In chemical engineering, the foundation lies in the principles of chemistry, physics, and mathematics applied to the design, operation, and optimization of processes that transform raw materials into valuable products. At its core, chemical engineering employs theories from thermodynamics, fluid mechanics, heat and mass transfer, reaction kinetics, and process control to address challenges in various industries such as pharmaceuticals, petroleum refining, materials synthesis, and environmental engineering. Theoretical frameworks enable engineers to understand the behavior of materials and substances at different scales, from molecular interactions to industrial$-$scale processes. These theories guide the design of efficient and sustainable processes, ensuring safety, cost$-$effectiveness, and environmental responsibility in the production of chemicals, fuels, pharmaceuticals, and other essential products.