a Molar mass (g/mol) Retention volume (mL) 640000 12.14 The resulting retention volumes for a series of polystyrene standards of known molar mass injected onto a gel-permeation chromatography (GPC) column are displayed in the table. A polymer sample of unknown molar mass had a retention volume of 15.41 mL under the same conditions. 483000 13.07 a 245000 14.01 118000 15.82 Calculate the molar mass of the polymer sample. 76000 17.06 23000 19.38 molar mass: g/mol