This college-preparatory laboratory science is primarily for juniors and seniors. Topics covered include atomic theory, phase changes, origins and significance of the periodic chart, quantum mechanics, chemical reactions, acid-base relationships, oxidation-reduction principles, and an expanded section on organic chemistry. Whenever possible, discussions are geared to helping students gain an understanding of the principles and mechanics of natural phenomena as well as modern technological advances. The laboratory portion of the course has been designed to illustrate chemical principles and to develop the critical thinking and problem-solving skills of the students. This is accomplished by starting with simple questions about chemistry and requiring students to develop the procedure for each laboratory experiment that they perform. As students develop their methods and become familiar with the lab, the questions become progressively more challenging.