All Flashcards
How do you calculate ΔS° for a reaction?
ΔS°rxn = ΣnS°products - ΣnS°reactants, where n = stoichiometric coefficient and S° = standard molar entropy.
What is the effect of increasing the number of moles of gas in a reaction?
It usually results in a positive ΔS° (increased disorder).
What is the effect of a negative ΔS° and negative ΔH at low temperatures?
The reaction is spontaneous.
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).