Following the Extent of a Reaction with the Help of Maple
Inmaculada Suárez and Baudilio Coto
Department of Chemical and Environmental Technology, ESCET, Rey Juan Carlos University, C/Tulipán, 28933 Móstoles, Madrid, Spain
The use of Maple allows a numerical and graphical procedure to display values of thermodynamic magnitudes along the progress of a chemical reaction. Such magnitudes are related with the spontaneity of the system composition change and, when they are studied for intermediate mixtures, they allow one to understand whether reaction proceeds further and the meaning of the equilibrium composition finally reached. The advantages of using Maple are both to find the numerical solution of equations and to represent graphically functions against the extent of reaction. Details about calculation procedure, mainly those related with Maple formulation of thermodynamic equations, are included. This document is focused on the ammonia production reaction. In the first example, the equilibrium composition is calculated and the meaning of the change in the values of G, ΔrG and QP is analyzed through plots of these thermodynamic quantities as a function of the extent of reaction. In the second example, the effect of pressure and temperature is shown through the change in the plot of G versus ξ (the extent of the reaction), which can be related to the values of ξ at equilibrium under the different conditions.
Gibbs energy as a function of the extent of a reaction (shown as xi/mol) for the formation of ammonia.
Our Secondary School editors work hard to distill all the JCE materials to produce a fraction of particular interest to high school teachers. We call it CLIC.
In recent years we have worked hard to better match our advertisers with our readers. When shopping for chemistry education materials, visit our advertisers' WWW sites first.
Take JCE along on your outreach missions. Copies of the Journal, guest access to JCE Online, our publications catalog, and more are available for your participants.