Erlenmeyer flask

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For the episode of The X-Files, see The Erlenmeyer Flask.

An Erlenmeyer flask (also known as a conical flask) is a widely used type of laboratory flask which features a conical base with a cylindrical neck. They are usually marked on the side (graduated) to indicate the approximate volume of their contents. It is named after the German chemist Richard Erlenmeyer, who created it in 1861.

The conical flask's counterpart is the beaker. However the main difference is its narrow neck. The neck allows the flask to be stoppered using rubber bungs or cotton wool. The conical shape allows the contents to be swirled or stirred during an experiment (as is required in titration); the narrow neck keeps the contents from spilling. The smaller neck also slows evaporative loss better than a beaker. The flat bottom of the conical flask makes it unlikely to tip over, unlike the Florence flask.

Image:Titration.gif

The flask is used to heat or boil substances over a Bunsen burner flame or hot plate. If prolonged heating (such as in a heating bath) is required, a Florence flask may be better. Erlenmeyer flasks are also used for titration and in microbiology for the preparation of microbial cultures.

If the flask is to be heated in an oil or water bath, a 'C' shaped lead or iron weight may be placed over the outside to keep the flask firmly planted.

When heating, it is usually placed on a ring held to a ring stand by means of a ring clamp. The ring keeps it over a Bunsen burner so that it's heated by the burner's flame. When set up this way, a wire gauze mesh or pad is placed between the ring and the flask to prevent the burner's flames from directly touching the glass. An alternative way to set up the apparatus is to clamp the flask directly to the ring stand by means of holding it with a test tube clamp around the flask's neck.

[edit] Legal Issues

Like many other common pieces of laboratory glassware, Erlenmeyer flasks could potentially be used in the production of illegal narcotics. In an effort to restrict such production, some U.S. states (including Texas) have begun requiring permits to purchase such glassware, including Erlenmeyer flasks, as well as chemicals identified as common starting materials.