Much research has been conducted regarding student alternative conceptions in chemistry, and a significant amount of work has focused on the areas of chemical equilibrium and reaction rates. Less research has focused on teachers' alternative conceptions in these areas, and most of this work has studied the conceptions of pre-service and novice chemistry teachers. Teachers' understanding of chemistry concepts, as well as the way they integrate these topics, play a crucial role in their ability to teach for understanding and promote conceptual change in their students. This study investigated experienced high school chemistry teachers' conceptions about chemical equilibrium as it relates to reaction rates. Thirteen teachers of advanced (AP and IB) chemistry, with an average of 11.4 years of experience, completed the Chemical Equilibrium Concepts Test (CECT, Hackling and Garnett, 1985), and participated in interviews containing graphing tasks. Information about each teacher's alternative conceptions regarding equilibrium and reaction rates was ascertained, as well as information about how these topics were integrated in their minds and in their classrooms. The teachers in the study maintained many of the same alternative conceptions held by students and pre-service/novice teachers. The concepts of reaction rates as they relate to chemical equilibrium were not well understood. The teachers had difficulty describing changes to an equilibrium system in terms other than the algorithmic statements of Le Chatelier's principle and were generally unable to draw accurate concentration and rate graphs for these changes. Those teachers who held primary certifications in chemistry were better able to describe equilibrium in terms of reaction rates, scored higher on the CECT, and maintained fewer alternative conceptions. The results of this study have important implications for chemistry education. A greater focus on the integration of chemistry topics is needed in textbooks and in course curricula. Teacher training and professional development should include courses that focus on mastering the nuances and interconnectedness of topics in chemistry, as well as a study of the research that has been conducted with respect to the alternative conceptions of both teachers and students. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]