### sign of entropy

Posted:

**Mon Jan 29, 2018 4:26 pm**How do I know whether the entropy has a "+" or a "-"?

Created by Dr. Laurence Lavelle

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

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=133&t=26563

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Posted: **Mon Jan 29, 2018 4:26 pm**

How do I know whether the entropy has a "+" or a "-"?

Posted: **Mon Jan 29, 2018 4:29 pm**

As Dr. Lavelle explained today in lecture, the sign of entropy depends on the direction of heat flow. If the system loses heat, the entropy will have a negative sign in front of it. If the surroundings gain heat, the entropy will have a positive sign. I hope this helps!

Posted: **Mon Jan 29, 2018 6:00 pm**

Additionally, entropy is positive when the reaction spontaneous. It means that the system has more possible states. Entropy is negative when the system has less possible states.

Posted: **Mon Jan 29, 2018 7:45 pm**

Also, if delta entropy equals zero then the reaction is at equilibrium.

Posted: **Wed Jan 31, 2018 4:26 am**

You determine the sign of entropy by the direction of heat flow.

Posted: **Wed Jan 31, 2018 8:43 am**

Direction of heat flow determines the sign as well as whether or not the reaction is spontaneous.

Posted: **Wed Jan 31, 2018 10:25 am**

The sign of entropy indicates the direction of heat flow.

Posted: **Wed Jan 31, 2018 3:59 pm**

The sign of entropy is indicative of the heat flow in or out of the system. A system in which heat flows out to the surroundings will have a negative entropy whereas a system in which heat flows in from the surroundings will have a positive entropy.

Posted: **Wed Jan 31, 2018 10:21 pm**

sign of entropy depends on flow of heat

Posted: **Thu Feb 01, 2018 2:06 pm**

Additionally, during a process of expansion entropy increases as there are more possible states.

Posted: **Thu Feb 01, 2018 2:12 pm**

Jack Papciak 2F wrote:How do I know whether the entropy has a "+" or a "-"?

It depends on the the ratio of final to initial temperature, volume, and/or pressure. You can logically think about by analyzing whether the number of microstates is increasing or decreasing, which can give an indication to what the sign should be.

Posted: **Sun Feb 04, 2018 9:29 am**

Additionally, in connection with Gibbs free energy, if the sign of the delta G is negative, the reaction is spontaneous and favorable.