Burette

Definition

A burette is a precision laboratory glassware used to dispense variable amounts of a liquid, typically during titrations. Its design features a long, graduated tube with a stopcock at the bottom, allowing for controlled release of liquids in small, accurate increments. This makes it essential for determining the concentration of an unknown solution by gradually adding a titrant until a reaction endpoint is reached.

5 Must Know Facts For Your Next Test

1. Burettes are usually made of glass and are calibrated to deliver accurate volumes of liquid, typically ranging from 25 mL to 100 mL.
2. The stopcock allows for precise control over the flow of liquid, enabling dropwise addition which is crucial for detecting the endpoint in titrations.
3. When filling a burette, it is important to eliminate air bubbles from the tip to ensure accurate measurements.
4. Proper technique involves reading the measurement at eye level to avoid parallax error when determining the volume in the burette.
5. Burettes can be filled using a funnel or directly from a reagent bottle, but care must be taken to avoid contamination.

Review Questions

• How does the design of a burette contribute to its effectiveness in performing titrations?
  • The burette's long graduated tube allows for precise measurement and delivery of liquid, essential for achieving accurate titration results. The stopcock enables controlled release of the titrant, which is critical for identifying the endpoint of the reaction. This combination of design features allows chemists to add reagents incrementally and carefully monitor changes, ensuring precision in their experiments.
• Discuss how the use of a burette can affect the accuracy and reliability of titration results.
  • Using a burette enhances both accuracy and reliability during titrations due to its precise volume calibration and ability to deliver liquid dropwise. Accurate readings depend on proper technique, such as aligning the meniscus at eye level and ensuring no air bubbles are present. These factors minimize human error and contribute to consistent results across multiple trials, making the burette an indispensable tool in quantitative analysis.
• Evaluate the implications of improper handling or reading of a burette on experimental outcomes in titrations.
  • Improper handling or reading of a burette can lead to significant errors in titration results, potentially affecting conclusions drawn from experiments. For example, failing to read at eye level can cause parallax error, leading to incorrect volume measurements. Additionally, if air bubbles remain in the tip or if cross-contamination occurs during filling, this can skew results, making it difficult to accurately determine concentration and affecting overall data integrity. Understanding and mitigating these risks are crucial for achieving reliable outcomes in quantitative analyses.

Related terms

Titration: A quantitative analytical method used to determine the concentration of a solute in a solution by reacting it with a reagent of known concentration.

Endpoint: The point in a titration at which the reaction is complete, often indicated by a color change or other observable effect.

Meniscus: The curve seen at the surface of a liquid in response to its container; when reading measurements in a burette, the bottom of the meniscus should be aligned with the graduation mark.