Laboratory flask
Laboratory flasks are vessels (containers) which fall into the category of laboratory
A laboratory is a facility that provides controlled conditions in which scientific 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...

 equipment known as 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 laboratories...

. In laboratory and other scientific settings, they are usually referred to simply as flasks. Flasks come in a number of shapes and a wide range of sizes, but a common distinguishing aspect in their shapes is a wider vessel "body" and one (or sometimes more) narrower tubular sections at the top called necks which have an opening at the top. Laboratory flask sizes are specified by the volume they can hold, typically in metric units such as milliliters (mL or ml) or liter
- External links :*...

s (L or l). Laboratory flasks have traditionally been made of glass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...

, but can also be made of plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...


At the opening(s) at top of the neck of some glass flasks such as round-bottom flask
Round-bottom flask
Round-bottom flasks are types of flasks having spherical bottoms used as laboratory glassware, mostly for chemical or biochemical work. They are typically made of glass for chemical inertness; and in modern days, they are usually made of heat-resistant borosilicate glass...

s, retort
In a chemistry laboratory, a retort is a glassware device used for distillation or dry distillation of substances. It consists of a spherical vessel with a long downward-pointing neck. The liquid to be distilled is placed in the vessel and heated...

s, or sometimes volumetric flask
Volumetric flask
A volumetric flask is a piece of laboratory glassware, a type of laboratory flask, used in analytical chemistry for the preparation of solutions. It is made of glass or plastic and consists of a flat bottomed bulb with a long neck, usually fitted with a stopper. The stopper is normally made in a...

s, there are outer (or female) tapered (conical) 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. Some flasks, especially volumetric flasks, come with a stopper or cap for capping the opening at the top of the neck. Such stoppers can be made of glass or plastic. Glass stoppers typically have a matching tapered inner (or male) ground glass joint surface, but often only of stopper quality. Flasks which do not come with such stoppers or caps included may be capped with a rubber bung or cork
Cork (material)
Cork is an impermeable, buoyant material, a prime-subset of bark tissue that is harvested for commercial use primarily from Quercus suber , which is endemic to southwest Europe and northwest Africa...


Flasks can be used for making solutions or for holding, containing, collecting, or sometimes volumetrically measuring chemicals, samples, solution
In chemistry, a solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.- Types of solutions :...

s, etc. for chemical reaction
Chemical reaction
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity...

s or other processes such as mixing, heating, cooling, dissolving, precipitation
Precipitation (chemistry)
Precipitation is the formation of a solid in a solution or inside anothersolid during a chemical reaction or by diffusion in a solid. When the reaction occurs in a liquid, the solid formed is called the precipitate, or when compacted by a centrifuge, a pellet. The liquid remaining above the solid...

, boiling
Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the temperature at which the vapor pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding environmental pressure. While below the boiling point a liquid...

 (as in distillation
Distillation is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....

), or analysis.

List of flasks

There are several types of laboratory flasks, all of which have different functions within the laboratory. Flasks, because of their use, can be divided into:
  • Reaction flasks, which are usually spherical (i.e. round-bottom flask) and are accompanied by their necks, at the ends of which are ground glass joints to quickly and tightly connected to the rest of the apparatus (such as a reflux condenser or dropping funnel). The reaction flask is usually made of thick glass and they can tolerate large pressure differences, with the result that you can keep two both in a reaction under vacuum, and pressure, sometimes simultaneously. Some varieties are:
    • Multiple neck flasks, which can have two to five, or less commonly, six necks, each topped by ground glass connections are used in more complex reactions that require the controlled mixing of multiple reagents.
    • Schlenk flask is a spherical flask with a ground glass opening and a hose outlet with a vacuum stopcock. The tap makes it easy to connect the flask to a vacuum-nitrogen line through the hose and carrying out the reaction either in vacuum or in atmosphere nitrogen
  • Distillation flasks, which are intended to contain mixtures, which are subject to distillation, as well as to receive the products of distillation, distillation flasks are available in various shapes. Similar to the reaction flask, the distillation flasks usually have only one narrow neck and a ground glass joint and are made of thinner glass than the reaction flask, so that it is easier to heat. They are sometimes spherical, test tube shaped, or pear-shaped, also known as a Kjeldahl Flask, due to its use with Kjeldahl bulbs.
  • Reagent flasks are usually a flat-bottomed flask, which can thus be conveniently placed on the table or in a cabinet. These flasks cannot withstand too much pressure or temperature differences, due to the stresses which arise in a flat bottom, these flasks are usually made of weaker glass than reaction flasks. Certain types of flasks are supplied with a ground glass stopper in the, and others that are threaded neck and closes with an appropriate nut or automatic dispenser, these flasks are available in two standard shapes:
    • Round-bottom flasks are shaped like a tube emerging from the top of a sphere. The flasks are often long neck; sometimes they have the incision on the neck, which precisely defines the volume of flask. They can be used in distillations, or in the heating a product. These types of flask are alternatively called Florence flasks.
    • Erlenmeyer flask [introduced in 1861 by German chemist Emil Erlenmeyer (1825–1909)] - is shaped like a cone, usually completed by the ground joint, the conical flasks are very popular because of their low price (they are easy to manufacture) and portability
  • Volumetric flask is used for preparing liquids with volumes of high precision. It is a flask with an approximately pear-shaped body and a long neck with a circumferential fill line.
  • Dewar flask is a flask with a hollow space in the wall to hold a vacuum. These come in a variety of shapes and sizes; some are large and tube-like, others are shaped like regular flasks.
  • Retorts are simplified distillation apparatuses, with long, down turned necks, and round bases. They have largely been replaced by condensers.
  • Büchner flask or Sidearm flask or Suction flask - they are a flat-bottomed flask, but made of very thick and resistant glass. They are usually a cone shape - similar to the shape of an Erlenmeyer flask, but also have side neck, usually affixed to the side, 2 / 3 up from the bottom. The flasks are used to cooperate with vacuum aspirator or vacuum pumps in the vacuum filtration, or as additional security during the distillation and other processes carried out under reduced pressure.
  • Culture flasks for growing cells are designed to improve aeration by including baffles that aid in mixing when placed on a shaker table.

Many of these flasks can be wrapped in a protective outer layer of glass, leaving a gap between the inner and outer walls. These are called jacketed flasks; they are often used in a reaction using a cooling fluid.

Legal issues

Like many other common pieces of glassware, Erlenmeyer flasks could potentially be used in the production of drugs. In an effort to restrict such production, some U.S. states (including Texas) have made possession of common flasks illegal without permit, including Erlenmeyer flasks, as well as chemicals identified as common starting materials.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.