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Gibbs free energy and spontaneity

Posted: Sun Feb 11, 2018 3:04 pm
by Liam Maxwell 2E
Is calculating G the only way to officially conclude spontaneity? Because based on the equation calculating merely entropy or enthalpy doesn't appear to be enough.

Re: Gibbs free energy and spontaneity

Posted: Sun Feb 11, 2018 3:07 pm
by Aijun Zhang 1D
Yeah, basically you need delta G to determine spontaneity.
Or you can use K to indirectly find the spontaneity at equilibrium.

Re: Gibbs free energy and spontaneity

Posted: Sun Feb 11, 2018 3:08 pm
by Kyle Sheu 1C
A spontaneous process is one that increases the entropy of the universe, which we can calculate by taking the sum deltaSsys + deltaSsurr.

So deltaG is not the ONLY way to determine thermodynamic favorability, but as it is often difficult to measure the change in entropies of system and surroundings, we make use of the changes in enthalpy and entropy of the system to calculate deltaG as an applicable method of determining spontaneity.

Re: Gibbs free energy and spontaneity

Posted: Sun Feb 11, 2018 3:14 pm
by Caroline LaPlaca
Yes because entropy and enthalpy both affect the chance of spontaneity.