∆S for summation

[Malia Shitabata 1F]

Can someone reexplain what Dr. Lavelle meant by ∆S being unnecessary when he was discussing calculating ∆Gº using standard enthalpy of formation and standard molar entropy values?
∆Sºrxn=∑Sºm(products)-∑Sºm(reactants)

[Nathan Nakaguchi 1G]

I'm not very sure, but my guess is that since its standard Gibbs free energy the only thing you need to do to calculate it is to do a Hess's approach only involving standard G's of formation.

[Norman Dis4C]

Are you sure that is what Dr. Levelle said? To my understanding, you can still calculate for G using deltaG=-Tdelta Stotal, which left out enthalpy but not entropy.

[kevinolvera1j]

∆S for the products and reactants can be ignored because the function: ∆Sºrxn=∑Sºm(products)-∑Sºm(reactants) is only dependent on the actual values of the molar entropies not changes in the molar entropies.