Chem 113 1st Edition Lecture 20Outline of Last Lecture I. Equilibrium trending towards equal ratesII. Le Châtelier’s PrincipleIII. The Effect of a change in concentrationIV. The Effect of a change in Pressure (Volume)Outline of Current Lecture V. Solving Equilibrium ProblemsCurrent LectureI. Solving Equilibrium Problemsa. Do you know the equilibrium quantities?i. Yes: substitute into Kc expression and calculateb. Do you know some of the quantities?i. Yes: Use a reaction table to calculate quantities and find Kcc. Steps to Solving Equilibrium Problemsi. Write the balanced equationii. Write the expression for the reaction quotient Q or K1. When the reaction direction is not known, compare Q to Kiii. Convert all amounts into the correct units (M or atm)iv. Set up the reaction table (RICE)1. Reaction2. Initial quantities of reactants and products3. Changes4. Equilibrium quantitiesv. Check the sign of x, the change in the concentration (or pressure)d. Solving for x and equilibrium quantitiesi. Substitute the quantities into the expression for Qii. To simplify the math, assume that x is negligible1. [A]init-x=[A]eq≈[A]initiii. Solve for x1. Check that the assumption that x is negligible by justifying with <5% error; if not, solve quadratic equation for x2. Find the equilibrium quantitiesThese 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.a. Check to see that the calculated values give the known value for Kb. Equilibrium amounts are calculated by adding the change to the initial
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