L28S09_Equi_mass_action+04-03-09

L28S09_Equi_mass_action+04-03-09 - Chem1A, L 28:...

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Unformatted text preview: Chem1A, L 28: "Equilibrium, Mass Action" Summary ∆G = ∆H -T∆S ∆H > 0 Endothermic ∆H > 0 Endothermic ∆H ∆S <0 <0 Exothermic More order No T Low T High T All T ∆H ∆S ∆S > 0 Less order ∆S > 0 Less order ©A.Pines,M.Kubinec,UCB ©A.Pines,M.Kubinec,UCB L24-7 L28-1 ChemQuiz© 28.1 CO2 (g) + CaO (s) CaCO3 (s) ∆H˚ ~ -200 KJ · mol-1 ∆S˚~ -200 J mol-1K-1 For the reaction: For what temperature range is the reaction spontaneous? spontaneous? A) < 1000 © 2001 A.Pines,M.Kubinec,UC Regents B) ~ 1000 C) > 1000 L28-2 Summary © A.Pines,M.Kubinec,UCB 1 Chem1A, L 28: "Equilibrium, Mass Action" Equilibrium aA+bB Phase Change H2O (g) H2O (l) Gas Phase 2 NO2 (g) N2O4 (g) (g H3O+ (aq) + Ac– (aq) (aq) AgCl (s) [Xi] L28-5 cC+dD Pi Aqueous HAc (aq) + H2O (l) aq) Heterogeneous Ag+ (aq) + Cl- (aq) Ag © 2001 A.Pines,M.Kubinec,UC Regents Law of Mass Action aA+bB c cC+dD d [C] [D] Products Reaction Q= = K(T) at Equ. a b Quotient Reactants [A] [B] Q<K Products Q=K EQUILIBRIUM Q>K Reactants L28-6 © 2001 A.Pines,M.Kubinec,UC Regents Vapor Pressure of Water P H2O (l) equ. equ. H2O (g) Pvap P V L G T L28-7 Q = PH2O = Pvap(T) = K K = 0.03 @ 25 C equ. equ. H2O (g) H2O (l) Pvap S Q = 1/PH2O = 1/ Pvap(T) = K’ 1/P © 2001 A.Pines,M.Kubinec,UC Regents © A.Pines,M.Kubinec,UCB 2 Chem1A, L 28: "Equilibrium, Mass Action" ChemQuiz© 28.2 H2O (l) H2O (g) P S L G T Which is true under standard conditions ? A) Q < K © 2001 A.Pines,M.Kubinec,UC Regents B) Q = K C) Q > K L28-8 ChemQuiz© 28.3 H2O (l) H2O (g) P S L G T K How does K vary with Temperature ? K K A) T © 2001 A.Pines,M.Kubinec,UC Regents B) T C) T L28-10 Approach and Maintenance Approach H2,O2 Equilibrium Unstable Stable Pi, [Xi] [X Stable H2O Monotonic Clock Oscillatory Chaotic L28-12 © 2001 A.Pines,M.Kubinec,UC Regents © A.Pines,M.Kubinec,UCB 3 Chem1A, L 28: "Equilibrium, Mass Action" ChemQuiz© 28.4 For the reaction: I2(s) I2 (g) what happens to the vapor color intensity when I2 (s) is added ? A) Increases B) Same C) Decreases © 2001 A.Pines,M.Kubinec,UC Regents L28-13 ChemQuiz© 28.5 For the reaction: I2(s) I2 (g) what happens to the vapor color intensity when T is raised ? A) Increases B) Same C) Decreases © 2001 A.Pines,M.Kubinec,UC Regents L28-15 Lecture Complete © 2001 A.Pines,M.Kubinec,UC Regents L28-17 © A.Pines,M.Kubinec,UCB 4 ...
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This note was uploaded on 04/24/2010 for the course CHEM 1A taught by Professor Nitsche during the Spring '08 term at University of California, Berkeley.

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