Non-equilibrium thermodynamics

Definition

Non-equilibrium thermodynamics is the branch of thermodynamics that deals with systems that are not in thermodynamic equilibrium, meaning there are gradients in properties such as temperature, pressure, or chemical potential. This area focuses on understanding how systems evolve over time toward equilibrium and the associated fluxes and forces driving these processes. It plays a crucial role in explaining phenomena like transport processes and chemical reactions that occur away from equilibrium.

5 Must Know Facts For Your Next Test

1. Non-equilibrium thermodynamics extends traditional thermodynamic principles to systems where gradients exist, leading to fluxes of energy and matter.
2. The Boltzmann equation is fundamental in describing how particle distributions evolve in non-equilibrium states, addressing how particles interact and collide.
3. Onsager relations are critical for understanding the reciprocal relationships between different fluxes and forces in non-equilibrium systems, allowing predictions about their behavior.
4. Non-equilibrium thermodynamics can explain biological processes, such as cellular metabolism, where systems maintain order by dissipating energy from their surroundings.
5. In this field, the concepts of irreversible processes and time-dependent behavior contrast sharply with equilibrium thermodynamics, which assumes a static state.

Review Questions

• How does the Boltzmann equation relate to non-equilibrium thermodynamics in terms of particle dynamics?
  • The Boltzmann equation provides a statistical description of how the distribution of particles evolves over time in non-equilibrium thermodynamics. It accounts for interactions among particles, including collisions that change momentum and energy. By solving the Boltzmann equation, one can understand how these dynamics lead to phenomena such as diffusion and thermal conductivity, illustrating how systems move toward equilibrium through complex microstates.
• Discuss the significance of Onsager relations in the context of non-equilibrium thermodynamics.
  • Onsager relations are essential because they establish a link between different thermodynamic fluxes and forces in non-equilibrium systems. These relations imply that certain fluxes are proportional to the driving forces acting on them and also provide a framework for predicting how changes in one aspect of a system (like temperature or concentration) affect others. This reciprocal nature helps in understanding complex interactions in systems far from equilibrium, making it a powerful tool for analyzing transport phenomena.
• Evaluate the implications of non-equilibrium thermodynamics for biological systems, especially regarding energy dissipation.
  • Non-equilibrium thermodynamics has profound implications for biological systems, particularly in explaining how organisms maintain order and functionality despite being far from equilibrium. For example, cells convert chemical energy into work while dissipating heat and waste products. This energy dissipation is essential for sustaining life processes like metabolism and cellular signaling. Understanding these principles helps elucidate how life exists at the edge of chaos, enabling organisms to adapt and evolve within fluctuating environments.

Related terms

Entropy Production: The measure of the irreversible processes occurring in a system, which quantifies how much energy is dispersing and unavailable for doing work.

Fluctuation Theorem: A principle that provides insights into the probability distributions of entropy production in small systems over short time scales, even when they are out of equilibrium.

Nonequilibrium Steady State: A condition where a system remains in a steady state while continuously exchanging energy and matter with its surroundings, maintaining gradients that drive processes.