What is entropy?

Entropy is a disorder. Anything that contributes to the creation of disorder generates entropy. In many cases, you would find a close relation between thermodynamics and human behavior. A person in a situation where he feels completely relaxed, totally composed, and sure of himself or in control of himself always has more capability to work in any form. He is more motivated to do work. Molecules behave exactly like this. A relaxed molecule relatively can focus more on work than when there is too much chaos that distracts the molecule from doing work. It loses focus on work and engages itself to cope with chaos/disorder. The same applies to entropy. Entropy is always increasing in the universe in everything. Because everything in nature wants to go to a stable state of equilibrium from high energy to low energy by dissipating its energy by creating disorder. This disorder is entropy.

Definitions of entropy

-Entropy is a disorder of molecules -Entropy is a loss of energy when heat converts to work

-Entropy is energy loss in Joule/mole-K expressed as ?S = Q/T -Entropy is the spread of energy

-Entropy measures how far a system is from equilibrium

-Entropy changes at equilibrium is zero. ?H = T?S, no enthalpy available to do work at equilibrium. At equilibrium, ?S = Q rev/T.

How does entropy change?

Some examples

-Entropy changes when the heat does work by compression/expansion.

-Entropy changes when a process is irreversible' Any heat that goes to surroundings cannot be brought back. All such systems are called irreversible systems. When the sum of entropy generation is a system and surroundings is > 1, the system is called irreversible. S 1 [system] = Q/T1, S 2 [surroundings] = Q/T2, Q is the heat. T1 is the system temperature. T2 is the temperature of the surroundings. When S1 = S2 there is no generation of entropy. The system is an equilibrium When S2 > S1 or in other words T2 < T1, There is a generation of entropy. S (generation) = S2 - S1

-Entropy changes with an increase in the concentration of molecules

-Entropy reduces with an increase in pressure. Increased pressure brings the molecules closer and reduces disorder.

-Entropy increases with the increasing number of molecules or more spread of molecules. More spread of molecules means more disorder.

?-Entropy increases with the size of a molecule

-Entropy increases with an increase in volume

-Entropy changes with specific heat. For a change in temperature T k the entropy changes by Q/T, if Q is the heat. The same Q/T is the specific heat of the substance if the mass is constant. The higher the specific heat capacity, the smaller the temperature change and the colder the substance for the same amount of heat applied to the same mass of substance, therefore, the smaller the entropy increase.