What's the appropriate instrument to measure the volume of a liquid?

The appropriate instrument to measure the volume of a liquid is a graduated cylinder or a burette.

A graduated cylinder and a burette are both pieces of laboratory equipment used to measure the volume of a liquid accurately. They are typically made of transparent glass or plastic and have markings along the side to indicate volume. The choice between a graduated cylinder and a burette depends on the level of precision required in the measurement.

A graduated cylinder is a simple tube, closed at one end, with volume markings from bottom to top. It is used for relatively rough measurements of liquid volumes. To measure a volume, the liquid is simply poured into the cylinder and the level read off against the scale. The accuracy of a graduated cylinder can vary, but it is generally within 1% of the actual volume.

On the other hand, a burette is a more precise instrument. It is a long, narrow tube with a stopcock at the bottom and volume markings along its length. The burette is filled with the liquid to be measured, and the stopcock is opened to allow the liquid to flow out. The volume of liquid dispensed can be read off the scale with a high degree of accuracy, typically within 0.1% of the actual volume.

In addition to these, there are other instruments like pipettes and volumetric flasks which are also used for measuring liquid volumes, especially in analytical chemistry where high precision and accuracy are required. A pipette is a narrow tube with a bulb in the middle, used to draw up and dispense precise volumes of liquid. A volumetric flask, on the other hand, is a flask with a narrow neck and a flat bottom, marked with a line to indicate a specific volume. It is used to prepare solutions of known concentration.

In conclusion, the choice of instrument depends on the precision required in the measurement. For rough measurements, a graduated cylinder is sufficient, while for more precise measurements, a burette, pipette or volumetric flask may be used.