$"$In the realm of chemical engineering, theories serve as the backbone for understanding and optimizing processes that govern the transformation of matter. These theories draw upon principles from chemistry, physics, and mathematics to elucidate the behavior of materials and reactions at various scales, from molecular interactions to industrial$-$scale operations. Key theoretical frameworks include thermodynamics, transport phenomena, kinetics, and process control, each offering unique insights into the underlying mechanisms driving chemical processes. How do these theoretical foundations inform the design of efficient and sustainable processes, the development of novel materials, and the advancement of technologies crucial for addressing global challenges in energy, environment, and healthcare?"