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spontaneous reactions

Posted: Sun Feb 23, 2020 10:44 pm
by Jasleen Kahlon
What exactly does a reaction being spontaneous mean in terms of thermodynamics, and what occurs when ∆S and ∆H are either both negative or both positive?

Re: spontaneous reactions

Posted: Sun Feb 23, 2020 10:47 pm
by Ashley Wang 4G
A spontaneous reaction means it will tend to occur under the given conditions without an outside source of energy. Note that it says nothing about the speed of the reaction!

When ∆S and ∆H are either both negative or both positive, that is when the temperature dependence of the reaction becomes very important, as the magnitude of T will determine whether the reaction will be spontaneous.

Hope this helps!

Re: spontaneous reactions

Posted: Sun Feb 23, 2020 10:50 pm
by saigorijavolu2k
A negative delta S means that the reverse reaction is spontaneous. A positive delta S means that the forward reaction is spontaneous. A negative delta H means that it is exothermic and usually exothermic reactions are associated with being spontaneous because they release energy.