When using a buret, what is a key operation that should be performed?

Filling the buret before use is essential for several reasons. It ensures that the buret is ready to deliver accurate and precise volumes of liquid during titration or other analytical procedures involving liquid measurements. Proper filling also helps to minimize the risk of air bubbles that can interfere with the measurement. Additionally, it allows the operator to check the starting volume accurately, ensuring that the amount of reagent used can be calculated precisely during experiments.

When preparing to use a buret, it is crucial to consider that the calibration of the buret must be intact, and any air bubbles should be eliminated to enhance the accuracy of the measurements. However, filling the buret properly is the foundational first step that facilitates all these subsequent operations.