L29S09_Equi_Temp_Lechatelier_04-06-09

L29S09_Equi_Temp_Lechatelier_04-06-09 - Chem 1A, L30:...

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Unformatted text preview: Chem 1A, L30: "Equilibrium, Temp, LeChatelier" Equilibrium Phase Change H2O (l) H2O (g) Gas Phase 2 NO2 (g) Law of Mass Action aA+bB cC+dD [C]c [D]d Products Previously Pi N2O4 (g) (g H3O+ (aq) + Ac– (aq) (aq) AgCl (s) aA+bB cC+dD Reaction Q= = K(T) at Equ. Quotient Reactants [A]a [B]b Q<K [Xi] L17-4 Aqueous HAc (aq) + H2O (l) aq) Heterogeneous Ag+ (aq) + Cl- (aq) Ag © A.Pines,M.Kubinec Products © A.Pines,M.Kubinec Q=K EQUILIBRIUM Q>K Reactants L17-5 Vapor Pressure of Water P Equilibrium Approach and Maintenance Approach H2,O2 Unstable H2O (l) equ. equ. H2O (g) Pvap P V L G T Monotonic © A.Pines,M.Kubinec Q = PH2O = Pvap(T) = K H2O (g) equ. equ. Stable Pi, [Xi] [X Stable H 2O H2O (l) Pvap S Q = 1/PH2O = 1/ Pvap(T) = K’ 1/P © UC © 2001Regents A.Pines,M.Kubinec,UCB Clock Oscillatory L24-6 Chaotic L29-1 L17-10 Summary Effect of P, V, T, n 2 NO2 (g) NO N2O4 (g) Equilibrium At 25º C, K ~ 6.8, ∆Hº = -57.2 kJ mol-1 Exothermic Q= PN2O4 P2NO2 = K at Equilibrium (T) L29-3 © 2001 A.Pines,M.Kubinec,UCB ©A.Pines,M.Kubinec,UCB 1 Chem 1A, L30: "Equilibrium, Temp, LeChatelier" ChemQuiz© 29.1 The volume is doubled by opening the valve. As the system approaches equilibrium the color intensity will …? A) Increase B) Same © 2001 A.Pines,M.Kubinec,UCB C) Decrease L29-4 Le Châtelier’s Principle A system in equilibrium subjected to a stress will react in a direction that tends to reduce the stress Q=K Q>K Q=K ∆V ∆P ∆Q © 2001 A.Pines,M.Kubinec,UCB L29-6 ChemQuiz© 29.2 Which strategy can best reverse CO blood poisoning? poisoning? Hb(O2)4 + 4 CO Hb( 2 Hb(CO)4 + 4 O2 Hb( CO) L29-7 A) Increase PO B) Cool off C) Remove Hb © 2001 A.Pines,M.Kubinec,UCB ©A.Pines,M.Kubinec,UCB 2 Chem 1A, L30: "Equilibrium, Temp, LeChatelier" ChemQuiz© 29.3 The temperature for 2 NO2 (g) N2O4 (g) is raised. What happens to the color intensity at equilibrium? A) Increase B) Same © 2001 A.Pines,M.Kubinec,UCB C) Decrease L29-9 Ammonia Synthesis (Haber-Bosch 1910) (HaberN2 (g) + 3 H2 (g) (g) (g) 2 NH3 (g) (g) ∆H ~ -92 kJ mol-1 Slow at 25o C. High T means low K: C. Raise P Actual Conditions: T~ 500 oC P~ 200 atm Actual L29-11 © 2001 A.Pines,M.Kubinec,UCB Multiple Equilibria A ∆ H1 K1 B B [ C] [A ] ∆ H2 K2 C A ∆ H3 K3 C K3 = = [C][B] ][B [A][B] ][B = K1 K2 ∆H3 = ∆H1 + ∆H2 © 2001 A.Pines,M.Kubinec,UCB L29-12 ©A.Pines,M.Kubinec,UCB 3 Chem 1A, L30: "Equilibrium, Temp, LeChatelier" ChemQuiz© 29.4 For the molecular rearrangement shown, how does K depend on T? K K A ∆ H1 B ∆ H2 C K A) T © 2001 A.Pines,M.Kubinec,UCB B) T C) T L29-13 ChemQuiz© 29.5 Consider the equilibria: Ni(H20)62+ Ni(H20)62+ Ni(NH3)62+ 6 NH3 K1 3 en K3 en en NH3 NH Ni(NH3)62+ Ni(en)32+ What is the color of K2 ? Ni(en)32+ A) Blue © 2001 A.Pines,M.Kubinec,UCB B) Violet C) Can’t tell Can’ L29-15 Lecture Complete © 2001 A.Pines,M.Kubinec,UCB L29-17 ©A.Pines,M.Kubinec,UCB 4 ...
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