what is a flask used for in chemistry

what is a flask used for in chemistry

Infographic showing graphic representations of various items of laboratory glassware and listing their names.

Glassware within the laboratory is available in a spread of various sizes and styles, and is used for quite a lot of functions. Don’t know your round-bottomed flask out of your Florence flask, or your pipettes out of your burettes? This graphic has you lined. Under there’s additionally a bit element on the utilization of every.

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Fundamental Glassware

Basic Apparatus

This stuff needs to be acquainted to anybody who’s been in a chemistry sensible lesson at school. Check tubes are the archetypal picture of chemistry, while beakers additionally make frequent appearances at school practicals. Boiling tubes aren’t that completely different from check tubes in look, however are used when heating is required – they are typically manufactured from thicker glass, and are barely bigger and wider.



Of all of the flasks utilized in chemistry, probably the most iconic is the conical (Erlenmeyer) flask. Named after the German chemist Emil Erlenmeyer, who created the flask in 1860, it’s designed in order that its contents will be swirled simply with out spilling out. This additionally makes them helpful for boiling liquids, and moreover their necks can help filter funnels.

Volumetric flasks are used primarily within the preparation of ordinary options. To create an answer of a selected focus, we have to know the amount of the answer; the slim neck of the volumetric flask could have a skinny commencement to indicate the place a selected quantity is reached.

Spherical-bottomed flasks and Florence flasks look very comparable, however there’s a slight distinction between the 2. Each have spherical bottoms, designed to unfold out warmth evenly when they’re heated. They’re regularly utilized by chemists for reactions and in rotary evaporators. Whereas round-bottomed flasks will often have a floor glass joint on their neck, to permit connection to different equipment, Florence flasks, supposedly named after Florence in Italy, are likely to merely have a lip. They will additionally include both a flat backside so they’re free-standing, or a rounded backside, and have longer necks.

The Kjeldahl flask has a fair longer neck, and was developed to be used within the Kjeldahl technique, which is used to find out the nitrogen content material in a substance.

Pear-shaped flasks are often fairly small flasks, used for small-scale distillations. Their form permits restoration of extra materials than the round-bottomed flasks.

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The fairly odd-looking retort flasks are utilized in distillations, although their use was primarily earlier than the arrival of condensers. Right now, they’re very not often used.

The Schlenk flask and the Straus flask are one other two that look pretty comparable. Schlenk flasks are generally utilized in air-sensitive chemistry, because the facet arm permits an inert fuel reminiscent of nitrogen to be pumped into the vessel. The Straus flask, however, is used to retailer dried solvents. The primary neck is definitely crammed in midway up, and related to a plugged smaller neck; this primary neck will be related to different equipment, and permits the solvent to be extracted when the plug is barely withdrawn or eliminated solely.

Lastly, the Claisen flask, designed by chemist Ludwig Claisen, is designed for vacuum distillation; distillation beneath vacuum produces problematic quantities of bubbles when options are boiled. Claisen’s flask features a capillary tube that inserts small bubbles into the liquid, easing the ferocity of boiling, while the branched portion of the flask hosts a thermometer. Right now, Claisen’s flask is much less generally used.

Funnels, Evaluation & Separation


Quite a lot of completely different equipment can be utilized for filtration. The obvious is the filter funnel, into which filter paper will be positioned, and a mix can then be poured by. The smaller thistle funnel is just not used for filtering in any respect, however so as to add liquids into equipment.

The Buchner flask can be utilized at the side of a Buchner funnel in vacuum filtration, and is a a lot faster course of than the gravity filtration used with regular filter funnels. A vacuum tube will be affixed to the flask’s sidearm, which quickly sucks by the solvent, leaving any strong within the Buchner funnel.

For separating options or liquids of various densities, separating funnels can be utilized. Liquids of a decrease density will float to the highest, then the mixtures will be tapped off individually. The same-looking dropping funnel is used so as to add liquids or options to a response.

One other technique of separating mixtures of compounds is column chromatography, which will be carried out utilizing a chromatography column. The combination is handed by a column of silicon dioxide or aluminium oxide, with completely different elements of the combination taking differing quantities of time to cross by the column.

Lastly, the Thiele tube is a bit of equipment used to find out the melting level of a strong compound. It comprises and heats an oil bathtub, into which a pattern will be positioned together with a thermometer. Heating then permits melting level to be decided. The design of the flask permits the oil to flow into, making certain even heating.



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A spread of various condensers will be utilised in laboratories as necessary elements of distillation equipment. Probably the most generally seen condenser in colleges is the Liebig condenser, which has an internal tube by which vapour flows, surrounded by a ‘jacket’ by which cool water passes and condenses the vapour. The Graham condenser is just like this, however has a coiled path for the vapour to circulation by and condense. In the meantime, the Friedrichs condenser inverts the association, having a spiral coil by which the coolant flows, with the vapour surrounding it. Different types of condenser are additionally obtainable, although aren’t proven right here.

One other piece of glassware that falls loosely into this class is the fractionating column. This helps separate a mix throughout distillation, as vapours gather and distill on the small glass ‘trays’ ascending the column. Solely probably the most risky gases will ascend all the way in which to the highest of the column to be distilled off.

Measuring Equipment


Quite a few items of chemistry glassware are used to precisely measure volumes; the obvious being the graduated cylinder, or measuring cylinder, which might are available a wide range of sizes.

For measuring volumes of options extra exactly, a volumetric pipette can be utilized. These are available a wide range of sizes, every measuring a set quantity of resolution. Graduated pipettes can be used, which permit numerous small volumes to be measured out. For measurement of volumes throughout titrations (the addition of 1 resolution to a different to find out an unknown focus) burettes are used. These are lengthy, slim tubes, with incremental quantity markings, which permit exact volumes of options to be dropped into one other resolution.

For measuring the amount of fuel produced in a response, a fuel syringe can be utilized. This piece of equipment will be connected to the highest of a flask by way of a bit of tubing, and the fuel produced pushes the plunger out of the syringe, permitting the fuel quantity to be measured.

The one piece of glassware we haven’t talked about is the Soxhlet extractor. That is used to extract chemical substances from a strong pattern right into a liquid. You possibly can see it in motion on this video which particulars the extraction of caffeine from espresso.

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References & Additional Studying

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  • Traditional equipment – Chemistry World