Assume that a round bottom flask holds 100 mL and the distilling head has an internal volume of 12 mL in the vertical section. At the end of a distillation, vapor would fill this volume, but it could not be forced through the system. No liquid would remain in the distillation flask. Assuming this holdup volume of 112 mL, use the ideal gas law and assume a boiling point of 100°C (760 mm Hg) to calculate the number of milliliters of liquid (0.9 g/mL, MW=200) that would recondense into the distillation flask upon cooling.

2 answers

What's the volume? Is it 12 mL or 112 mL.
If 12 mL, then
PV = nRT
You know P, V, R, and T, solve for n
Then n = grams/molar mass and solve for grams. Convert mass to volume using density.
Ok so volume would be 112 mL. Since it says that at the end of the distillation no liquid remains in the flask and vapor would fill this volume. So I assume that by 'this volume' they mean 112 mL and not just 12 mL. Am I on the right track ?