Process modeling (chemical engineering) is the systematic development and application of mathematical representations to describe, simulate, and predict the behavior of chemical processes and systems. These models encapsulate the underlying physical, chemical, and thermodynamic principles governing phenomena such as mass transfer, energy transfer, momentum transfer, reaction kinetics, and phase equilibria within process units like reactors, separation equipment (relevant to chemical engineering separations), and heat exchangers, or across integrated plants. The models are typically formulated as systems of algebraic and differential equations. The significance of process modeling lies in its utility for process design, analysis, optimization, and control (relevant to process control), facilitating enhanced understanding, improved efficiency, safety, sustainability, and profitability in the chemical and process industries.