Entropy (S) can be best understood as *“the effect of probability on a physical or chemical processes”*. This relationship is famously described by the Boltzmann entropy formula which relates the probability of a particular state (*P _{1}*) to the chemical or mechanical work (ΔG) required to obtain that state.

Entropy changes(ΔS), are not probabilities

*per se*but rather a conceptual bridge between probability and energy. In this equation,

*k*is the Boltzmann constant,

*T*is temperature,

*P*is the probability of the considered state, ΔS is the entropy change and ΔG is the free energy change.