Spontaneity [ENDORSED]

$\Delta G^{\circ}= \Delta H^{\circ} - T \Delta S^{\circ}$

$\Delta G^{\circ}= -RT\ln K$

$\Delta G^{\circ}= \sum \Delta G_{f}^{\circ}(products) - \sum \Delta G_{f}^{\circ}(reactants)$

melissa_dis4K
Posts: 106
Joined: Fri Sep 28, 2018 12:28 am

Spontaneity

How can I determine whether a reaction is spontaneous or not from given delta S of the system and delta S of the surroundings? Thanks!

Patrick Cai 1L
Posts: 93
Joined: Fri Sep 28, 2018 12:25 am

Re: Spontaneity

Typically, if only considering entropy of a reaction, if delta S is positive, then the reaction is considered spontaneous. However, there are more cases where temperature and enthalpy would need to be considered (Gibbs free energy equation).

melissa_dis4K
Posts: 106
Joined: Fri Sep 28, 2018 12:28 am

Re: Spontaneity

This is regarding Karen's Gibbs Free energy worksheet question 2. It says:
Use the following values for entropy, determine if a reaction would be spontaneous for each case.
a. delta S system= 30J/K ; delta S surroundings= 50 J/K
Thanks

melissa_dis4K
Posts: 106
Joined: Fri Sep 28, 2018 12:28 am

Re: Spontaneity  [ENDORSED]

Nvm! Delta S of universe = delta S (system) + delta S (surr) and if this is greater than 0 then it is spontaneous!

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