How entropy is a function of temperature and phase change and what does the enthalpy change ∆ H and entropy change ∆ S indicate?
The state of randomness or disorder in the molecules is called entropy. It measures the state of randomness or measure of disorder. During the phase transition, the temperature remaining constant impacts the entropy. Hence, the increase in the temperature even increases the overall rate of entropy. The change in enthalpy, denoted as Delta H, is the change in energy of a system. At constant pressure, this is simply the heat that is exchanged between a system and its surroundings. The change in entropy, denoted as Delta S, represents the change in randomness, or disorder of a system.
Entropy (S) is a fundamental concept in thermodynamics that describes the degree of disorder or randomness in a system. It is often referred to as a measure of the system's "microscopic configurations" or the number of ways in which the system's particles or components can be arranged.
Entropy is related to temperature and phase change through the Second Law of Thermodynamics, which states that the entropy of an isolated system tends to increase over time or remain constant in equilibrium. The specific relationship between entropy and temperature depends on the context and the system under consideration.
On the other hand, during a phase change from a gas to a liquid or a liquid to a solid, the entropy generally decreases. This is because the particles become more constrained in their movement, resulting in fewer available configurations and lower disorder.
Enthalpy change (ΔH) and entropy change (ΔS) are thermodynamic quantities that provide information about the energy and disorder changes associated with a process.
The relationship between ∆H and ∆S is described by the Gibbs free energy equation:
ΔG = ΔH - TΔS
where ΔG is the change in Gibbs free energy and T is the temperature. This equation shows that both enthalpy change and entropy change contribute to the overall change in free energy (∆G) of a system, and temperature plays a role in determining the direction and spontaneity of a process.
In summary, entropy is influenced by temperature and phase change, and it reflects the degree of disorder or randomness in a system. Enthalpy change (∆H) represents the heat absorbed or released during a process, while entropy change (∆S) indicates the change in disorder or randomness associated with the process.
The change in enthalpy, denoted as Delta H, is the change in energy of a system. At constant pressure, this is simply the heat that is exchanged between a system and its surroundings. The change in entropy, denoted as Delta S, represents the change in randomness, or disorder of a system. If both ΔH0 and ΔS0 are positive then reaction will be spontaneous at high temperature. Reactions are favorable when they result in a decrease in the enthalpy and an increase in the entropy of the system. When both of these conditions are met, the reaction is said to be spontaneous at all temperatures. If ΔH and ΔS are both positive, ΔG will only be negative above a certain threshold temperature and we say that the reaction is only spontaneous at 'high temperatures. Change in entropy is also a function of temperature, at any temperature, the entropy change can be given as: ΔS=∫dqT. Q. The entropy change can be calculated by using the expression ΔS=qrevT. (Normally though, CP=CP (T).) From this we can say that enthalpy and entropy change proportionally to a change in temperature. Heat added to a system at a lower temperature causes greater randomness than in comparison to when heat is added to it at a higher temperature. Thus, the entropy change is inversely proportional to the temperature of the system.
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