entropy of vaporazation

Entropy:
Entopy measurements if they could be made would apparently give us some information about the structure of molecules of solid and liquids but how can this be done what are the entropy unit s mentioned in the , calssical thermodynamics provides the answer in fact historically this approach came before that of statistical thermodynamics the existence of an entropy function was postulated by the thermodynamicists before its behaviour and singnificance were expanded by this statistical mathematicians,in which the system is changed from a to b and back again even though by two different routes we know from the first law of thermodynamic and the nature of thermodynamic variables that the change in intrernal energy will be zero and that values of preasure and volume will not change as a result of asystem being taken through such a cycle.therfore the work done by the system w must be the same as the heat absorbed by the system in traving such a cycle if we have some sort of machine or heat engine which can convert heat into mechanical work we can define the efficiency of the machine which can be converted into work,