Burettes

A burette (also buret) is a laboratory equipment used in analytical chemistry for the dispensing of variable, and for measuring amount of a chemical solution. It is a long glass tube with taper end that are attached with a stopcock at the opposite of the terminal valve. The flow of liquid from the tube to the burette tip is controlled by the stopcock valve.  In General Chemistry lab, the burette utilized a 50-mL volume with a stopcock without lubrication. Mainly, there are two types of Burette which are volumetric burette and Piston burette or Digital burette. A volumetric burette delivers measured volumes of liquid. Piston burettes are similar to syringes, but with a precision bore and a plunger. Piston burettes may be manually operated or may be motorized. A weight burette delivers measured weights of liquid.

A burette is a volumetric measuring glassware which is used in analytical chemistry for accurate dispensing of variable, and for measuring the volume of a liquid, especially of one of the reagents in a titration. In a titration of an acid and base solution, the burette can be filled with acid. By turning the tap in a perpendicular direction, the tap can be opened, which then allows the acid in the tube to be able to be added drop by drop into a the flask.The experiment is taken out by gradually filling a liquid samples. Titrant or titrated solution is a good example. Burette support the process by its long narrow tubed with a stopcock at the taper end. The addition will halt when there the correspondence point is set up.

Burettes can perform titrations precisely for delivering a  volumetric measurement of a fluid. The burette tube consists of the graduation marks which provides the total volume of the acid at that point. Compared to pipette, greater precision can be attained by using burette.

The burette is used to measure a volume of a substance in a specific amount, but different from measuring cylinder as its graduations measure from top to bottom. Therefore the difference between the starting and the final volume is equal to the amount dispensed. The precise measurement of the burette is beneficial for using in titration in order to add titrant to the titrated solution.

Volumetric burette can be glass or plastic stright tube with a graduation scale. At the tip of burette, there are a stopcock and valve to control the flow of the chemical solution. The barrel of the stopcock can be made of glass or the plastic PTFE. Stopcocks with glass barrels need to be lubricated with vaseline or a specialized grease. Burettes are manufactured for specific tolerances, designated as class A or B and this also is etched on the glass.

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