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Define Entropy (S).

A measure of the disorder or randomness of a system.

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Define Entropy (S).
A measure of the disorder or randomness of a system.
Define Absolute Entropy (S°).
The entropy of a substance at standard conditions (1 atm and 273 K).
Define Change in Entropy (ΔS°).
The change in disorder during a reaction; the difference between the entropy of the products and the reactants.
What is a state function?
A property that depends only on the current state of the system, not on how it got there; it's pathway-independent.
Give examples of state functions.
Altitude change, enthalpy (H), and entropy (S).
Differentiate between a positive and negative ΔS°.
ΔS° > 0: Reaction increases disorder. | ΔS° < 0: Reaction decreases disorder.
Compare the entropy of solids, liquids, and gases.
Solids have the lowest entropy, liquids have intermediate entropy, and gases have the highest entropy: S<sub>solid</sub> < S<sub>liquid</sub> < S<sub>gas</sub>.
How do you calculate ΔS° for a reaction?
ΔS°<sub>rxn</sub> = ΣnS°<sub>products</sub> - ΣnS°<sub>reactants</sub>, where n = stoichiometric coefficient and S° = standard molar entropy.