18. Basic Laws and Concepts of Thermodynamicsrename
yaboiemil's version from 2016-02-04 19:22
|Classical Thermodynamics||Not concerned with the microstructure of the system. Considered a continuum.|
|Statistical Thermodynamics||Concerned with the microstructure of the system.|
|Isolated System||Exchange neither matter nor energy with surroundings|
|Closed system||Exchange only energy with the surroundings|
|Open system||Exchange matter and energy with the surroundings|
|State Variables||Physical variables needed to describe a system. Remain at ZERO if a reversible thermodynamic cycle occurs.|
|Local or Intensive State Variables||Variables that remain identical throughout parts of the system (e.g. temp or pressure)|
|Extensive or Additive or Global State Variables||Variables that are valid for the whole system, sum of values for individual parts (internal energy or volume)|
1. A Reversible Process is a process where the changes are infintesimal. If you reverse signs of changes, process is reversed.
2. Irreversible Process is a sequence of non-equilibrium states. A reversal of signs will not reverse the process, because some
of the variables were unknown or non equilibrium.
3. Work can be done on a system by surroundings, and the system can do work on its surroundings.
Mechanical Work in a System
|Δs||Change in position or trajectory|
|ΔV||Change in Volume|
4. Negative work can occur, when the volume decreases, as the surroundings are doing work on the system
5. Positive work occurs when the system does work on the surroundings, and the volume increases.
6. The total work of a system from one V to another
7. Temperature and Heat is not the same thing.
|Temperature||Average kinetic energy of microscopic motions of a single particle.|
|Heat||The physical property that determines heat flow.|
|Heat flow||The flow of heat energy between 2 objects... Hotter to Colder.|