Diagramas de fase

A closer look at phase diagrams for the general chemistry Course

Stephen A. Gramsch

Geophysical laboratory and Center for High Pressure Research, Carnegie Institution of Washington, 5251 BroadBranch Road, NW, Washington, DC 20015; gramsch@gl.ciw.edu

During the year-long curse of general chemistry, students are introduced to a wide range of physicochemical principles, but there isusually insufficient time to probe some of the more interesting application of these constructs. Mastering the computational aspects of topics such as stoichiometry, equilibrium, thermodynamics, andkinetics requires a significant amount of class time as well as out-of- class preparation on the part of both students and instructors, and indeed, this time investment is crucial if students are to besuccessful both in the general course and in further studies in chemistry. Quite often, however , it is the qualitative aspects of the course that make chemistry interesting to students and kindle theirenthusiasm for science, because it is at these points in the development of the subject that they can finally allow themselves to relax, concentrate on the beauty of the science rather than the detailsof a rather arid calculation, and begin to adopt their own view of the subject matter rather than that of the instructor. In the ongoing debate concerning the structure of the general chemistrycurriculum, it is important to give attention to general, qualitative constructs because these often prove to be the most efficient and useful in illustrating general scientific ideas and in likingtogether different groups of ideas into a unified framework.

One very important set of physical principles that often severely underrepresented in general chemistry textbooks and course, but one that hasthe potential to tie together a number of lines of inquiry, is embodied in the phase diagrams of one component system. In fact, one of the most active fields of both basic and applied scientific...