Gibbs free energy

[chiral]

Can someone please explain the difference between delta G knot and delta G?

and also what is the significance of this equation: S= q/T and when do we use this

thanks

[cohen]

Delta G knot is at standard conditions, and delta g is at any conditons (I believe this is correct =P, i know it definately is for delta g knot).

For S = q/t, it's significance can be used to find the temperature of the system when we are given a specified entropy and enthalpy (E.g. if the systems at equilibrium)
delta(g) = delta(h)-T*delta(s) = 0, so rearranging this we can get T = Delta(h)/Delta(s). I think there was like two questions in the tutes last week that explained that

[chiral]

thanks cohen I get gibbs free energy now but i think S=q/T still isn't as clear. I'll look at the tute exercises you are referring to