Free energy G takes entropy S into account through the equation G = H - TS; even if the energy remains the same, the free energy can decrease due to an entropy increase.
The free energy (G) is a thermodynamic potential that incorporates both the enthalpy (H) and the entropy (S) of a system. The relationship is expressed by the equation G=H−TS, where T is the temperature. This equation reflects the balance between the energy content (enthalpy) and the degree of disorder or randomness (entropy) in a system.
Enthalpy represents the internal energy of the system, while entropy accounts for the system's randomness or the number of possible microscopic arrangements. The product TS in the equation reflects the energy associated with the system's disorder. The negative sign indicates that as entropy increases, the term TS becomes more significant, and the free energy (G) decreases.
Even if the total energy (enthalpy) remains constant, a decrease in free energy can occur if there is a corresponding increase in entropy. This implies that a system tends to move towards a state of lower free energy, often associated with increased disorder or randomness, as it seeks thermodynamic stability. The balance between enthalpy and entropy, as captured in the free energy equation, provides valuable insights into the spontaneity and direction of chemical and physical processes.