Chem 211 1st Edition Lecture 15Outline of Last Lecture I. Reaction MechanismsII. The Rate-Determining Step of a ReactionIII. Correlating Mechanism with the Rate LawIV. Catalysis: Speeding up a ReactionV. EquilibriumVI. The Equilibrium ConstantVII. K and the Extent of ReactionOutline of Current Lecture I. The Reaction Quotient QII. Forms of K and Q and Heterogeneous EquilibriumIII. Kc and KpIV. Determining the Direction of ReactionV. Solving Equilibrium ProblemsVI. The Simplifying AssumptionCurrent LectureI. The Reaction Quotient QA. Q gives the ratio of product concentrations toreactant concentrations at any point in areaction.B. At equilibrium: Q = KC. For a particular system and temperature, the same equilibrium state is attained regardless of starting concentrations. The value of Q indicates how close the reaction is to equilibrium, and in which direction it must proceed to reach equilibrium.II. Forms of K and Q and Heterogeneous EquilibriumA. For an overall reaction that is the sum of two more individual reactions:a) Qoverall = Q1 x Q2 x Q3 x ….. andThese 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.b) Koverall = K1 x K2 x K3 x ……B. If the coefficients of a balanced equation are multiplied by a common factorC. A heterogeneous equilibrium involves reactants and/or products in different phases.D. A pure solid or liquid always has the same “concentration”, i.e., the samenumber of moles per liter of solid or liquid.E. The expressions for Q and K include only species whoseconcentrations change as the reaction approaches equilibrium665.F. Pure solids and liquids are omitted from the expression for Q or K.III. Kc and KpA. K for a reaction may be expressed using partial pressures of gaseous reactants instead ofmolarity.B. The partial pressure of each gas is directly proportional to its molarity.C. If the amount (mol) of gas does not change in thereaction, a) Dngas = 0 and Kp = Kc.IV. Determining the Direction of ReactionA. The value of Q indicates the direction in which a reaction must proceed to reach equilibrium.B. If Q < K, the reactants must increase and the products decrease; reactants → products until equilibrium is reached.C. If Q>K, the reactants must decrease and the products increase; products → reactants until equilibrium is reached.D. If Q = K, the system is at equilibrium and no further net change takes place.V. Solving Equilibrium ProblemsA. If equilibrium quantities are given, we simply substitute these into the expression for Kc to calculate its value.B. If only some equilibrium quantities are given, we use a reaction table to calculate them and find Kc.C. A reaction table showsa) the balanced equation b) the initial quantities of reactants and productsc) the changes in these quantities during the reactiond) the equilibrium quantitiesVI. The Simplifying AssumptionA. We assume that x([A]reacting can beneglected ifB. Kc is relatively small and/or [A]init isrelatively