key term - Burette

Definition

A burette is a precise volumetric glassware used to dispense controlled amounts of liquid, typically during titrations. It features a long, narrow tube with a tap at the bottom, allowing for accurate measurement of liquid volumes to be added dropwise to a solution. This precision is essential in reactions where the exact concentration and volume of reactants can significantly affect the outcome.

5 Must Know Facts For Your Next Test

1. Burettes are typically calibrated to deliver precise measurements, often graduated in milliliters with markings indicating each 0.1 mL or 1 mL increment.
2. The use of a burette allows for the controlled addition of titrant to an analyte solution, which is crucial in achieving the desired endpoint in acid-base titrations.
3. When using a burette, it is important to read the level of the liquid at the bottom of the meniscus to ensure accuracy.
4. Burettes are often used in conjunction with indicators to identify the endpoint of a titration, where the color change signals that the reaction is complete.
5. To prevent contamination, it's important to rinse the burette with the solution to be used before filling it, ensuring that only the desired reactant is introduced into the titration.

Review Questions

• How does the design of a burette facilitate accurate measurements during titrations?
  • The design of a burette includes a narrow tube and a precise tap at the bottom, which allows for careful control over the flow of liquid. This enables users to add small, measured amounts of titrant dropwise to an analyte solution, which is essential for determining the exact point at which the reaction occurs. By reading from calibrated markings on the burette, users can ensure that they accurately dispense the required volume, leading to more reliable results in titrations.
• Discuss how indicators complement the use of burettes in acid-base titrations.
  • Indicators serve as visual cues during acid-base titrations by changing color at specific pH levels. When using a burette to slowly add titrant to a solution containing an indicator, the color change signifies that the endpoint has been reached. This combination allows chemists to determine when enough titrant has been added to fully react with the analyte, making it possible to calculate concentrations accurately based on the volume dispensed from the burette.
• Evaluate the importance of maintaining proper technique while using a burette and how it affects experimental outcomes in titration.
  • Maintaining proper technique while using a burette is critical for ensuring accurate and reproducible results in titration experiments. For example, ensuring that readings are taken at eye level helps eliminate parallax errors when measuring liquid volumes. Additionally, properly rinsing and filling the burette prevents contamination and ensures that only the intended reactants are used. Any inaccuracies introduced by poor technique can lead to erroneous conclusions about concentrations or reaction completeness, highlighting the importance of precision in analytical chemistry.

Related terms

Titration: A technique used to determine the concentration of an unknown solution by adding a solution of known concentration until the reaction reaches completion.

Indicator: A substance that changes color at a specific pH level, used to visually signal the endpoint of a titration.

Meniscus: The curved surface of a liquid in a container, which is important for accurately reading measurements in volumetric glassware.