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### Delta S

Posted: Thu Feb 13, 2020 2:56 pm
What is the difference between Delta S, Delta S (total), and Delta S (surroundings)? How do we apply these concepts on an examination / question?

### Re: Delta S

Posted: Thu Feb 13, 2020 5:00 pm
Delta S is the change in the entropy of the system. Delta S (surroundings) is the change in entropy of the surroundings. Delta S (total) is Delta S plus Delta S (Surroundings). In a reversible reaction, delta S (surr) is equal to negative Delta S. In an irreversible reaction, Delta S(surr)=0.

### Re: Delta S

Posted: Sun Feb 16, 2020 3:17 pm
Delta S is equal to entropy so on a question when asked to calculate entropy you will use a delta s equation. Just normal delta s is the change in entropy, delta s surroundings is the change of entropy in the surroundings, and delta s total is the change of entropy of the surroundings and change of entropy of a system.

### Re: Delta S

Posted: Sun Feb 16, 2020 3:41 pm
Delta S of the system is the entropy of the system, Delta S of the surroundings is the entropy of the surroundings (usually just the opposite/negative of Delta S), and the Delta S (total) is 0 for isothermal reversible reactions and is usually equal to Delta S (sys) for irreversible reactions.

### Re: Delta S

Posted: Sun Feb 16, 2020 6:06 pm
Delta S (sys) is the entropy of the system, Delta S (surr) is the entropy of the surroundings. Delta S (sys) + Delta S (surr) = Delta S(total), where Delta S (total) is the total entropy of both the surroundings and the system.

### Re: Delta S

Posted: Sun Feb 16, 2020 9:18 pm
Delta S - regular delta S, usually concerns the system of the reaction
Delta S (surroundings) - usually equals negative delta S (system)
Delta S (total) - equals delta (system) + delta (surroundings)

### Re: Delta S

Posted: Sun Feb 16, 2020 9:33 pm
Delta S is the entropy of the system. Delta S surroundings is the entropy of the surroundings. Delta S total is the entropy of the surroundings and system combined.

### Re: Delta S

Posted: Sun Feb 16, 2020 10:19 pm
Delta S is equal to the entropy of the system whereas delta Ssurroundings is the entropy of the surroundings and so delta Stot is the entropy of the surroundings and system added together.

### Re: Delta S

Posted: Sun Mar 15, 2020 6:36 am
When using the equation (delta)S= C ln(T2/T1), How do you know which heat capacity to use?