ΔS

Definition

ΔS, or change in entropy, is a fundamental concept in thermodynamics that quantifies the disorder or randomness of a system. Entropy is a measure of the dispersal of energy within a system, and the change in entropy (ΔS) represents the difference in the entropy of a system before and after a process or transformation has occurred.

5 Must Know Facts For Your Next Test

1. The change in entropy (ΔS) is a measure of the increase or decrease in the disorder or randomness of a system during a process or transformation.
2. A positive ΔS indicates an increase in entropy, while a negative ΔS indicates a decrease in entropy.
3. The second law of thermodynamics states that the entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.
4. Spontaneous processes, such as the diffusion of a gas or the mixing of two liquids, are characterized by an increase in the entropy of the universe.
5. The change in entropy (ΔS) is a key factor in determining the spontaneity and feasibility of a process or transformation.

Review Questions

• Explain the relationship between ΔS and the second law of thermodynamics.
  • The second law of thermodynamics states that the entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium. This means that the change in entropy (ΔS) for a spontaneous process will be positive, as the system moves towards a more disordered or random state. The increase in entropy is a fundamental driving force behind the spontaneity of many natural processes, and the change in entropy (ΔS) is a key factor in determining the feasibility and direction of a process or transformation.
• Describe how ΔS can be used to predict the spontaneity of a process.
  • The change in entropy (ΔS) can be used to predict the spontaneity of a process or transformation. If the ΔS for a process is positive, the process is considered spontaneous and will occur naturally without the input of external energy. Conversely, if the ΔS for a process is negative, the process is considered non-spontaneous and will require the input of external energy to occur. The magnitude of the ΔS also provides information about the degree of spontaneity, with larger positive values indicating a more favorable, spontaneous process.
• Analyze how the change in entropy (ΔS) is related to the dispersal of energy within a system.
  • The change in entropy (ΔS) is directly related to the dispersal of energy within a system. As a system undergoes a process or transformation, the energy within the system becomes more dispersed, leading to an increase in the disorder or randomness of the system. This increase in disorder is quantified by the positive change in entropy (ΔS). The second law of thermodynamics states that the entropy of an isolated system not in equilibrium will tend to increase over time, reflecting the natural tendency of energy to become more dispersed and the system to become more disordered. The ΔS, therefore, provides a measure of the degree to which energy has become more dispersed within the system during a process or transformation.

Related terms

Entropy: Entropy is a measure of the disorder or randomness of a system. It represents the dispersal of energy within a system and is a key concept in the second law of thermodynamics.

Second Law of Thermodynamics: The second law of thermodynamics states that the entropy of an isolated system not in equilibrium will tend to increase over time, approaching a maximum value at equilibrium.

Spontaneous Process: A spontaneous process is a process that occurs naturally and without the input of external energy, and is characterized by an increase in the entropy of the universe.