How do chemical engineers apply theoretical principles such as thermodynamics, kinetics, and transport phenomena in various industries like pharmaceuticals, petrochemicals, and materials manufacturing? Discuss the integration of these theories to analyze reaction mechanisms, design reactors, and control process variables. Explore the role of computational modeling and simulation techniques in predicting system behavior and guiding experimental investigations. Additionally, investigate how chemical engineers utilize principles of mass and energy balances to develop efficient separation processes and minimize environmental impact. Evaluate the significance of theoretical understanding in addressing contemporary challenges like sustainable production and resource utilization in the field of chemical engineering.