Chem 162-2008 10th week recitation formula page

Chem 162-2008 10th week recitation formula page - - n r H o...

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CHAPTER 16 - SPONTANEITY, ENTROPY AND FREE ENERGY First law of thermodynamics: Energy can neither be created nor destroyed. Second law of thermodynamics: The entropy of the universe always increases in any spontaneous process. Third law of thermodynamics: The entropy of a perfectly ordered crystalline substance at 0 K is zero. Entropy describes the number of arrangements (positions and/or energy levels) available to a system. Entropy is (officially called chaos, disorder, randomness) positional freedom, or positional availability, or disorder, or being unconfined positionally or escape from positional confinement or freedom from positional confinement ΔG o = Σn p ΔG o f(products) - Σn r ΔG o f(reactants) ΔH o = Σn p ΔH o f(products)
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Unformatted text preview: - n r H o f(reactants) S o system = n p S o products- n r S o reactants S system = n p S products- n r S reactants S surr = -H system /T = H surr /T S univ = S sys + S surr Three ways to find G o : (1) G o = H o- TS o (or G = H - TS) At equilibrium G = 0 0 = H - TS) S system = H system /T Troutons rule: At normal B.P., S system = H system /T 87J mol-1 K-1 (2) G o = n p G o f(products)- n r G o f(reactants) (3) G 1 o + G 2 o = G T o (i.e., adding equations [Hesss law]) G = G o + RT ln(Q) (Q can be pressure or concentration) At equilibrium, G = 0 0 = G o + RT ln(K) G o = -RT ln(K) w max = G...
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