Lecture

Thermodynamic Functions and State Variables

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In course

PHYS-106(a): General physics : thermodynamics

Le but du cours de Physique générale est de fournir les notions de base nécessaires à la compréhension des phénomènes physiques. L'objectif est atteint lorsqu'il est possible de prévoir quantitativement les conséquences de ces phénomènes avec des outils th ...

Description

This lecture covers the concept of state variables and thermodynamic functions, discussing the choice of state variables and elastic and calorimetric coefficients. It also explores the differential of a function of multiple variables, the fundamental relation of thermodynamics, and the Legendre transformation to create new functions. Different functions like internal energy, enthalpy, free energy, and Gibbs free energy are analyzed in terms of their suitability for specific variables. The lecture emphasizes the importance of selecting appropriate state functions and variables for studying thermodynamic systems.

Instructors (2)

Romuald Houdré

Curriculum Vitae CV 2011 Appointed as Adjunct Professor 2006 Appointed as Maitre d'Enseignement et de Recherche 2004 Joins the "Laboratory of Quantum Electronics" led by Prof. B. Deveaud-Plédran 2001-2004 Appointed as "Adjoint Scientifique" at the Institute for Quantum Photonics and Electronics (previously Institute for Micro and Optoelectronics led by Prof. M. Ilegems) 1998 Habilitation, University Pierre et Marie Curie, Paris 6 (France) 1997 Invited researcher at NTT, Optoelectronics Department (Atsugi, Japan) 1988-2000 "Collaborateur scientifique" at the Institut for Micro and Optoelectronics with Prof. M.Ilegems at the Swiss Federal Institut of Technology in Lausanne (Switzerland). In charge of the Molecular Beam Epitaxy (1988-1996) and the research on optical microcavities (1996-2000) 1987-1988 Laboratoire de Physique de la Matière Condensée at Ecole Polytechnique (France). 1986-1987 Postdoctoral fellow at the University of Illinois at Urbana-Champaign (U.S.A.) with Prof. H.Morkoç in the molecular beam epitaxy group 1983-1985 Ph.D. thesis on the photoemission from quantum wells and superlattices under negative electron affinity at Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique (France), G.Lampel and C.Hermann as advisors

Cécile Hébert

Cécile Hébert was born in France in 1970. She obtained her Ingeneer degree (physics) and her PhD degree (design of a new energy filter for transmission electron microscopy, under the direction of Prof. B. Jouffrey) at the Ecole Centrale in Paris. As a post doc with Prof. P. Schattschneider, she was working on the calculation of the fine structure of ionisation edges in EELS. As a research assistant at the Vienna University of Technology, she was one of the main participant to the CHIRALTEM project dealing with the measurement of magnetic circular dichroism in the electron microscope.

Official source

Ontological neighbourhood

Physics

Thermodynamics: Statistical mechanics

Related concepts (32)

Thermodynamics

Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of thermodynamics which convey a quantitative description using measurable macroscopic physical quantities, but may be explained in terms of microscopic constituents by statistical mechanics.

Gibbs free energy

In thermodynamics, the Gibbs free energy (or Gibbs energy as the recommended name; symbol ) is a thermodynamic potential that can be used to calculate the maximum amount of work, other than pressure-volume work, that may be performed by a thermodynamically closed system at constant temperature and pressure. It also provides a necessary condition for processes such as chemical reactions that may occur under these conditions. The Gibbs free energy is expressed as where p is pressure, T is the temperature, U is the internal energy, V is volume, H is the enthalpy, and S is the entropy.

Thermodynamic state

In thermodynamics, a thermodynamic state of a system is its condition at a specific time; that is, fully identified by values of a suitable set of parameters known as state variables, state parameters or thermodynamic variables. Once such a set of values of thermodynamic variables has been specified for a system, the values of all thermodynamic properties of the system are uniquely determined. Usually, by default, a thermodynamic state is taken to be one of thermodynamic equilibrium.

Helmholtz free energy

In thermodynamics, the Helmholtz free energy (or Helmholtz energy) is a thermodynamic potential that measures the useful work obtainable from a closed thermodynamic system at a constant temperature (isothermal). The change in the Helmholtz energy during a process is equal to the maximum amount of work that the system can perform in a thermodynamic process in which temperature is held constant. At constant temperature, the Helmholtz free energy is minimized at equilibrium.

Thermodynamic free energy

In thermodynamics, the thermodynamic free energy is one of the state functions of a thermodynamic system (the others being internal energy, enthalpy, entropy, etc.). The change in the free energy is the maximum amount of work that the system can perform in a process at constant temperature, and its sign indicates whether the process is thermodynamically favorable or forbidden. Since free energy usually contains potential energy, it is not absolute but depends on the choice of a zero point.

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