thermodynamics an introduction and definitions

Thermodynamics is the science of the flow of heat. It applies to macroscopic systems in equilibrium and how to go from one equilibrium state to another. It is entirely empirical and summed up into four laws and basic mathematics.

Zeroth law of thermodynamics: defines temperature $ T$

First law of thermodynamics: defines energy $ U$

Second law of Thermodynamics: defines entropy $ S$

Third Law of Thermodynamics: gives numerical value to entropy $ S$

These laws are UNIVERSALLY VALID and cannot be circumvented.

Definitions used in Thermodynamics:

Examples of systems:

whatever is left over is the surroundings. Between the system and the surroundings is the boundary.

Examples of boundaries:

Systems can be:

Describing Systems requires:

Two classes of Properties:

A system is in equilibrium if the properties that describe the system, such as $ P$ , $ T$ , $ V$ , etc. do not change in time or space. A gas in a container needs to be the same $ P$ , $ T$ , $ V$ to be in equilibrium.

References

This is a derivative work from [1] a Creative Commons Attribution-Noncommercial-Share Alike 3.0 work

[1] MIT OpenCourseWare, 5.60 Thermodynamics and Kinetics: Thermodynamics and Kinetics, Spring 2008



Contributors to this entry (in most recent order):

As of this snapshot date, this entry was owned by bloftin.