This book, entitled 'General Processes in Chemical Physics', comes from course notes given to undergraduate students over many years and in different universities. The understanding of the different concepts is made easier by numerous application examples, solved and commented on. The choice of the structure of this book was guided by the wish to make the different states of matter clearly understood ('Part I. From gas to liquid'), before tackling the experimental laws in solution, the solubility and the acid-base reactions' issues ('Part II. Experimental laws in solution'). The third part ("Part III. Thermochemistry") deals with elements of thermodynamics applied to chemical reactions. Many laws and empirical principles previously stated find their explanation in this chapter.