What does “TC” signify on volumetric glassware?

The designation "TC" on volumetric glassware stands for "to contain." This marking indicates that the volumetric flask or other glassware has been calibrated to hold a specified volume of liquid. When filled to the mark on the flask, it is meant to contain that volume at a specific temperature.

This is essential in laboratory work because it ensures accuracy in measuring out specific quantities of solvents or reagents. For instance, when preparing solutions or diluting substances, using glassware labeled as "TC" helps ensure that the volume reported corresponds accurately to the amount of liquid the glassware can hold, taking into account the properties of the liquid and the determination of volume at given conditions.

In contrast, the other options do not accurately reflect the purpose of the "TC" designation. "To conduct," "to concentrate," and "to calculate" are not standard terms associated with the calibration marks found on volumetric glassware.