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Chapitre 17

Thermodynamique

Spontanéité de la réaction
Spontanéité de la réaction
A spontaneous process is one that occurs naturally under certain conditions. A nonspontaneous process, on the other hand, will not take place unless it is ...
Entropie
Entropie
Salt particles that have dissolved in water never spontaneously come back together in solution to reform solid particles. Moreover, a gas that has ...
Deuxième loi de la thermodynamique
Deuxième loi de la thermodynamique
In the quest to identify a property that may reliably predict the spontaneity of a process, a promising candidate has been identified: entropy. Processes ...
Troisième loi de la thermodynamique
Troisième loi de la thermodynamique
A pure, perfectly crystalline solid possessing no kinetic energy (that is, at a temperature of absolute zero, 0 K) may be described by a single ...
Changement d'entropie standard pour une réaction
Changement d'entropie standard pour une réaction
Entropy is a state function, so the standard entropy change for a chemical reaction (ΔS°rxn) can be calculated from the difference in standard ...
Enthalpie libre
Enthalpie libre
One of the challenges of using the second law of thermodynamics to determine if a process is spontaneous is that it requires measurements of the entropy ...
Effets de la température sur l'enthalpie libre
Effets de la température sur l'enthalpie libre
The spontaneity of a process depends upon the temperature of the system. Phase transitions, for example, will proceed spontaneously in one direction or ...
Calcul des variations d'enthalpie libre standard
Calcul des variations d'enthalpie libre standard
The free energy change for a reaction that occurs under the standard conditions of 1 bar pressure and at 298 K is called the standard free energy change. ...
Variations d'enthalpie libre pour les états non standard
Variations d'enthalpie libre pour les états non standard
The free energy change for a process taking place with reactants and products present under nonstandard conditions (pressures other than 1 bar; ...
Enthalpie
 libre et équilibre
Enthalpie libre et équilibre
The free energy change for a process may be viewed as a measure of its driving force. A negative value for ΔG represents a driving force for the ...
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