Pipettes and Burettes

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Chemistry Laboratory
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Pipettes and burettes are essential instruments in the laboratory, used for measuring and transferring liquids with high precision. Although similar in function, they have specific designs and applications. This section addresses their characteristics, uses, and handling recommendations.

1. Pipettes

  • Description and Types:
    • Volumetric Pipettes: Calibrated to contain an exact volume of liquid. They are single-volume and have a mark that indicates the exact volume.
    • Graduated Pipettes: Have graduations along the tube, allowing for the measurement of different volumes of liquids.
  • Use and Applications:
    • Ideal for measuring precise volumes of reagents in titrations, solution preparation, and chemical experiments.
    • Used with a suction bulb or pipettor to aspirate and dispense liquids.

2. Burettes

  • Description:
    • A long graduated tube with a stopcock at the bottom. Allows for controlled dispensing of liquid.
  • Use and Applications:
    • Mainly used in titrations to measure the volume of solution that has been added to a reaction mixture.
    • Allows for precise and controlled adjustment of liquid flow.

3. Handling and Care

  • Cleaning:
    • Pipettes and burettes should be carefully cleaned after each use to prevent cross-contamination.
    • It is advisable to use specific cleaning solutions and soft brushes to avoid damaging the glass.
  • Calibration:
    • They should be calibrated periodically to ensure accuracy, especially in sensitive quantitative applications.
  • Storage:
    • Store in an upright position and in safe places to prevent falls or damage.

4. Safety Precautions

  • Careful Handling:
    • Avoid bumps or falls, as they are delicate glass instruments and can break easily.
  • Control in Dispensing:
    • When using burettes, ensure proper control of the liquid flow to avoid spills and incorrect measurements.

5. Tips for Effective Use

  • Avoid Air Bubbles:
    • Ensure that there are no air bubbles in the pipettes or burettes, as they can affect the accuracy of the measurements.
  • Correct Reading of the Meniscus:
    • When measuring liquids, observe the meniscus at eye level and take the reading at the lowest part of it.

Pipettes and burettes are crucial tools in the laboratory for the precise measurement of liquids. Their correct use and maintenance are fundamental to obtaining reliable and reproducible experimental results.