Exothermic vs Exergonic and Endothermic vs Endergonic

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Yang Chen 2E
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Joined: Thu Jul 13, 2017 3:00 am

Exothermic vs Exergonic and Endothermic vs Endergonic

Postby Yang Chen 2E » Sun Jan 28, 2018 11:04 pm

I'm not sure which forum to post this on so I will place this here. I'm a little confused about Exothermic vs Exergonic and Endothermic vs Endergonic. In my LS7A class, one of the questions stated that a reaction in an open system with a positive change in enthalpy is exergonic. I'm not sure as why this is possible.

Chris Pleman 3E
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Re: Exothermic vs Exergonic and Endothermic vs Endergonic

Postby Chris Pleman 3E » Sun Jan 28, 2018 11:21 pm

Exo/Endothermic represents the relative change in heat/enthalpy in a system, whereas Exer/Endergonic refers to the relative change in the free energy of a system.

Allison Young 1K
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Re: Exothermic vs Exergonic and Endothermic vs Endergonic

Postby Allison Young 1K » Sun Jan 28, 2018 11:27 pm

Exothermic means the reaction releases heat. ΔH<0
Endothermic means the reaction requires heat. ΔH>0
Exergonic means the reaction is spontaneous, and releases energy. ΔG<0
Endergonic means the reaction is non-spontaneous, so it requires energy. ΔG>0

A reaction in an open system with positive ΔH would be endothermic, as it is absorbing heat. I guess it would be exergonic if the reaction occurred on its own.

604807557
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Re: Exothermic vs Exergonic and Endothermic vs Endergonic

Postby 604807557 » Sun Jan 28, 2018 11:58 pm

Exothermic/Endothermic: refer to transfer of heat or changes in enthalpy
Exergonic/Endergonic: refer to changes in free energy

Positive enthalpy change is endergonic because heat is absorbed and the products are higher in energy than the reactants


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