The purpose of this study has been to determine the effect of substituting DeltaQdegrees for Tdegrees DeltaSdegrees in the Gibbs free energy equation (DeltaGdegrees = DeltaHdegrees -TdegreesDeltaSdegrees, Eq. (1)) so that DeltaG(DeltaQ)degrees = DeltaHdegrees - DeltaQdegrees (Eq. (2)). The result is that values of Delta(c)G(DeltaQ)degrees averaged 1.04 +/- 0.01 (n = 5) times more negative than those of A,G' for the bomb calorimetric oxidations of five liquid catabolic substrates, with a range 1.02-1.06. Values of Delta(c)G(DeltaQ)degrees averaged 1.03 +/- 0.01 (n = 17) times more negative than those of Delta(c)Gdegrees for 17 theoretical bomb calorimetric oxidations of solid catabolic substrates, with a range 1.02-1.05. While significant, these differences are not large because in bomb calorimetric oxidations the values of Tdegrees Delta(c)Sdegrees and Delta(c)Qdegrees are small compared to those of Delta(c)Hdegrees. On the other hand, for six fermentations values of Tdegrees Delta(p)Sdegrees and Delta(p)Qdegrees are much larger compared to values of Delta(p)Hdegrees than those for oxidations. Here, values of Delta(p)Gdegrees showed wide variations from Delta(p)G(DeltaQ)degrees, ranging from 4.88 times greater to 0.88 times less. Clearly, the whole approach to making these calculations using Eq. (2) is fundamentally different and significant to the extent given above. The difference between the use of Eqs. (1) and (2) is not trivial. Eq. (2) represents a different interpretation of the method of calculating the change in the quantity of absorbed thermal energy exchanged by an irreversible system such as a growth process as it passes from an initial to a final state. It is certainly more simple. It may be more correct. Because DeltaG(DeltaQ)degrees is not the same as DeltaGdegrees, it is suggested that the DeltaG(DeltaQ)degrees term in Eq. (2) be changed to DeltaXdegrees, this letter not being previously used in biological thermochemistry, so that DeltaXdegrees = DeltaHdegrees - DeltaQdegrees.