Supplemental Instruction 1060 Hixson-Lied Student Success Center 294-6624 www.si.iastate.edu Chapter 15 Chemical Equilibrium-2 Supplemental Instruction Iowa State University Leader: Alarm Cho Course: Chem 178 Instructor: John Verkade Date: Sep. 20, 2009 Chemical Equilibrium - Heterogeneous Equilibria PbCl2(s) Pb2+(aq) + 2Cl-(aq) Kc = CaCo3(s) CaO(s) + CO2(g) Kc = - Calculating Equilibrium Constants When concentrations are known ICE table sample exercise 15.9 H2(g) + I2(g) HI(g) Initial 1 x 10-3 M 2 x 10-3 M 0M Change Equilibrium 1.87 x 10-3 M - Applications of Equilibrium Constants Reaction Quotient Q = K: Q << K: Q >> K: Calculating Equilibrium concentrations When concentrations are known ICE table sample exercise 15.12 H2(g) + I2(g) HI(g) Initial 1 x 10-3 M 2 x 10-3 M 0M Change Equilibrium- Le Châtelier’s Principle “If a system at equilibrium is disturbed by a change in temperature, pressure, or the concentration of one of the components, the system will shift its equilibrium position so as to counteract the effect of the disturbance.” Change in concentration – Haber Process N2(g) + 3H2(g) 2NH3(g) Change in volume or pressure N2O4(g) 2NO2(g) Change in temperature Co(H2O)62+(aq) + 4Cl-(aq) CoCl42-(aq) +6H2O(l) ∆H > 0 Endothermic Exothermic - Effect of
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