Round-bottom flasks (also called round-bottomed flasks and also Erlenmeyer Bulbs) are species of flasks having actually spherical bottoms supplied as laboratory glassware, largely for chemical or biochemical work. Castle are typically made the glass because that chemical inertness; and in modern-day days, they space usually do of heat-resistant glass called Pyrex. Over there is at least one opening known as the neck. 2 or three-necked flasks are usual as well. Ring bottom flasks come in many sizes, native 5 mL to 5 L, with the sizes typically inscribed ~ above the glass. In pilot plants also larger flasks room encountered.

The ends of the necks are usually conical (female) soil glass joints. These room standardized, and can accept any type of similarly-sized tapered (male) fittings. Conventional Taper 24/40 is typical for 250 mL or bigger flasks, while smaller sizes such together 14 or 19 are used for smaller flasks.

Because that the round bottom, cork ring are necessary to keep the round bottom flasks upright. When is use, round-bottom flasks are generally held at the neck by clamps ~ above a stand.


The ring bottoms ~ above these varieties of flasks allow much more uniform heater and/or boil of liquid. Thus, round-bottom flasks are offered in a variety of applications wherein the components are cook or boiled. Round-bottom flasks space usually offered in distillation by chemists as distilling flasks and receiving flasks for the distillate (see distillation diagram). One-neck round-bottom flasks are offered as the distilling flasks in rotary evaporators.

Round-bottom flasks are often used come contain chemical reactions operation by chemists, specifically for reflux set-ups and laboratory-scale synthesis. Boil chips room often added in distilling flasks because that distillations or boiling chemical reactions to allow a nucleation site for steady boiling. This nucleation prevents a sudden boiling surge whereby the materials may overflow from the boiling flask. Stirring bars or various other stirring gadgets suited because that round-bottom flasks are periodically used. For a reflux set-up, a condenser is generally attached come the middle or only neck of the flask being used. Added necks on a flask could permit a thermometer or a mechanically stirrer come be inserted into the flask contents. The extr necks deserve to also permit a dropping funnel to it is in attached to let reactants progressively drip in.

Special electrically powered heating mantles are easily accessible in assorted sizes right into which the bottom of round-bottom flasks have the right to fit so the the components of a flask deserve to be heated because that distillation, chemistry reactions, boiling, etc. Heater can also be completed by submerging the bottom that the flask into a heat bath, water bath, or sand bath.

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Likewise cooling deserve to be accomplished by partial submerging into a cooling bath, filled with e.g. Cold water, ice, eutectic ice/salt mixtures, dry ice/solvent mixtures, or liquid nitrogen