Kapitel 20
The First Law of Thermodynamics
Thermodynamische Systeme
A thermodynamic system is a set of objects whose thermodynamic properties are of interest. The system is considered to be embedded in its surroundings or ...
Geleistete Arbeit während der Lautstärkeänderung
In mechanics, work is done on an object when the force acting on it displaces the object. In thermodynamics, work done on a system can be estimated when ...
Pfad zwischen thermodynamischen Zuständen
Consider the two thermodynamic processes involving an ideal gas that are represented by paths AC and ABC in Figure 1:
In the first process for path A to ...
Wärme und freie Ausdehnung
The work done by a thermodynamic system depends not only on the initial and final states but also on the intermediate states—that is, on the path. ...
Innere Energie
The internal energy of a thermodynamic system is the sum of the kinetic and potential energies of all the molecules or entities in the system. The kinetic ...
Erster Hauptsatz der Thermodynamik
A change in the internal energy of a system depends on the the net heat transfer into the system and the net work done by the system. The first law of ...
Erster Hauptsatz der Thermodynamik: Problemlösung
The first law of thermodynamics states that the change in internal energy of the system is equal to the net heat transfer into the system minus the net ...
Zyklische Prozesse und isolierte Systeme
A thermodynamic system with zero heat exchange and work is an isolated system. For these systems, the internal energy remains constant.
In the case of a ...
Isotherme Prozesse
A thermodynamic process that occurs at constant temperature is called an isothermal process. Heat slowly flows into the system or out of the system to ...
Isochore und isobare Prozesse
A thermodynamic process that occurs at constant volume is called an isochoric process. According to the first law of thermodynamics, heat supplied or ...
Wärmekapazitäten eines idealen Gases I
Heat capacity is the ratio of heat absorbed by the substance corresponding to its temperature change. It is also called thermal capacity and the SI unit ...
Wärmekapazitäten eines idealen Gases II
For a system that undergoes a thermodynamic process at a constant volume condition, the heat absorbed is used only to increase the system's internal ...
Wärmekapazitäten eines idealen Gases III
The number of independent ways a gas molecule can move along straight line, rotate, and vibrate is called its degrees of freedom. Supposing d represents ...
Adiabatische Prozesse für ein ideales Gas
When an ideal gas is compressed adiabatically, that is, without adding heat, work is done on it, and its temperature increases. In an adiabatic expansion, ...
Druck und Volumen in einem adiabatischen Prozess
Free expansion of a gas is an adiabatic process. However, there are few differences between free expansion and adiabatic expansion. During free expansion, ...
Arbeiten in einem adiabatischen Prozess
Consider the adiabatic compression of an ideal gas in the cylinder of an automobile diesel engine. The gasoline vapor is injected into the cylinder of an ...
Thermodynamische Potentiale
Thermodynamic potentials are state functions that are extremely useful in analyzing a thermodynamic system. They have dimensions of energy. The four ...
Thermodynamische Beziehungen nach Maxwell
Maxwell's thermodynamic relations are very useful in solving problems in thermodynamics. Each of Maxwell's relations relates a partial ...
Joule-Thomson-Effekt
The Joule-Thomson effect, also known as the Joule-Kelvin effect, describes the temperature change of a fluid when it is forced through a valve or porous ...
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