Volumetric flask

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A volumetric flask, also known as a measuring flask or graduated flask, is a type of laboratory glassware used for measuring and preparing solutions with high accuracy. It is designed to hold a specific volume of liquid at a particular temperature, usually at 20 degrees Celsius.

Construction

File:Volumetric flask diagram.png

A diagram of a volumetric flask

A volumetric flask typically consists of a flat-bottomed, pear-shaped glass container with a long neck and a single graduation mark etched on the neck. The neck is fitted with a stopper or a cap to prevent evaporation or contamination of the solution. The flask is made from high-quality borosilicate glass, which is resistant to thermal shock and chemical corrosion.

Usage

Volumetric flasks are used in various scientific disciplines, including chemistry, biology, and pharmaceutical research. They are particularly useful when precise measurements of liquid volumes are required. The accuracy of a volumetric flask is typically within a few hundredths of a milliliter.

To use a volumetric flask, the user first rinses the flask with a small amount of the solution to be prepared. This ensures that the flask is clean and free from any contaminants. The desired amount of solute is then carefully weighed or measured and added to the flask. The solvent, usually water, is added to the flask until the solution reaches the graduation mark on the neck. The flask is then stoppered or capped and inverted several times to ensure thorough mixing of the solute and solvent.

Calibration

Volumetric flasks are calibrated to contain a specific volume of liquid at a particular temperature, usually 20 degrees Celsius. The calibration is done by the manufacturer using specialized equipment and techniques. The accuracy of the calibration is indicated by the tolerance value, which specifies the maximum permissible error in the volume measurement.

Maintenance and Care

To maintain the accuracy and longevity of a volumetric flask, it is important to handle it with care. After each use, the flask should be thoroughly cleaned with a suitable cleaning agent and rinsed with distilled water. It is recommended to store the flask in a clean and dry environment to prevent contamination or damage.

See also

• Laboratory glassware
• Beaker (glassware)
• Erlenmeyer flask