Question

Define endropy what are its unit​

Answer 1

★ Entropy

• Entropy, one of the parameters that characterize the state of matter in thermodynamics, is represented by the symbol (S), and its physical meaning is a measure of the degree of chaos in the system.

Entropy has units → joules per kelvin (J/k) or kg m² s ^-2 / k

★ Application

Entropy was originally a material state parameter reflecting the irreversibility of the spontaneous process according to the second law of thermodynamics. The second law of thermodynamics is a law summed up from a large number of observations: in an isolated system, there is no energy exchange between the system and the environment, the system always changes spontaneously toward the direction of increasing chaos, always increasing the entropy value of the entire system This is the principle of entropy increase . Friction causes some mechanical energy to irreversibly transform into heat, increasing entropy, so the entire universe can be regarded as an isolated system, which is evolving in the direction of increasing entropy.

From a spontaneous process to investigate: the heat Q is transferred from the high temperature (T1) object to the low temperature (T2) object, the entropy of the high temperature object decreases dS1 = dQ / T1 , and the entropy of the low temperature object increases dS2 = dQ / T2 , the two objects together as a system point of view, is the entropy change dS = dS2 -dS 1 > 0.