(a) If, for the reaction in Equation (1),
NH4+(g) + Cl-(g) NH4Cl(aq)
we find that delta H= -159.3 kcal mol-1, find
delta H for the reaction in Equation (2):
NH4Cl(s) NH4+(g) + Cl-(g).
The reactions given by Equations (1) and (2) are of
sufficient importance that special names are attached to this type
of reaction. The reaction of Equation (1) gives a hydration
enthalpy, which is a measure of forces of attraction between
dipolar water molecules and ions.
(b) If the hydration enthalpy of...