### Spontaneity

Posted:

**Wed Feb 27, 2019 6:21 pm**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!

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=135&t=43254

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Posted: **Wed Feb 27, 2019 6:21 pm**

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!

Posted: **Wed Feb 27, 2019 6:43 pm**

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).

Posted: **Wed Feb 27, 2019 7:13 pm**

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

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

Posted: **Wed Feb 27, 2019 7:19 pm**

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