What does the term "thermodynamic equilibrium constant" refer to?

The term "thermodynamic equilibrium constant" specifically refers to the equilibrium constant denoted by K. At a given temperature, K describes the ratio of the concentrations of the products to the concentrations of the reactants for a reversible chemical reaction at equilibrium. This constant is derived from the Gibbs free energy change (∆G) and reflects the extent to which a reaction favors products over reactants under equilibrium conditions.

K is crucial in predicting the direction of a reaction and determining how it will shift when subjected to changes like temperature, pressure, or concentration according to Le Chatelier's principle.

The other terms mentioned do not describe the equilibrium constant. Q is the reaction quotient, which is similar to K but is used to determine the direction of the reaction before it reaches equilibrium. ∆H refers to the change in enthalpy, which is related to heat and energy changes but does not define the equilibrium state of a reaction. ∆U represents the change in internal energy of a system and is also unrelated to the equilibrium constant.