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Negative ∆G means spontaneous reaction?

Posted: Thu Feb 21, 2019 11:58 am
by Hai-Lin Yeh 1J
Why does a negative ∆G correlate with a spontaneous reaction? I thought that ∆G was the change in gibbs free energy so why is the reaction spontaneous when the change is negative?

Re: Negative ∆G means spontaneous reaction?

Posted: Thu Feb 21, 2019 12:03 pm
by Tuong-Minh Tran 1C
A spontaneous reaction occurs when a system releases energy and moves into a lower energy state. ∆G is the change in Gibbs free energy; the reason why it is negative in a spontaneous reaction is because it means that the system is releasing energy into its surroundings and thus loses free energy.

Re: Negative ∆G means spontaneous reaction?

Posted: Thu Feb 21, 2019 12:05 pm
by Manya Bali 4E
When the change in Gibbs Free Energy is negative, that means that the substance has lost energy or gone from a higher energy state to a lower and presumably more stable energy state. It makes sense that this process would be spontaneous as the substance would be releasing energy.

If the change in Gibbs Free Energy was positive, that would mean the the substance gained energy through some outside forces acting on it, so it wouldn't be spontaneous.

Re: Negative ∆G means spontaneous reaction?

Posted: Thu Feb 21, 2019 12:11 pm
by A De Castro 14B 2H
A reaction is spontaneous if it occurs without help or work. A reaction with negative ∆G° is spontaneous, since ∆G°usually results from negative ∆H° and positive ∆S°. The latter means that disorder of the universe increases, which always applies to spontaneous processes. However, remember that all of this depends on temperature. Hope this helps.

Re: Negative ∆G means spontaneous reaction?

Posted: Thu Feb 21, 2019 3:58 pm
by Tameen Ahmed 4C
Negative ∆G corresponds to a spontaneous reaction because reactants, or initial state, have more free energy than the products, or final state.

Re: Negative ∆G means spontaneous reaction?

Posted: Thu Feb 21, 2019 8:45 pm
by George Ghaly 2L
Yes a negative value resulting from the Gibbs free energy equation means that the reactants will make products spontaneously.