## Different Types of Entropies

Jason Wu 1E
Posts: 101
Joined: Thu Jul 25, 2019 12:15 am

### Different Types of Entropies

Through practice problems, I have come across various types of Entropies including S, Delta S, Delta S total, and Delta S surroundings. What do each one of them mean and how do they relate to each other? Thanks!

Megan Cao 1I
Posts: 103
Joined: Sat Sep 07, 2019 12:18 am

### Re: Different Types of Entropies

S is just entropy itself
delta S is the change in entropy
delta S total is the total change in entropy within a universe ( Ssys + Ssurr)
delta S surroundings is the change in entropy within the surroundings

Hope this helps in some way!

Emma Popescu 1L
Posts: 105
Joined: Wed Sep 11, 2019 12:16 am

### Re: Different Types of Entropies

Also when the reaction is reversible delta S total=0 so delta S system= - delta S surroundings

Helen Struble 2F
Posts: 97
Joined: Sat Aug 24, 2019 12:17 am

### Re: Different Types of Entropies

Delta S and its variants (system, surroundings, total) represent a state function (change in entropy). We can find the value of this change through the equations given to us. However, because a delta valley represents a final value minus and initial value, we know that any system must have a set value for entropy at any given time, even if there is no change in the system. This is calculated using the Boltzmann equation.

Amy Kumar 1I
Posts: 114
Joined: Thu Jul 11, 2019 12:15 am

### Re: Different Types of Entropies

The entropy of the system and surroundings added up equal the entropy of the surroundings. In cases where the entropy of the surroundings is 0, the entropy of the system equals -1*entropy of the surroundings.

RichBollini4G
Posts: 100
Joined: Wed Sep 18, 2019 12:18 am

### Re: Different Types of Entropies

Megan Cao 1I wrote:S is just entropy itself
delta S is the change in entropy
delta S total is the total change in entropy within a universe ( Ssys + Ssurr)
delta S surroundings is the change in entropy within the surroundings

Hope this helps in some way!

thank you this was very helpful

Miriam Villarreal 1J
Posts: 105
Joined: Sat Aug 17, 2019 12:16 am

### Re: Different Types of Entropies

The entropy of the surroundings will increase if energy (heat) is flowing into the surroundings from the system.If we are given the entropy changes of the system and surroundings, we can calculate total entropy change. The total entropy change is simply the sum of the system and the surroundings

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