The vacuum flask looks like an Erlenmeyer flask with a short arm coming out of it. The "arm" is designed to connect the flask to a vacuum source. When sealed on the top with a stopper or a Buchner funnel, the vacuum flask will hold a reduced pressure. Note the heavy the walls of this flask - they are designed to withstand reduced pressure without imploding. This design feature is the reason for the high cost of this flask.
Vacuum flasks are also called "side-arm flasks" and "filtering flasks".
Vacuum flasks are used either for filtering solutions or for removing solvent under reduced pressure. You should have two vacuum flasks in your lab drawer. One is either 125 mL or 250 mL: use this larger one for filtering only. One is either 25 mL or 50 mL: use this smaller one for removing solvent under reduced pressure.
Location: student lab drawer equipment.
Cost:
small (25 mL or 50 mL): $10.00
large (125 mL or 250 mL: $10.50
