calculate absolute entropy from standard entropy

This is the basis of an alternative (and more fundamental) definition of entropy: With more available microstates, the entropy of a system increases.

In contrast to the macrostate, which characterizes plainly observable average quantities (temperature, for example), a microstate specifies all molecular details about the system, including the position and velocity of every molecule. For a given set of macroscopic variables, the entropy measures the degree to which the probability of the system is spread out over different possible microstates. The interpretation of entropy is the measure of uncertainty, which remains about a system after its observable macroscopic properties, such as temperature, pressure, and volume, have been taken into account. Thermodynamic entropy has the dimension of energy divided by temperature, which has a unit of joules per kelvin (J/K) in the International System of Units. As a result, entropy (denoted by S) is an expression of disorder or randomness. These processes reduce the state of order of the initial systems. It determines that thermal energy always flows spontaneously from regions of higher temperature to regions of lower temperature, in the form of heat. Therefore, entropy is also a measure of the tendency of a process, such as a chemical reaction, to be entropically favored or to proceed in a particular direction. In classical thermodynamics, the second law of thermodynamics states that the entropy of an isolated system always increases or remains constant. microstate: The specific detailed microscopic configuration of a system.Įntropy of the Playroom: Andrew Vanden Heuvel explores the concept of entropy while cleaning the playroom.entropy: A thermodynamic property that is the measure of a system’s thermal energy per unit temperature that is unavailable for doing useful work.Fundamentally, the number of microstates is a measure of the potential disorder of the system.The more such states available to the system with appreciable probability, the greater the entropy.The entropy of an isolated system always increases or remains constant.Incorporation of iodine into apatite structure: a crystal chemistry approach using Artificial Neural Network. Contributions to Mineralogy and Petrology, 177(11), 1-34. The prediction method for standard enthalpies of apatites using the molar volume, lattice energy, and linear correlations from existing experimental data. Standard absolute entropy, values from volume or density. by the Polish National Science Centre (NCN) grant No. Financial support for the research was provided to B.P. Selected estimated standard entropies (S°) and calculated formation entropies (ΔS°f, el)of iodine apatites. Errors bars are within the marker.Table 1. formula unit volume (Vm)for selected apatite subgroups. A system of linear relationships (calibrated with existing experimental data) indicating high positive correlations within selected subgroups of apatites is presented in Fig. We found strong linear relationships between S° of apatites and their Vm observed within these subgroups. These subgroups are formed by Me10(AO4)6X2 with the same Me2+ cations (e.g., Pb2+, Cd2+, Ca2+, Ba2+, Sr2+) and tetrahedral AO43- anions (e.g., A=P, As, V), but with different anions at the X position (e.g., F-, Cl-, Br-, I-, OH-). In the early 2000's Jenkins and Glasser showed that the formula unit volume alone, Vm, can be used to estimate the standard entropy for any inorganic compound.It was recently indicated that in terms of their thermodynamic properties, the apatite supergroup splits into distinct subgroups (populations). Consequently, they are an incomparable testing ground for finding regularities in the variation of their thermodynamic function of state, e.g., standard entropy (S°). The Apatite supergroup is one of the largest groups of minerals. The standard absolute entropies of many minerals and mineral-based inorganic materials are unknown, thereby precluding a complete insight into their thermodynamic stability.

Calculate absolute entropy from standard entropy