Chemical Transformation in Far-from-Equilibrium Systems

In this chapter we present a brief overview of chemical transformationsChemical transformations from a thermodynamic perspective, especially involving open systemsOpen systems. In open systems, energyEnergy and mass flow in and out of the boundary surrounding the system, and thermodynamic equilibrium is not maintained. However, nonequilibrium systems may reach steady states where the rates of change of mass, energy and entropyEntropy are zero. These states are called nonequilibrium steady statesNonequilibrium steady states (NESS), which show an order in chemically reactive systems. We discuss chemical transformations (reactions) in thermodynamic equilibrium systems first to understand the mechanisms leading to different behaviors and to introduce pertinent concepts such as entropy production related to irreversibleIrreversible processesProcesses so that we set the context for the later chapters. Especially dual role of irreversible processes in creating order through fluctuationsFluctuations in nonequilibrium systems leading to dissipative structuresDissipative structures, and in destroying order in near equilibrium systems is discussed. It is important to note that fluctuations play a fundamental role in determining the states of the systems, and chemical speciesChemical species especially in small systems such as in cells exist in noisy environments due to crowdedness, low copy numbers and porous boundary conditions: Hence the justification for stochastic approaches within a white noise mathematical framework.