In chemical engineering, theoretical foundations underpin the design, optimization, and operation of chemical processes across various industries. These encompass thermodynamics, governing energy transfer and chemical reactions; transport phenomena, analyzing momentum, heat, and mass transfer; reaction engineering, studying kinetics and reactor design; and process control, managing system dynamics and optimization. Additionally, materials science theories inform material selection and behavior in chemical processes. Environmental engineering theories address sustainability and pollution control. How do these theories collectively shape modern chemical engineering practice, addressing challenges like process efficiency, product quality, and environmental impact, while fostering innovation and sustainability in chemical processes worldwide?