I have checked about a dozen sources and have not grasped the physical interpretation of enthalpy. Why this term is so important? Is it only limited to a mathematical relationship, i.e. H = U + PV? Or, does it possesses any QUALITATIVE MEANINGS? Please do tell me the "meanings" and essence of enthalpy. I have been told that some people grasp it so well that they only use this property to describe a FLUID!!! Kindly tell me what it means.
Answer Beyond its mathematical statement, enthalpy gives an alternate view of the energy of a system.. When viewed in terms of change, it represents the change in the energy of a system held at a constant pressure... whereas internal energy (or a change in it) is measured with the system held to a constant volume... scientists dealing with chemical reactions find great utility in this fluid property...
