Pre-university and university general Chemistry textbooks’ definition and calculation of equilibrium constants

Abstract

In this paper, after presenting the experimental equilibrium constants, Kp and Kc, and the thermodynamic equilibrium constant, Kº, it is analysed the misrepresentation of them by general chemistry textbooks. We examine the way both first-year university chemistry textbooks and preuniversity chemistry textbooks handle the units of equilibrium constants. Many textbooks do not report the corresponding units in the calculation of Kp and Kc. Moreover, in most of the cases, Kº is not defined and as a result confusion about these concepts is widespread. This problem in the terminology used by textbooks causes that many of them confuse Kp with Kº. It is suggested that preuniversity textbooks should correctly define both Kp and Kc, leaving the definition of the thermodynamic constant, Kº, as well as its relationship to Kp and Kc, to first-year university textbooks.