Volumetric flask

Volumetric flask

A typical volumetric flask
Other names	Measuring flask
Uses	Preparation of standard solutions
Related items	Beaker, Erlenmeyer flask, Graduated cylinder

A volumetric flask is a type of laboratory glassware used in analytical chemistry for the precise preparation of standard solutions and accurate dilutions. It is characterized by its flat bottom, long neck, and a single graduation mark etched on the neck, which indicates a specific volume.

Design and Features

Volumetric flasks are typically made from borosilicate glass or polyethylene and come in various sizes, ranging from 1 mL to 10,000 mL. The neck of the flask is narrow, which allows for precise measurement of liquids. The single graduation mark ensures that the volume of liquid can be measured with high accuracy, usually within ±0.05%.

Uses

Volumetric flasks are primarily used in the preparation of standard solutions, which are solutions of known concentration. They are also used for precise dilutions, where a solution of known concentration is diluted to a lower concentration. This is essential in various quantitative analyses in chemistry and biochemistry.

Procedure

To use a volumetric flask, a specific amount of solute is first added to the flask. The solvent is then added until the liquid level reaches the graduation mark on the neck of the flask. The flask is then capped and inverted several times to ensure thorough mixing of the solute and solvent.

Calibration

Volumetric flasks must be calibrated to ensure accuracy. Calibration involves filling the flask with a liquid of known density and measuring the volume. This process is crucial for achieving precise measurements in analytical chemistry.

Related Equipment

• Beaker: A simple container used for stirring, mixing, and heating liquids.
• Erlenmeyer flask: A conical flask used for mixing by swirling without risk of spillage.
• Graduated cylinder: A cylindrical container used for measuring the volume of liquids.

See Also

• Analytical balance
• Pipette
• Burette
• Titration