the fundamental principles governing mass and energy transfer, thermodynamics, reaction kinetics, and transport phenomena. Investigate how these theories underpin the design, optimization, and operation of various chemical processes, from traditional petroleum refining to cutting$-$edge biotechnology and nanomaterials production. Discuss the interdisciplinary nature of chemical engineering, incorporating principles from chemistry, physics, mathematics, and biology. Highlight the role of computational modeling and simulation in advancing theoretical frameworks and driving technological advancements. Ultimately, analyze how a deep understanding of these theories drives sustainable development and addresses global challenges in energy, environment, and health.