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Kaylin Krahn 1I
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Postby Kaylin Krahn 1I » Mon Feb 05, 2018 9:21 pm

Why is it that the compounds with a positive free energy of formation are unstable with respect to the elements?

Kelly Kiremidjian 1C
Posts: 62
Joined: Fri Sep 29, 2017 7:04 am

Re: 9.63

Postby Kelly Kiremidjian 1C » Mon Feb 05, 2018 9:49 pm

Thermodynamic stability occurs when a system is in its lowest energy state. Therefore, compounds with positive free energy are said to be unstable while compounds with negative free energy are said to be stable.

Sally Nason - 1K
Posts: 40
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Re: 9.63

Postby Sally Nason - 1K » Mon Feb 05, 2018 9:52 pm

If the value for delta G is negative then energy needs to be added in order to form the compound so therefore it would not be stable, as it doesn't occur spontaneously. However, a negative delta G for a compound means the compound can form without any stimulus or added energy and is therefore a stable compound.

Janine Chan 2K
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Joined: Fri Sep 29, 2017 7:04 am

Re: 9.63

Postby Janine Chan 2K » Wed Feb 07, 2018 7:13 pm

In order for decomposition of compounds into their elements to be stable, ∆G of decomposition would have to be (+) aka it won't spontaneously break down. Since decomposition is the opposite of formation, ∆Gf would have to be (-). In other words, the formation is spontaneous and the decomposition is not spontaneous (and thus stable).

Kevin Tabibian 1A
Posts: 42
Joined: Fri Sep 29, 2017 7:06 am

Re: 9.63

Postby Kevin Tabibian 1A » Wed Feb 07, 2018 7:29 pm

A negative change in Gibbs free energy means that the product will be spontaneously favoured and therefore more stable

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