Enthalpy & Spontaneity

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Enthalpy & Spontaneity

Postby 805383532 » Sun Jan 26, 2020 3:20 pm

How is enthalpy related to the spontaneity of a reaction?

Juliet Stephenson 4E
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Joined: Wed Sep 18, 2019 12:21 am

Re: Enthalpy & Spontaneity

Postby Juliet Stephenson 4E » Sun Jan 26, 2020 3:43 pm

An endothermic reaction can only occur when there is excess free energy in the environment, while an exothermic reaction can occur in the absence of this energy. Therefore, the larger the deltaH value, the less spontaneously the reaction will occur.

Deepika Reddy 1A
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Joined: Thu Jul 11, 2019 12:15 am

Re: Enthalpy & Spontaneity

Postby Deepika Reddy 1A » Sun Jan 26, 2020 3:49 pm

If the reaction has a positive enthalpy, then it is endothermic and is non -spontaneous as it requires heat in order to occur. If the reaction has a negative enthalpy, then it is exothermic and is spontaneous.

Natalie Benitez 1E
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Joined: Fri Aug 02, 2019 12:15 am

Re: Enthalpy & Spontaneity

Postby Natalie Benitez 1E » Sun Jan 26, 2020 3:59 pm

What exactly is the concept of spontaneity and how does it relate to enthalpy?

Jessica Li 4F
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Joined: Fri Aug 09, 2019 12:16 am

Re: Enthalpy & Spontaneity

Postby Jessica Li 4F » Sun Jan 26, 2020 4:04 pm

If a reaction is spontaneous, it means that no additional energy is needed for the reaction to occur. It will just happen naturally (although this doesn’t indicate how fast a reaction will occur). You can determine spontaneity using Gibbs free energy or delta G — if the value is negative in a reaction, it will be spontaneous. Since delta G is determined in part by enthalpy, the enthalpy can affect is delta G is positive or negative.

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