The present textbook is written for undergraduate students of chemical engineering as per the syllabus framed by AICTE curriculum. It explains the basic chemical process principles in a lucid manner. SI units, chemical stoichiometry and measures of composition, behaviour of gases, vapour pressure of pure substances, and humidity and saturation are covered in detail. In addition, mass and energy balances of chemical processes have also been described. Chemical processes without chemical reactions include fluid flow, mixing, evaporation distillation, absorption and stripping, liquid