Submitted by Elliott on Tue, 01/21/2014 - 03:42 ‹ 02.07 The Closed-System Energy Balance up 02.09 The Complete Energy Balance › Printer-friendly version Comments Elliott replied on Tue, 01/21/2014 - 04:00 Permalink Understanding Enthalpy Understanding Enthalpy (uakron.edu, 6min) The vocabulary just keeps on coming. Usually, it helps to picture the physical process and think about what is happening with the molecules. Then the names applied nearly always make sense as they refer to some specific part of the overall picture. This is not the case for enthalpy. Enthalpy is merely a convenient lumping of other more fundamental terms. It has purely a mathematical definition. There is nothing physical about it. Keep in mind that this kind of arbitrary definition is the exception, not the rule. The rule is: try to understand each aspect of vocabulary in terms of its physical meaning. An exception is enthalpy. Enthalpy has no physical meaning.