°C. How many grams of estrogen (estradiol), C₁₈H₂₄O₂, a nonvolatile, nonelectrolyte (MW = 272.4 g/mol), must be added to 235.2 grams of chloroform to reduce the vapor pressure to 170.72 mm Hg ? chloroform = CHCl₃= 119.40 g/mol.