Measuring instantaneous rates is the most direct way of determining the rate law of a reaction, but it is not always convenient, and it may not be possible to do so with precision.
piece (pÄs) n. 1. A thing considered as a unit or an element of a larger thing, quantity, or class; a portion: a piece of string. 2. A portion or part that has been separated from a whole: a piece of pie. 3. An object that is one member of a group or class: a piece of furniture.
By Richard Nordquist. Definition: In composition, a particular item of information (including descriptive, illustrative, and statistical information) that supports an idea or contributes to an overall impression in an essay, report, or other kind of text or presentation.