Concepts

$\Delta G^{\circ}= \Delta H^{\circ} - T \Delta S^{\circ}$

$\Delta G^{\circ}= -RT\ln K$

$\Delta G^{\circ}= \sum \Delta G_{f}^{\circ}(products) - \sum \Delta G_{f}^{\circ}(reactants)$

CaminaB_1D
Posts: 63
Joined: Fri Sep 28, 2018 12:16 am

Concepts

I do not completely understand how the values of enthalpy and entropy explain the spontaneity of a reaction (aka the concepts of the Gibbs free energy equation), can someone give me a quick run down?

Elias Omar 1G
Posts: 52
Joined: Fri Sep 28, 2018 12:17 am

Re: Concepts

Gibbs Free Energy is what really determines spontaneity:
If ∆G is negative then the reaction is spontaneous. If it's positive the reaction is non-spontaneous.
Here's how to relate entropy and enthalpy to spontaneity:
∆G positive, ∆ H negative - Spontaneous at all temperatures
∆G positive, ∆H positive - Spontaneous at high temperatures
∆G negative, ∆ H negative - Spontaneous at low temperatures
∆G negative, ∆ H positive - Process not spontaneous at any temperature, however reverse process is spontaneous at all temperatures

Nandhini_2K
Posts: 60
Joined: Fri Apr 06, 2018 11:03 am

Re: Concepts

If delta G is negative: favors products and spontaneous in forward rxn.
If delta G is positive: favors reactants and non-spontaneous in forward rxn.
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