Download Introduction to Thermodynamics and more Lecture notes Thermodynamics in PDF only on Docsity! Invitation to Thermodynamics Thermodynamics is a branch of science that concerned with the macroscopic (in some sense measurable) properties of systems on which observations are made, independent of their microscopic composition. Laws of thermodynamics are applicable over extremely wide range of scientific disciplines – Engineering (mechanical, chemical . . .), Chemistry, Biology, classical and quantum Physics, Cosmology, Atmospheric sciences, Information theory and so on. It is an axiomatic approach, pretty much like Euclid’s geometry. Begin with some definitions – System – object of interest on which observations are carried out. We can measure relevant quantities like pressure, temperature, modulii of elasticity, magnetism etc. Surroundings – any other things that are not observed or under measurement. System may interact with or remain isolated from the surroundings. Boundary – A wall that separates system from the surroundings. Depending on properties of wall, it may or may not allow system to interact with the surroundings. Thermodynamic equilibrium – An equilibrium state in which the bulk physical properties of a system do not changes with time and are uniform throughout the system. Equilibrium can be mechanical (equal pressure), thermal (equal temperature) or chemical (equal chemical potentials) . Isolated system – System cannot exchange anything whatsoever including energy and matter. System may not be in equilibrium with surroundings. Closed system – System cannot exchange matter but may exchange energy with the surroundings. System can be in thermal equilibrium with the surroundings. Open system – System can exchange matter and energy with the surroundings and can reach equilibrium with it. Whether or not the system is in thermal equilibrium with other system(s) or the surroundings depends on the nature of the wall that separates the system from the other system(s) or surroundings. Adiabatic wall – A thermally insulating wall that does not allow exchange of energy (or heat) among systems. Diathermal wall – A thermally conducting wall that allow exchange of energy (or heat) among systems.
