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Entropy is the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work. It is a fundamental concept in thermodynamics that quantifies the degree of disorder or randomness in a system.
The calculator uses the formula:
Where:
Explanation: This formula relates entropy to enthalpy, Gibbs free energy, and temperature, providing a way to calculate entropy when these thermodynamic properties are known.
Details: Calculating entropy is crucial for understanding thermodynamic processes, predicting spontaneity of reactions, and analyzing energy transformations in various systems.
Tips: Enter enthalpy and Gibbs free energy in joules, temperature in kelvin. Temperature must be greater than zero. All values must be valid numerical inputs.
Q1: What is the physical significance of entropy?
A: Entropy represents the degree of disorder or randomness in a system and is related to the number of microscopic configurations that correspond to a thermodynamic system's macroscopic state.
Q2: Why is temperature in the denominator?
A: Temperature appears in the denominator because entropy is defined as thermal energy per unit temperature, making it an intensive property.
Q3: What are typical units for entropy?
A: The SI unit for entropy is joules per kelvin (J/K). In some contexts, entropy is expressed in calories per kelvin or other energy/temperature units.
Q4: Can entropy be negative?
A: While the entropy change of a system can be negative (decrease in disorder), the absolute entropy of a system is always positive according to the third law of thermodynamics.
Q5: How does this relate to the second law of thermodynamics?
A: The second law states that the total entropy of an isolated system can never decrease over time, and is constant if and only if all processes are reversible.