Spontaneity

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Helen Struble 2F
Posts: 97
Joined: Sat Aug 24, 2019 12:17 am

Spontaneity

Postby Helen Struble 2F » Sun Mar 01, 2020 8:20 pm

I'm still having difficulty understanding what it means if a reaction is spontaneous. How could a reaction be spontaneous but also never proceed in the forward direction (diamonds to graphite example)?

Fiona Latifi 1A
Posts: 102
Joined: Sat Sep 14, 2019 12:16 am

Re: Spontaneity

Postby Fiona Latifi 1A » Sun Mar 01, 2020 8:27 pm

The reaction of diamonds to graphite does occur, and it is spontaneous. It just occurs at an EXTREMELY slow rate.

205007651
Posts: 53
Joined: Tue Nov 13, 2018 12:17 am

Re: Spontaneity

Postby 205007651 » Sun Mar 01, 2020 8:28 pm

This is due to kinetic stability. For diamond to become graphite, there is a large activation energy barrier that needs a lot of energy to overcome and ultimately prevents the conversion to graphite in a forward direction

Anna Heckler 2C
Posts: 102
Joined: Wed Sep 18, 2019 12:18 am

Re: Spontaneity

Postby Anna Heckler 2C » Sun Mar 01, 2020 8:32 pm

While a reaction is spontaneous, its activation energy could be so large that it occurs at an incredibly slow rate.

Frank He 4G
Posts: 50
Joined: Tue Nov 12, 2019 12:19 am

Re: Spontaneity

Postby Frank He 4G » Sun Mar 01, 2020 8:49 pm

Another way to imagine this is that a reaction such as that actually has two steps. One where the bonds of the reactants are broken, and one where the bonds of the products are formed. To break bonds, you need to put in energy.


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