Thursday, July 12, 2012

Laboratory Glassware: Burettes

This Glassware is widely known, also called Burets, it has a particular shape.

Laboratory_Glassware_Burette
Source: www.progress.com.sg

Characteristics
The burette has a long cylindrical shape, filled with volumetrical graduations along the cylinder, it has a stopcock with a plug and a bore, made generally out of glass, borosilicate or pyrex. Pyrex burettes are rarely seen, pyrex was build to resist heat but this glassware is used for volumetrical purposes and precision is needed, this cannot be achieved if the fluid is hot, because it will eventually cool down, changing the graduation of the glassware and its density aswell, that’s why most of these graduated glassware come with specification about the temperature on which they have been calibrated.

The most common volume found is 25 and 50 ml. But there are 100 ml burettes aswell.

100ml_burette
Source: www.geckooptical.com

Uses
Used mainly in titrations, to dose an exact volume of a reactant on a certain reaction. Some use it to measure liquid volumes but its not recommended as there are other glassware on a science lab for those purposes.
Burette_Arrangement
Source: www.indigo.com

The first time I learned how to use this glassware was on laboratory science courses, when I was just starting at the university, it has a particular procedure to use it properly.

More Laboratory Glassware

Saturday, July 7, 2012

Laboratory Glassware: Boiling Flasks

This Laboratory Glassware is also known as Florence Flask, some variations called them Round-bottom flasks.

Lab_Glassware_Boiling_Flask
Source: www.labdepotinc.com
Characteristics
It’s used to contain or hold liquids and fluids; the shape is very characteristic, it has a round bottom and a long neck, and some have conical ground glass joints in the top commonly used to other standardized fittings.Made of glass or heat-resistant borosilicate glass.
The round bottom makes it hard to keep them upright, reason why it is commonly held at the neck by clamps on a stand.

Two or Three-necked boiling flasks are common in most laboratories.

two_necked_Boiling_Flaskthree_necked_Boiling_Flask

Uses
As its names describes, its used for boiling liquids, the shape allows a more uniform heating or boiling, they are most used on distillations on rotatory evaporators, they are also used on reflux processes of laboratory-scale synthesis.

Boiling_Flask
Source:www.lotusoverseas.com 
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