Entropy Change

Definition

Entropy change is a measure of the disorder or randomness that occurs in a system during a process or transformation. It is a fundamental concept in thermodynamics that describes the tendency of a system to move towards a more disordered state over time.

5 Must Know Facts For Your Next Test

1. Entropy change is a measure of the increase or decrease in the disorder or randomness of a system during a process or transformation.
2. Positive entropy change indicates an increase in disorder, while negative entropy change indicates a decrease in disorder.
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 expansion of a gas or the mixing of two liquids, are characterized by an increase in the entropy of the system.
5. Entropy change is a key concept in understanding the direction and feasibility of chemical and physical processes, as well as the efficiency of energy conversions.

Review Questions

• Explain how the concept of entropy change is related to 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 spontaneous processes, which are characterized by an increase in the disorder or randomness of the system, are favored. Entropy change is a measure of this increase or decrease in disorder, and it is a key concept in understanding the direction and feasibility of chemical and physical processes.
• Describe the relationship between entropy change and the spontaneity of a process.
  • Spontaneous processes are those that occur naturally without the input of external energy, and they are characterized by an increase in the entropy of the system. Positive entropy change indicates an increase in disorder, which is the driving force behind spontaneous processes. Conversely, negative entropy change indicates a decrease in disorder, which is less likely to occur spontaneously. The direction and feasibility of a process can be determined by evaluating the entropy change associated with that process.
• Analyze how entropy change can be used to understand the efficiency of energy conversions.
  • Entropy change is a key concept in understanding the efficiency of energy conversions, as it reflects the degree of disorder or randomness in the system. Processes that result in a large increase in entropy, such as the conversion of high-quality energy (e.g., electrical energy) into low-quality energy (e.g., heat), are generally less efficient. This is because a significant portion of the energy is lost to the environment, increasing the overall disorder of the system. Conversely, processes that minimize entropy change are typically more efficient, as they are able to convert energy with minimal loss to the surroundings. Understanding entropy change is crucial for designing and optimizing energy conversion systems to maximize their efficiency.

Related terms

Entropy: Entropy is a measure of the disorder or randomness in a system. It is a state function that represents the degree of disorder or uncertainty in a system.

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 Processes: Spontaneous processes are those that occur naturally without the input of external energy, and they are characterized by an increase in the entropy of the system.