Thermodynamics micro and macroscopic aspects

Thermodynamics: micro and macroscopic aspects

Thermodynamics is the tool of choice for studying matter at the 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 degree program, the principles of thermodynamics and their direct application to chemistry are described in the case of simple single-phase equilibrium reactions or between homogeneous phases. This teaching unit will deepen this knowledge in two directions.

First of all, this framework of macroscopic thermodynamic description will be generalized 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. Breakdowns and equilibrium displacements will also be studied.

Then we will focus on the link with the microscopic world where matter is described at the atomic scale. We will show that the evolution predicted by thermodynamics is of a statistical nature, the equilibrium state thus corresponding to the most probable macroscopic state given the constraints applied to the system. This will allow to deduce from the microscopic description of a physico-chemical system its macroscopic thermodynamic properties.

To be able to describe the chemical reaction by a set of relevant macroscopic parameters

Use of standard thermodynamic data to predict the evolution of simple systems

Application to interfaces and inhomogeneous media

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

Understand the equilibrium between phases and know how to predict the associated macroscopic laws

Know 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 by microscopic analysis, based on the canonical or microcanonical set

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

Students enrolled in this module must have previously taken the courses of : L2 Chemistry or equivalent level

Final test

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