Science and Education Publishing
World Journal of Chemical Education
2375-1657
3
6
2015
12
1
Teaching Chemical Equilibria Using Open Source Software OCTAVE
127
133
EN
Juan José
Baeza-Baeza
Departament de Química Analítica, Universitat de València, c/Dr. Moliner, Burjassot, Spain
Francisco Fernando
Pérez-Pla
María Celia
García-Álvarez-Coque
WJCE2015361
10.12691/wjce-3-6-1
2015
7
14
2015
11
6
2015
11
29
The use of computational software can greatly facilitate the teaching of chemical equilibria. It allows the treatment of complex problems without the need of simplifications, and the outcome of a very large number of calculations in a short time. Two practical examples of different complexity are proposed in this work to show the application of a general systematic approach for the numerical calculation of multi-equilibria problems, regardless of the number or types of equilibria involved. The method consists in writing down a system of non-linear equations formed by equilibrium constant expressions and the needed number of conservation balances so to match the number of chemical species involved. The exact solution of the system of non-linear equations describing the multiple equilibria is obtained by means of the fsolve tool of the open source software OCTAVE. The approach also allows multiple calculations by automatic changing of the initial conditions. The graphical representation of the concentration of chemical species is also possible as a function of selected variables, such as the initial concentration or the volume of a given reagent.