Thermodynamics and Interactions

(H) Enthalpy: as the sum of the system's internal energy and the product of its pressure and volume

(U) Internal energy: is defined as the energy associated with the random, disordered motion of molecules

(S)Entropy:  is a scientific concept, as well as a measurable physical property that is most commonly associated with a state of disorder, randomness, or uncertainty.

Because work is obtained from ordered molecular motion, the amount of entropy is also a measure of the molecular disorder, or randomness, of a system.

Gibbs free energy : (or Gibbs energy) is a thermodynamic potential that can be used to calculate the maximum reversible work  that may be performed by a thermodynamic system at a constant temperature and pressure measured in joules.

Boltzmann probability: The Boltzmann distribution represents a thermally equilibrated most probable distribution over all energy levels. There is always a higher population in a state of lower energy than in one of higher energy.

Heat Capacity(specific heat):Heat capacity is the ratio of the amount of heat energy transferred to an object to the resulting increase in its temperature. ... Specific heat capacity is a measure of the amount of heat necessary to raise the temperature of one gram of a pure substance by one degree K

Differential Scanning Calorimetry: (DSC) is an experimental technique to measure directly the heat energy uptake that takes place in a sample during controlled increase (or decrease) in temperature.

isothermal titration calorimetry (ITC): technique to measure The thermodynamics of interaction between molecules in solution Typically this method might be used to measure the heat of binding of a drug or inhibitor molecule to an enzyme

Differential Scanning Calorimetry(DSC)

In general, the differences in heat energy uptake between the sample and reference cells required to maintain equal temperature correspond to differences in apparent heat capacity. It is these differences in heat capacity that give direct information about the energetics of thermally induced processes in the sample