Chemistry Entry Test Success Point

Uncertainty in Measurement 1.         Any measurement is only as good as the “skill of the person” doing the work and the “reliability of the equipment used”. In scientific work, we recognize two kinds of numbers; exact numbers and inexact numbers. 2.         Exact numbers are those that are known with exactly or are integers that result from counting numbers of objects. For example; by definition there are exactly 12 eggs in a dozen, exactly 1000 g in a kilogram and exactly 2.54 cm in an inch. 3.         Inexact numbers are those whose values have same uncertainty. Numbers obtained by measurement are always inexact i.e. uncertainties always exist in measured quantities. This is due to inherent limitations in the equipment used to measure quantities (equipment error) and there are differences in how different peoples make the same measurement (human error...