Thermodynamic potentials Simulations

Thermodynamic potentials Simulations Visually

Master Thermodynamic potentials with interactive visualizations. Understand Helmholtz free energy, Gibbs free energy, enthalpy, and internal energy through hands-on simulations and real-world examples.

Thermodynamic potentials Internal Energy Helmholtz Free Energy Gibbs Free Energy Enthalpy State Functions Visual Simulation

What are Thermodynamic potentials?

Thermodynamic potentials are state functions that represent the energy content of a system under specific constraints. They are crucial for determining the equilibrium states of systems and predicting the direction of spontaneous processes. Each potential is minimized under certain conditions, making them powerful tools for analyzing thermodynamic systems.

These potentials provide different perspectives on the energy landscape of a system, depending on which variables (pressure, volume, temperature, entropy) are held constant. Understanding these relationships is essential for predicting system behavior in various physical and chemical processes.

Interactive potentials Simulator

Potential Visualization

Observe how different thermodynamic potentials change with system parameters. The visualization shows energy landscapes and their minimization under different constraints.

Potential Controls

Internal Energy (U)
Enthalpy (H)
Helmholtz (F)
Gibbs (G)
Temperature
300 K
Pressure
5 atm
Volume
5 L
Potential Information

Select a potential to view detailed information about its definition, mathematical formulation, and physical significance.

Understanding Thermodynamic potentials

Internal energy is the total energy contained within a thermodynamic system, including kinetic energy of molecules and potential energy from molecular interactions. It is a fundamental state function that depends only on the current state of the system.

dU = TdS - PdV

Key Characteristics:

  • Extensive property (depends on system size)
  • Cannot be directly measured, only changes
  • Natural variables: Entropy (S) and Volume (V)
  • Minimized at constant entropy and volume

Applications: Foundation for all other thermodynamic potentials, energy balance calculations in closed systems.

Enthalpy is a thermodynamic potential that represents the total heat content of a system. It is particularly useful for processes occurring at constant pressure, such as many chemical reactions in open containers.

H = U + PV

dH = TdS + VdP

Key Characteristics:

  • Extensive property
  • Natural variables: Entropy (S) and Pressure (P)
  • Minimized at constant entropy and pressure
  • Change equals heat transfer at constant pressure

Applications: Chemical reactions, phase transitions, calorimetry, HVAC systems.

Helmholtz free energy is a thermodynamic potential that measures the useful work obtainable from a closed system at constant temperature and volume. It represents the maximum amount of work that can be extracted from a system.

F = U - TS

dF = -SdT - PdV

Key Characteristics:

  • Extensive property
  • Natural variables: Temperature (T) and Volume (V)
  • Minimized at constant temperature and volume
  • Decrease indicates spontaneous process at constant T,V

Applications: Statistical mechanics, phase transitions, chemical reactions at constant volume.

Gibbs free energy is the most commonly used thermodynamic potential, representing the maximum reversible work that can be performed by a system at constant temperature and pressure. It determines the spontaneity of chemical reactions and phase transitions.

G = H - TS = U + PV - TS

dG = -SdT + VdP

Key Characteristics:

  • Extensive property
  • Natural variables: Temperature (T) and Pressure (P)
  • Minimized at constant temperature and pressure
  • Negative change indicates spontaneous process at constant T,P

Applications: Chemical reactions, biochemical processes, phase equilibria, electrochemistry.

Relationships Between potentials

Understanding how thermodynamic potentials relate to each other through Legendre transformations.

Potential Transformations

Legendre Transformations:

  1. From Internal Energy (U): Add PV term to get Enthalpy (H = U + PV)
  2. From Internal Energy (U): Subtract TS term to get Helmholtz Free Energy (F = U - TS)
  3. From Enthalpy (H): Subtract TS term to get Gibbs Free Energy (G = H - TS)
Key Insight:

Legendre transformations allow us to change the natural variables of a thermodynamic potential, making different constraints more convenient to work with mathematically.

Potential Comparison Chart

Real-world Applications

Chemical Reactions

Gibbs free energy determines whether chemical reactions will proceed spontaneously. Negative ΔG indicates a spontaneous reaction under standard conditions.

Phase Transitions

Thermodynamic potentials help predict phase transitions. At phase boundaries, the relevant potentials of coexisting phases are equal.

Battery Technology

Gibbs free energy determines the maximum electrical work a battery can perform. Battery design optimizes this energy conversion.

Data Export & Import

Save your potential simulation data or load previous experiments for further analysis.

Download CSV file with potential parameters and results
Upload previously exported data for analysis