Editing Volumetric flask (section)

{{Short description|Laboratory glassware}}
[[File:Brand volumetric flask 100ml.jpg|thumb|A 100 ml volumetric flask with stopper]]
[[Image:Volumetric flasks.jpg|thumb|Volumetric flasks of various sizes.]]

A '''volumetric flask''' ('''measuring flask''' or '''graduated flask''') is a piece of [[laboratory apparatus]], a type of [[laboratory flask]], calibrated to contain a precise volume at a certain temperature. Volumetric flasks are used for precise dilutions and preparation of [[standard solution]]s. These flasks are usually pear-shaped, with a flat bottom, and made of glass or plastic. The flask's mouth is either furnished with a plastic snap/screw cap or fitted with a [[ground glass joint|joint]] to accommodate a [[Polytetrafluoroethylene|PTFE]] or glass stopper. The neck of volumetric flasks is elongated and narrow with an etched ring [[Graduation (instrument)|graduation]] marking. The marking indicates the volume of liquid contained when filled up to that point. The marking is typically [[Calibration|calibrated]] "to contain" (marked "TC" or "IN") at 20&nbsp;°C and indicated correspondingly on a label. The flask's label also indicates the [[Real versus nominal value|nominal]] [[volume]], [[Engineering tolerance|tolerance]], precision class, relevant manufacturing standard and the manufacturer's logo. Volumetric flasks are of various sizes, containing from a fraction of a milliliter to hundreds of liters of liquid.