Round-bottom flask

Round Bottom Flask

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Round-bottom flask

Round-bottom flasks (also called round-bottomed flasks and Erlenmeyer Bulbs) are types of flask

FLASK

The Flux Advanced Security Kernel is an operating system security architecture that provides flexible support for security policies.FLASK is a core framework in Security_focused_operating_system operating systems such as National_Security_Agency's Security-Enhanced Linux , OpenSolaris FMAC and FreeBSD#TrustedBSD....
s having spherical bottoms used as laboratory glassware

Laboratory glassware

Laboratory glassware refers to a variety of equipment, traditionally made of glass, used for scientific experiments and other work in science, especially in chemistry and biology laboratory....
, mostly for chemical

Chemistry

Chemistry is the science concerned with the composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions....
or biochemical

Biochemistry

Biochemistry is the study of the chemistry processes in living organisms. It deals with the structure and function of cellular components such as proteins, carbohydrates, lipids, nucleic acids and other biomolecules....
work.

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Encyclopedia

Round-bottom flasks (also called round-bottomed flasks and Erlenmeyer Bulbs) are types of flask

FLASK

Laboratory glassware

Chemistry

Chemistry is the science concerned with the composition, structure, and properties of matter, as well as the changes it undergoes during chemical reactions....
or biochemical

Biochemistry

Glass

Glass generally refers to a Hardness, brittle, transparency amorphous solid, such as that used for windows, many Glass Bottles, or eyewear, including, but not limited to, soda-lime glass, borosilicate glass, acrylic glass, sugar glass, Muscovite , or aluminium oxynitride....
for chemical inertness; and in modern days, they are usually made of heat-resistant borosilicate glass. There is at least one tubular section known as the neck with an opening at the tip. Two or three-necked flasks are common as well. Round bottom flasks come in many sizes, from 5 mL to 5 L, with the sizes usually inscribed on the glass. In pilot plants even larger flasks are encountered.

The ends of the necks are usually conical (female) ground glass joint

Ground glass joint

Ground glass joints are used in laboratories to quickly and easily fit leak-tight apparatus together from commonly available parts. For example, a round bottom flask, Liebig condenser, and oil bubbler with ground glass joints may be rapidly fitted together to reflux a reaction mixture....
s. These are standardized, and can accept any similarly-sized tapered (male) fittings. Standard Taper 24/40 is common for 250 mL or larger flasks, while smaller sizes such as 14 or 19 are used for smaller flasks.

Because of the round bottom, cork rings are needed to keep the round bottom flasks upright. When in use, round-bottom flasks are commonly held at the neck by clamps on a stand.

Applications

The round bottoms on these types of flasks allow more uniform heating and/or boiling of liquid. Thus, round-bottom flasks are used in a variety of applications where the contents are heated or boiled. Round-bottom flasks are usually used in distillation

Distillation

Distillation is a method of separation process mixtures based on differences in their Volatility in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....
by chemists as distilling flasks and receiving flasks for the distillate (see distillation diagram). One-neck round-bottom flasks are used as the distilling flasks in rotary evaporator

Rotary evaporator

A rotary evaporator is a device used in chemical laboratories for the efficient and gentle removal of solvents from samples by evaporation. When referenced in the chemistry research literature, description of the use of this technique and equipment may include the phrase "rotary evaporator", though use is often rather signaled by other lang...
s.

Round-bottom flasks are often used to contain chemical reaction

Chemical reaction

A chemical reaction is a process that always results in the interconversion of chemical substances. The substance or substances initially involved in a chemical reaction are called reactants....
s run by chemists, especially for reflux

Reflux

Reflux is a technique involving the condensation of vapors and the return of this condensate to the system from which it originated. It is used in industrial and laboratory distillations....
set-ups and laboratory

Laboratory

A laboratory is a facility that provides controlled conditions in which science research, experiments, and measurement may be performed. The title of laboratory is also used for certain other facilities where the processes or equipment used are similar to those in scientific laboratories....
-scale synthesis

Synthesis

The term synthesis is used in many fields, usually to mean a process which combines together two or more pre-existing elements resulting in the formation of something new....
. Boiling chip

Boiling chip

Boiling chips, also known as boiling stones, boileezers or anti-bumping granules, are small, irregularly shaped stones added to liquids to make them boiling more smoothly mainly in distillation....
s are often added in distilling flasks for distillations or boiling chemical reactions to allow a nucleation site for gradual boiling. This nucleation avoids a sudden boiling surge where the contents may overflow from the boiling flask. Stirring bar

Stir bar

A stir bar is a magnetic bar used to stir a mixture or solution in a laboratory. The stir bar rotates in synch with a separate rotating magnet located beneath the vessel containing the reaction....
s or other stirring devices suited for round-bottom flasks are sometimes used. For a reflux set-up, a condenser

Condenser (laboratory)

In a laboratory a condenser is a piece of laboratory glassware used to cool hot vapors or liquids. A condenser usually consists of a large glass tube containing a smaller glass tube running its entire length, within which the hot fluids pass....
is typically attached to the middle or only neck of the flask being used. Additional necks on a flask could allow a thermometer

Thermometer

The thermometer is a device that measures temperature or temperature gradient using a variety of different principles; it comes from the Greek language roots thermo, heat, and meter, to measure....
or a mechanical stirrer to be inserted into the flask contents. The additional necks can also allow a dropping funnel

Dropping funnel

A dropping funnel is a type of laboratory glassware used to transfer fluids. They are fitted with a stopcock which allows the flow of to be controlled....
to be attached to let reactants slowly drip in.

Special electrically powered heating mantles are available in various sizes into which the bottoms of round-bottom flasks can fit so that the contents of a flask can be heated for distillation, chemical reactions, boiling, etc. Heating can also be accomplished by submerging the bottom of the flask into a heat bath

Heat bath

A heat bath is a system whose heat capacity is so large that when it is in thermal contact with some other system of interest its temperature remains constant....
, water bath

Water bath

A water bath can refer to:* A Bain-marie* A heated bath...
, or sand bath

Sand bath

A sand bath is a common piece of laboratory equipment made from a container filled with heated sand. It is used to provide even heating for another container, most often during a chemical reaction....
. Similarly cooling can be accomplished by partial submerging into a cooling bath

Cooling bath

A cooling bath is a mixture used in a laboratory when low temperatures are needed, for example to conduct low-temperature chemical reactions , to collect highly volatile liquids from distillation, or in cold traps....
, filled with e.g. cold water

Water

Water is a common chemical substance that is essential for the survival of all known forms of life. In typical usage, water refers only to its liquid form or States of matter, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam....
, ice

Ice

Ice is a solid phases of matter, usually crystalline solid, of a non-metallic substance that is liquid or gas at room temperature, such as ammonia ice or methane ice....
, eutectic ice/salt mixtures, dry ice

Dry ice

Dry ice is solid carbon dioxide. It is commonly used as a versatile cooling agent.Dry ice Sublimation , changing directly to a gas at atmospheric pressure....
/solvent mixtures, or liquid nitrogen

Liquid nitrogen

Liquid nitrogen is a liquefied atmospheric gas produced industrially in large quantities by fractional distillation of liquid air. It is pure nitrogen in a liquid state at very low temperature....

Related glassware

Flat-bottomed flask A flask with similar uses as the round-bottom flask, but the flat bottom allows it to stand on a level surface.
Florence flask
Florence flask

A Florence flask is a type of flask used as an item of laboratory glassware. It can be used as a container to hold solutions of chemicals. A Florence flask has a round body with a single long neck and with either a round or a flat bottom....
s are similar flasks that have round bodies and either a round bottom or a flat bottom so that one can stand the flask on a level surface. Florence flasks typically have one neck which is longer and may be somewhat wider than the usual neck of a round bottom flask. The necks of traditional Florence flasks often don't have a ground glass joint like modern round bottom flasks do. Round-bottom flasks are used more commonly by professional chemist
Chemist

A chemist is a scientist trained in the science of chemistry. Chemists study the composition of matter and its properties such as density, acidity, size and shape....
s than Florence flasks.
Retort
Retort

In a chemistry laboratory, a retort is a glassware device used for distillation or dry distillation of substances. It consists of a sphere vessel with a long downward-pointing neck....
a spherical vessel with a long downward-pointing neck, specially used for distillation or dry distillation
Dry distillation

Dry distillation is the heating of solid materials to produce liquid or gaseous products . The method may or may not involve pyrolysis/thermolysis....
of substances.
Schlenk flask
Schlenk flask

A Schlenk flask, or Schlenk tube is a reaction vessel typically used in air sensitive chemistry, invented by Wilhelm Schlenk. It has a side arm fitted with a Polytetrafluoroethylene or ground glass stopcock which allows the vessel to be evacuated or filled with gases ....
- a round-bottom flask with a built-in plug valve or stopcock
Stopcock

A stopcock is a valve used to restrict or isolate the flow of a liquid or gas through a pipe .In Great Britain a stopcock, not to be confused with a gate valve or a DiCiaccio branch, is used to prevent flow of water into a domestic water system....
.