## Learning Objectives

Upon completion of this exercise, you should be able to:

- Define percentage error and state the percentage error tolerated in most prescription formulas.
- Calculate the potential percentage error for weighing a stated amount of a substance given the sensitivity of the balance.
- Define least weighable quantity.
- Calculate the least weighable quantity for any balance, given the allowed percentage error and the sensitivity of the balance.
- Describe and/or demonstrate the proper techniques for using the Class III prescription balance and corresponding weights to measure solid or liquid substances with an error of measurement not to exceed ± 5%.
- Differentiate between volumetric/nonvolumetric and TD/TC glassware or devices.
- Select glassware/liquid measurement devices which are appropriate for a particular measurement operation.
- Describe and/or demonstrate the proper techniques for using pipets, syringes, and graduates for measuring and delivering liquids.
- Given the specific gravity or density of a compound, or references in which to locate these, perform calculations to convert the weight of the compound to its corresponding volume (or volume to corresponding weight).