The practice problems provided as part of this text are chiefly interactive, and should provide a useful assessment of the reader's understanding at various stages in the development of the subject. Some of these problems make use of a Molecular Editor drawing application created by Peter.Ertl. To practice using this editor Click Here. Since problem solving is essential to achieving an effective mastery of the subject, it is recommended that many more problems be worked. Most organic chemistry textbooks contain a broad assortment of suitable problems, and paperback collections of practice problems are also available. In addition, a large collection of multiple choice problems may be viewed Here . The following button will activate a collection of problems concerning the reactivity of common functional groups. The following web-sites provide nice collections of problems and answers: Towson University-reaction quizzes and summaries Ohio State University-electronic flashcards University of Wisconsin-concept questions UCLA-helpful advice Notre Dame-spectroscopy problems For a useful collection of study materials, including links to other sites, visit the Organic chemistry tool-kit . Prepared by Bob Hanson, St. Olaf College