Entropy Formula
Entropy is a scientific concept often associated with a state of disorder, randomness, or uncertainty. In the context of thermodynamics, entropy is related to the energy and temperature of a system, and it is represented by the equation
S = kb ln Ω
where,
- S is the Entropy
- kb is the Boltzmann Constant
- Ω is the number of microscopic configuration
Entropy Change Formula
The formula for calculating the change in entropy (ΔS) for a system depends on the type of process or reaction. Here are some standard formulas for entropy change:
Entropy Change General Formula: For a general case, where the process is not isothermal or isobaric, the entropy change can be calculated using the first law of thermodynamics:
ΔS= ΔQ/T
where,
- ΔQ is the heat absorbed or released by the system
- T is the absolute temperature
Isothermal Processes: For an isothermal process, such as the expansion of an ideal gas, the entropy change can be calculated using the following formula:
ΔS = nRln (V2/V1)
where,
- n is the number of moles
- R is the ideal gas constant
- V1 and V2 are the initial and final volumes, respectively.
Isobaric Process: For an isobaric process, such as a chemical reaction, the entropy change can be calculated using the following formula:
ΔS=∑ΔSproducts −∑ΔSreactant
where,
- ΔSproducts and ΔSreactants are the entropies of the products and reactants, respectively.
Unit of Entropy
Entropy has units of energy divided by temperature, which is represented as:
Joules per Kelvin (J/K)
This unit is derived from the Boltzmann constant, a fundamental physics constant that relates entropy to temperature and energy.
Dimension of Entropy
Dimensional Formula for Entropy is:
[ML2T−2K-1 ]
Entropy
Entropy means the amount of disorder or randomness of a system. It is a measure of thermal energy per unit of the system which is unavailable for doing work. The concept of entropy can be applied in various contexts and stages, including cosmology, economics, and thermodynamics. Entropy is a concept that essentially discusses the spontaneous changes that take place in ordinary phenomena or the Universe’s inclination towards disorder.
In this article, we will learn what is meaning of Entropy, the entropy change formula, and how it is associated with the laws of thermodynamics.
Table of Content
- What is Entropy?
- Properties of Entropy
- Entropy Formula
- Change in Entropy
- Entropy Changes During Phase Transition
- Entropy and Enthalpy