### Delta G

Posted:

**Thu Feb 14, 2019 5:03 pm**How can you tell if increasing temperature will increase or decrease the stability of a molecule?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=135&t=42235

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Posted: **Thu Feb 14, 2019 5:03 pm**

How can you tell if increasing temperature will increase or decrease the stability of a molecule?

Posted: **Thu Feb 14, 2019 5:27 pm**

The Gibbs free energy equation is (delta G) = (delta H) - (temperature)(delta S).

When (delta S) is positive and (delta H) is positive, then the reaction will be spontaneous at high temperature.

When (delta S) is positive and (delta H) is negative OR when (delta S) is negative and (delta H) is positive, the temperature will not affect spontaneity.

When (delta S) is negative and (delta H) is negative, then the reaction will be spontaneous at low temperature.

Hope this helps!

When (delta S) is positive and (delta H) is positive, then the reaction will be spontaneous at high temperature.

When (delta S) is positive and (delta H) is negative OR when (delta S) is negative and (delta H) is positive, the temperature will not affect spontaneity.

When (delta S) is negative and (delta H) is negative, then the reaction will be spontaneous at low temperature.

Hope this helps!

Posted: **Fri Feb 15, 2019 10:04 am**

The formula for Gibbs free energy is deltaG = deltaH - TdeltaS

If deltaG is negative, the reaction is spontaneous. If it is positive, the reaction is not spontaneous.

Thus, the higher the temperature, the lower the Gibbs free energy, making it more spontaneous, and thus less stable.

If deltaG is negative, the reaction is spontaneous. If it is positive, the reaction is not spontaneous.

Thus, the higher the temperature, the lower the Gibbs free energy, making it more spontaneous, and thus less stable.