Chem 211 1st Edition Lecture 18 Outline of Last Lecture I. Le Châtelier’s PrincipleII. The Effect of a Change in ConcentrationOutline of Current Lecture I. The Effect of a Change in Pressure (Volume)II. The Effect of a Change in TemperatureIII. Temperature and KIV. Catalysts and EquilibriumV. The Synthesis of AmmoniaCurrent LectureI. The Effect of a Change in Pressure (Volume)A. Changes in pressure affect equilibrium systems containing gaseous components.B. Changing the concentration of a gaseous component causes the equilibrium to shift accordingly.C. Adding an inert gas has no effect on the equilibrium position, as long as the volume doesnot change.a) This is because all concentrations and partial pressures remain unchanged.D. Changing the volume of the reaction vessel will cause equilibrium to shift if ∆ngas ≠ 0.E. Changes in pressure (volume) have no effect on the value of K.II. The Effect of a Change in TemperatureA. To determine the effect of a change in temperature on equilibrium, heat is considered a component of the system.B. Heat is a product in an exothermic reaction (∆H°rxn < 0).C. Heat is a reactant in an endothermic reaction (∆H°rxn > 0).D. An increase in temperature adds heat, which favors the endothermic reaction.E. A decrease in temperature removes heat, which favors the exothermic reaction.III. Temperature and KA. The only factor that affects the value of K for a given equilibrium system is temperature.B. For a reaction with ∆H°rxn > 0, an increase in temperature will cause K to increase.C. For a reaction with ∆H°rxn < 0, an increase in temperature will cause K to decrease.D. The van’t Hoff equation shows this relationship:These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.IV. Catalysts and EquilibriumA. A catalyst speeds up a reaction by lowering its activationenergy. A catalyst therefore speeds up the forward andreverse reactions to the same extent.B. A catalyst causes a reaction to reach equilibrium morequickly, but has no effect on the equilibrium position.V. The Synthesis of AmmoniaA. Ammonia is synthesized industrially via the Haber process:B. There are three ways to maximize the yield of NH3:a) Decrease [NH3] by removing NH3 as it forms.b) Decrease the volume (increase the pressure).c) Decrease the
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