(vii) Entropy, S is related to thermodynamic probability (W) by the relation,Įntropy changes in system & surroundings and total entropy change for Exothermic and Endothermic reactions Heat increases the thermal motion of the atoms or molecules and increases their disorder and hence their entropy. Unavailable energy = Entropy × Temperature (vi) Entropy is a measure of unavailable energy for useful work. The sum is called entropy change of universe. (v) The total entropy change of an isolated system is equal to the entropy change of system and entropy change of the surroundings. (iv) The change in entropy for a cyclic process is always zero. (iii) The change in entropy in going from one state to another is independent of the path. (ii) Entropy of a system is a state function. Its value depends upon the amount of the substance present in the system. The important characteristics of entropy are summed up below In SI units, the entropy is expressed in terms of joule per degree Kelvin, i.e. Since entropy change is expressed by a heat term divided by temperature, it is expressed in terms of calorie per degree, i.e.,cal deg-1. The entropy change of a system may be defined as the integral of all the terms involving heat exchanged (q) divided by the absolute temperature (T) during each infinitesimally small change of the process carried out reversibly at constant temperature. It is more convenient to define the change of entropy during a change of state. It is difficult to define the actual entropy of a system. Entropy is represented by the symbol “S”. Entropy is a thermodynamic state quantity which is a measure of randomness or disorder of the molecules of the system.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |