Endergonic/Exergonic versus Exothermic/Endothermic

[pandalove89]

I understand the concepts when comparing exothermic and endothermic reactions, but where does endergonic and exergonic reactions come into play?

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[AlbinoPolarBear]

I understand the concepts when comparing exothermic and endothermic reactions, but where does endergonic and exergonic reactions come into play?

For delta H, exothermic and endotherm tells us about the relative stabilities of each reactant/products. It does not tell us if the reaction will take place or not (we need to know activation barrier)\

For delta G, exergonic and endergonic will tell us if the reaction will take place or not (spontaneous vs non-spontaneous).

The formula: dG = dH - TdS .

Reactions will be spontaneous (exergonic) if dG < 0. If you look at the equation, raising the temperature of the reaction will decrease dG.

Reactions will be non-spontaneous (endergonic) if dG > 0. If you look at the equation, raising the temperature will increase dG.

So some reactions that are non-spontaneous (dG>0) may become spontaneous if the temperature is raised high enough.

Hope that helps!

 

[toothlove]

For me, I needed to know that if something was put into a solution and the temperature decreased, it meant the reaction was endo. This was because heat was being taken into it. The opposite is true for exo. Hope this helps!