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.
1. something that holds parts together or in place, as a clasp or clamp. 2. anything that imparts rigidity or steadiness. 3. a device for holding and turning a bit for boring or drilling; bitstock. 4. a piece of timber, metal, etc., for supporting or positioning another part of a framework.