Volumetric Flask Definition in Chemistry

What You Need to Know About Volumetric Flasks

Volumetric flasks are used to accurately prepare solutions for chemistry.
Volumetric flasks are used to accurately prepare solutions for chemistry. TRBfoto/Getty Images

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.

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.