Volumetric Flask Definition in Chemistry

A volumetric flask is a type of laboratory glassware used to prepare solutions. A volumetric flask is a flat bottomed bulb with a elongated neck calibrated to hold a set volume at a mark on the neck. The flask may also be called a graduated flask or measuring flask because its mark specifies a precise volume measurement. The mark on the flask neck indicates the volume contained. When emptied, some portion of liquid may remain in the container, so the mark (unlike for a pipette) does not indicate the amount to be dispensed. It should be noted volumetric flasks are calibrated for a particular temperature (usually 20 °C), which is indicated on the label.

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Ultimate Guide to Volumetric Flasks

By Anne Marie Helmenstine, Ph.D.

Most volumetric flasks are either transparent glass or plastic, although some flasks are amber-colored for the preparation of light-sensitive solutions. The mouth of the flask may have either a joint to accommodate a stopper or a screw cap.

Volumetric Flask Standards

All volumetric flasks are not created equal! There are higher and lower precision flasks. A volumetric flask made to conform to a high standard is a Class A or Class 1 flask. Its tolerance, temperature, precision, and volume will be indicated on the glassware. A Class B flask does not conform to as high a standard and may not include all of this information. Class A flasks are used for analytical chemistry work, while Class B flasks are suitable for most educational and qualitative work.