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L32S09_Hetero_equil+04-13-09

L32S09_Hetero_equil+04-13-09 - CHEM 1A...

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Unformatted text preview: CHEM 1A, L32: "Heterogeneous Equilibrium" Lab 8: Solubility and Spontaneity •Goal: Determine the solubility product, Ksp, for Borax. Create a Van’t Hoff plot to determine ∆Hº, Van’ ∆ Sº, and ∆ Gº •Tools and Skills: Titrations © 2004 M.Kubinec, A. Pines L32-1 Heterogeneous Equilibrium, Gases, Liquids, Solids Solubility of gases in water CO2 (g) Q= CO2 (aq) aq) Henry’s Law, Solubility [x] = K Px K: mM X(aq) per atm X X(aq) Xe 4.4 N2 0.7 O2 1.3 CO2 NH3 30 > 104 Summary CO2 CO2(aq) aq) Gas He K L26-4 Ar 1.5 [CO2 (aq)] aq)] PCO2 = K (T) Equ. Equ. 0.4 Carbonated drinks, “Bends” during diving ©A.Pines,M.Kubinec, UCB Like dissolves Like, Hydrophilic, Hydrophobic. L26-5 ©A.Pines,M.Kubinec, UCB Solubility of Ionic Solids BaSO4 (s) BaSO Ba2+ (aq) aq) + SO42- (aq) aq) Conductometric Titration Ba(OH)2 (aq) = Ba2+ (aq) + 2 OH- (aq) Ba( aq) aq) aq) H2SO4 (aq) = 2 H+ (aq) + SO4-2 (aq) aq) aq) aq) Ba2+ (aq) + SO4-2 (aq) = BaSO4 (s) aq) aq) BaSO (s) 2 H+ (aq) + 2 OH- (aq) = 2H2O aq) aq) Ba2+ OH- H2SO4 Q= [Ba2+] [SO42-] = K sp(T) Equ [Ba [SO Ksp = 1.1 x 10-10 x = [Ba2+] = [SO42-] [Ba [SO x2 = 1.1 x 10-10, x ~ 10-5 M ©A.Pines,M.Kubinec, UCB SO42Ba2+ BaSO4 L34-10 ©A.Pines,M.Kubinec, UCB L34-14 Heterogeneous Equilibrium Gases, Liquids, Solids Solubility of gases in water CO2 (g) Q= CO2 (aq) aq) = K (T) Equ. Equ. CO2 CO2(aq) [CO2 (aq)] aq)] PCO2 © 2004 M.Kubinec, A. Pines L32-3 © 2004 M.Kubinec, A. Pines 1 CHEM 1A, L32: "Heterogeneous Equilibrium" Henry’s Law, Solubility [x] = K Px Gas He K 0.4 Ar 1.5 K: mM X(aq) per atm X X(aq) Xe 4.4 N2 0.7 O2 1.3 CO2 NH3 30 > 104 Separations: Hydrophobic, Hydrophilic ~ ‘Likes dissolve Likes’ Hydrophobic, Likes’ © 2004 M.Kubinec, A. Pines [S]L1 coefficient = K ‘partition coefficient’’ [S]L2 L32-4 ChemQuiz© 32.1 A solution has equal concentrations of He (aq) and N2 (aq). aq) aq) Which is true ? 1) PHe < PN2 © 2004 M.Kubinec, A. Pines 2) PHe = P 2 N 3) PHe > PN 2 L32-5 ChemQuiz© 32.2 On a warm day, a can of carbonated beverage expands. From this, we expands. conclude that the dissolution of CO2 is.... CO2 (g) CO2 (aq) aq) 1) Exothermic © 2004 M.Kubinec, A. Pines 2) Isothermic 3) Endothermic L32-7 © 2004 M.Kubinec, A. Pines 2 CHEM 1A, L32: "Heterogeneous Equilibrium" Solubility of Ionic Solids BaSO4 (s) BaSO 2 Ba2+ (aq) + SO4-(aq) aq) aq) Q= [Ba2+] [SO4 - = K sp(T) Equ [Ba [SO 2 ] Ksp = 1.1 x 10-10 x= [Ba2+] [Ba = [SO4 -] [SO 2 x2 = 1.1 x 10-10, x ~ 10-5 M © 2004 M.Kubinec, A. Pines SO4 Ba2+ 2- BaSO4 (s) (s) L32-9 ChemQuiz© 32.3 Which of the following will be required in the least amount to dissolve a 1.0 mg speck of BaSO4 BaSO BaSO4 1) 0.1M H2SO4 © 2004 M.Kubinec, A. Pines 2) 0.01M BaCl2 3) H2O BaCl L32-10 Common Ion Effect -Le Châtelier BaSO4 (s) BaSO 2 Ba2+ (aq) + SO4-(aq) aq) aq) x x (0.1 + x) = Ksp 0.1 + x = 1.1 x 10-10 x ≈ 10-9 M © 2004 M.Kubinec, A. Pines L32-12 © 2004 M.Kubinec, A. Pines 3 CHEM 1A, L32: "Heterogeneous Equilibrium" Conductometric Titration Ba(OH)2 (aq) = Ba2+ (aq) + 2 OH- (aq) Ba( aq) aq) aq) H2SO4 (aq) = 2 H+ (aq) + SO42 (aq) aq) aq) aq) -2 H2SO4 Ba2+ (aq) + SO-2 (aq) = BaSO4 (s) aq) BaSO (s) 4 aq) 2 H+ (aq) + 2 OH- (aq) = 2H2O aq) aq) Ba2+ OHL32-13 © 2004 M.Kubinec, A. Pines ChemQuiz© 32.4 For the titration of Ba(OH)2 Ba( solution with H2SO4, which is the correct plot of conductance vs. added H2SO4? 1) 2) H2SO4 © 2004 M.Kubinec, A. Pines 3) H2SO4 H2SO4 L32-14 Lecture Complete © 2004 M.Kubinec, A. Pines L32-16 © 2004 M.Kubinec, A. Pines 4 ...
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