entropy (S): meaning?

[jackie jackson <jackie_jacky %! at !% yahoo.com>]

Dear cclers,
 In the frequency calculation of G98, it gives thermal enthalpies (H),
 thermal free energies(G) and entropies (S) as well. For reaction
 A+B-->C the enthalpy change of the reaction dH=H(c)-H(A)-H(B)=dH° at
 T=298K. If dG=dH+T(dS)=dG° we can calculate rate constant for the
 reaction. My question is:
 1. Does (delta)S=(delta)S° ? Why?
 2. What is the physical meaning of S given in g98    frequency
 calculation?
 3. Does the calculation of S include the all motion    states of a
 molecule ? What is included and what is    not?
 4. Is there a way to calculate dG° using g98 ?
 I would appreciate your time and replies. And I'll
 summarize.
 Thank you very much.
 Jackie
 Kinetics, Inc.
 Lowell, MA
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