Question

What are the different types of volumetric glassware and equipment, and the circumstances under which each would be used?

Answer 1

The different types of volumetric glassware are

i) graduated cylinder

ii) volumetric flask.

iii) volumetric burets.

iv) volumetric pipets.

i ) graduated cylinder - graduated cylinders, are used to measure and dispense known volumes of liquids. They are manufactured to contain the measured volume with an error of 0.5 to 1%. For a 100 mL graduated cylinder, this would be an error of 0.5 to 1.0 mL. Measurements made with a graduated cylinder can be reported to three significant figures.

ii) volumetric flasks - volumetric flasks are used to obtain precise volume measurements. A high quality volumetric flask can have an accuracy of plus or minus 0.05%. They are normally used in the preparation of solutions and also for the precise dilution of solutions (i.e. diluting a solution 1:100 would require the transfer of 1 ml of original solution to a 100 ml volumetric flask, and then filling the flask to its 100 ml calibration mark with solvent).

iii) volumetric burets - A buret is a long, narrow tube with a stopcock at its base. It is used for accurately dispensing variable volumes of liquids or solutions. It is graduated in 0.1 mL increments, with the 0.00 mL mark at the top and the 50.00 mL mark near the bottom. burets of 10ml ,25 ml are also available.burets are used to deliver approximate volumes of liquid. Because there is a stopcock at the bottom and a tapered, small diameter tip, liquids can be released in very small, accurately measured amounts. These are especially useful for titration.

iv) volumetric pipets - Pipets are designed to deliver a known volume of a liquid. Their volumes range from less than 1 mL to about 100 mL. volumetric pipets  are meant to hold a single, specific volume. This type of pipet is a narrow tube with a "bubble" in its center, a tapered tip for delivery of liquid, and a single graduation mark near the top (opposite the tapered end) of the tube. Volumetric pipets, sometimes called transfer pipets, are the most accurate pipets. They generally deliver the specified volume ±0.1%, an error of a few hundredths of a milliliter.