Foundational theories in chemical engineering encompass thermodynamics, transport phenomena, reaction kinetics, and process control. Thermodynamics elucidates energy transfer and equilibrium in chemical processes. Transport phenomena analyze mass, momentum, and energy transfer in fluids and solids. Reaction kinetics study the rates and mechanisms of chemical reactions. Process control regulates and optimizes industrial processes. Together, these theories provide the framework for designing, analyzing, and optimizing chemical processes in various industries, from petroleum refining to pharmaceutical production.