Physical meaning of entropy and Enthalpy

Entropy is a measure of molecular dis - oderness or randomness, greater is the disorderness lesser the efficiency.                    " Entropy change of univers "

  ds >or = dQ/ T

  ds (universe) > or = 0 

( universe is a isolated system)

ds ( system) + ds ( surrounding) > or = 0

Entropy of the system can increase or decrease or it can remain constant. Similarly the entropy of surrounding can increase or decrease or it can remain constant but " the overall change in Entropy of univers can never decrease.

Q. What is source and sink?

Ans-: source-: source is a reservoir, which supplies thermal energy without undergoing any temperature change .

Sink -: It is a reservoir which absorb thermal energy without undergoing any temperature change. 

Enthalpy -: In thermodynamics the term " u + Pv " is taken as Enthalpy. 

H = u + Pv

It is an extensive property and generally express in " KJ".

Specific Enthalpy  H/m = h = KJ/Kg