Micro and macroscopic aspects of thermodynamics

Thermodynamics: micro and macroscopic aspects

Thermodynamics is the tool of choice for studying matter on a macroscopic scale. In particular, in the case of chemical reactions, it allows us to predict the direction of their evolution and their state of equilibrium. In the first years of the bachelor's degree, we focus on describing the principles of thermodynamics and their direct application to chemistry in the case of simple single-phase equilibrium reactions or reactions between homogeneous phases. This teaching unit will deepen this knowledge in two directions.

First, we will generalize this macroscopic thermodynamic description framework to more complex systems, such as interfacial systems where surface tension plays a role, or non-uniform phases where the composition is not the same everywhere due to an external field. We will also study ruptures and equilibrium displacements.

Next, we will look at the link with the microscopic world, where matter is described at the atomic scale. We will show that the evolution predicted by thermodynamics is statistical in nature, with the state of equilibrium corresponding to the most probable macroscopic state given the constraints applied to the system. This will allow us to deduce the macroscopic thermodynamic properties of a physicochemical system from its microscopic description.

Be able to describe the chemical reaction using a set of relevant macroscopic parameters.

Using standard thermodynamic data to predict the evolution of simple systems

Application to interfaces and inhomogeneous media

Know the laws of moderation and how to apply them to chemical reactions

Understanding phase equilibria and predicting the associated macroscopic laws

Understand the practical physical meaning of temperature, pressure, and chemical potential.

Understanding the microscopic interpretation of the fundamental principle

Know how to calculate thermodynamic quantities for simple systems using microscopic analysis, based on the canonical or microcanonical ensemble.

Use these microscopic thermodynamic parameters (Boltzmann factor, density of states, etc.) to predict the experimental fluctuations of a system.

Students enrolled in this module must have previously completed the following courses: L2 Chemistry or equivalent level.

Terminal control

Mass Action Law, Affinity, chemical potential and electrochemical potential, entropy of the universe, Le Châtelier's principles, variance, statistical thermodynamics, mean value and most probable value