At the molecular level, the value of the entropy of the distribution of atoms and molecules in a thermodynamic system is a measure of the disorder in the arrangements of its particles. In thermodynamics, a parameter representing the state of disorder of a system at the atomic, ionic, or molecular level the greater the disorder the higher the entropy. Įntropy is a measure of the unavailability of a system’s energy to do work. Similarly, the absolute entropy of a substance tends to increase with increasing molecular complexity because the number of available microstates increases with molecular complexity. Soft crystalline substances and those with larger atoms tend to have higher entropies because of increased molecular motion and disorder. In contrast, graphite, the softer, less rigid allotrope of carbon, has a higher entropy due to more disorder in the crystal. We will consider each of these factors in turn.Īmong crystalline materials, those with the lowest entropies tend to be rigid crystals composed of small atoms linked by strong, highly directional bonds, such as diamond. (2) The mass of the atoms and molecules which are moving-the greater the mass, the larger the entropy. There are two aspects of the molecular structure of a substance that affect the value of its entropy: (1) The degree to which the movement of the atoms and molecules in the structure is restricted-the less restricted this movement, the greater the entropy.

Absolute specific entropy