Science / Chemistry / Entropy: Entropy is a measure of energy dispersal. Any spontaneous change disperses energy and increases entropy overall. For example, when water evaporates, the internal energy of the water is dispersed with the water vapor produced, corresponding to an increase in entropy.

Standard Molar Entropy

Science / Chemistry / Standard Molar Entropy: The entropy of one mole of a substance in its standard state. MORE

Standard Entropy Of Reaction

Science / Chemistry / Standard Entropy Of Reaction: A change in entropy associated with a reaction involving substances in their standard states. A superscript circle (°) distinguishes standard enthalpy changes from enthalpy changes which involve reac MORE

Second Law Of Thermodynamics (Entropy)

Science / Biology / Second Law Of Thermodynamics (Entropy): The energy available after a chemical reaction is less than that at the beginning of a reaction; energy conversions are not 100% efficient. MORE

Third Law

Science / Chemistry / Third Law: The entropy of a perfect crystal is zero at absolute zero. MORE

Second Law

Science / Chemistry / Second Law: The second law states that every spontaneous process causes a net increase in the entropy of the universe. Many alternative statements are possible, including: Heat cannot be converted to work via an MORE

Boltzmann Equation

Science / Chemistry / Boltzmann Equation: A statistical definition of entropy, given by S = k ln W, where S and k are the entropy and Boltzmann's constant, respectively, and W is the probability of finding the system in a particular state. MORE