Table 1.

Calculation of the polar interaction between water and acetamide

	ΔG, kcal/mol	ΔH, kcal/mol
Observed*	−9.70	−16.87
vdw + cavity†	1.95	−5.22
Polar‡	−11.65	−11.65

^*ΔG from Wolfenden and coworkers (28, 29) at 25°C, and ΔH from (30). 

^†The sum of the contributions from van der Waals interactions and cavity formation by a nonpolar compound with the same ASA, found from vapor-water transfer data for nonpolar compounds. The polar and nonpolar surface areas of acetamide are 95 and 97 (Ų), respectively. 

^‡The polar hydration energies found by subtracting ΔG_vdw+cav from ΔG_obs and similarly for ΔH.