Welcome Guest Search | Active Topics |

Tag as favorite
Enthalpy
Options
Previous Topic Next Topic
Dejan_3900
#1 Posted : Wednesday, July 08, 2020 10:24:08 PM
Rank: Newbie

Groups: Registered
Joined: 5/20/2019
Posts: 7

Thanks: 0 times
Was thanked: 0 time(s) in 0 post(s)
In what situation would we see enthalpy being positive and the overall process being exothermic?
Back to top
Report?
INSTR_Molly_59
#2 Posted : Saturday, July 11, 2020 5:53:41 PM
Rank: Member

Groups:
Joined: 7/12/2019
Posts: 28

Thanks: 0 times
Was thanked: 0 time(s) in 0 post(s)
Are you talking about Gibbs free energy, and a reaction being exergonic (spontaneous)?

In no case, would a reaction ever be exothermic (heat releasing) and have a positive enthalpy (dH). Exothermic itself dictates a negative dH (d = delta, the triangle symbol).

Exergonic however, refers to the calculation of Gibbs free energy, which incorporates the temperature, and entropy, as well, to calculate the absorbance or release of energy of the system.

Gibbs free energy equation states: dG = dH - TdS

So if you are looking for a reaction that is exergonic, you are looking for a negative dG. To have a negative dG with a positive enthalpy, your TdS MUST be even more negative. So therefore, you require -TdS > dH for your reaction to be exergonic.

Hope this helps! If you need more assistance, please reply below.

Cheers, and happy studying! :)
Back to top
Report?
Users browsing this topic
Guest
Tag as favorite
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.

Clean Slate theme by Jaben Cargman (Tiny Gecko)
Powered by YAF | YAF © 2003-2009, Yet Another Forum.NET
This page was generated in 0.073 seconds.