Physical chemistry is the study of macroscopic, atomic, subatomic, and particulate phenomena in chemical systems in terms of physical laws and concepts. It applies the principles, practices and concepts of physics such as Stoichiometry, Heat Transfer, Entropy, Chemical Equilibrium, Electron Transfer, Chemical, Reactions. This book will develop in the student an understanding of the principles of physical further study of chemistry. In order to make the subject simple and interesting every topic included in this book has been self-sufficient in itself and has been explained in the light of modern development in a simple and elegant style. Every effort has been made in the representation manner in this book so that the students do not get confused while going through this book. The book helps the student in overall self assessment and prompts him to practice and review the gap areas in his learning process.