Volumetric flask
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A volumetric flask (sometimes called measuring flask or graduated flask) is a type of laboratory flask, calibrated to contain a precise volume of liquid at a particular temperature, most often water and aqueous solutions.
Contents
General
Volumetric flasks are pear-shaped flasks, with a flat bottom, and made of glass or (rarer) plastic. The flask's mouth is a simple female ground glass joint with a plastic (PE or PTFE) or glass stopper. The neck of the volumetric flasks is elongated and narrow with an etched ring graduation marking. The marking indicates the volume of liquid contained when filled up to that point. The marking is typically calibrated "to contain" (marked "TC" or "IN") at 20 °C and indicated correspondingly on a label. The flask's label also indicates the nominal volume, tolerance, precision class, relevant manufacturing standard and the manufacturer’s logo. The volumetric flasks are of various sizes, containing from 1 to 20 000 mL of liquid. Volumetric flasks are generally colorless, though amber-coloured varieties also exist, being used for the handling of light-sensitive compounds.
Availability
Volumetric flasks can be purchased from lab suppliers. They come in various classes, with A class having the best performances, while B class volumetric flasks being of lower quality and thus are more often used to prepare less precise solutions.
Uses
Volumetric flasks are used for precise dilutions and preparation of standard solutions.
