University:
Eastern Kentucky University
Course:
CHE 111 | General Chemistry
Academic year:

2022
Views:

245

Pages:

2
Author:

rezancuk2j

Unit 7: Equilibrium Introduction to Equilibrium ● Chemical Equilibrium: the state where the concentrations of all reactants and products remain constant with time ○ Forward and reverse reactions are still occurring, just at equal rates Reaction Quotient and Equilibrium Constant for reaction aA + bB → cC + dD ● K is the value the equation will have at equilibrium ● Q is the value of the equation at any given time, no matter if the reaction is at equilibrium or not ● If Q > K: the system will shift left to attain equilibrium by decreasing product concentration while increasing reactant concentration ● If Q = K: the system is at equilibrium ● If Q < K: the system will shift right to attain equilibrium by increasing product concentration while decreasing reactant concentration Calculating the Equilibrium Constant ● Calculating Kc involves concentration [molarity] ● Calculating Kp involves pressure [atm] ● Do not include solids and liquids when they are the solvent bc densities stay same ● Include liquids when they are the solute and gases Magnitude of the Equilibrium Constant (K) ● K is a measure of the extent of the reaction ● If K>1, products are favored ● If K<1, reactants are favored Le Chatelier’s Principle ● When concentration of reactant/product is increased, the reaction shifts toward direction that allows it to use up the added substance ● When concentration of reactant/product is decreased, the reaction shifts toward direction that allows it to create the substance that has been removed ● When external pressure is increased, the reaction shifts to the side with fewer gas molecules ● When external pressure is decreased, the reaction shifts to the side with more gas molecules ● For temperature, depends on whether reaction is exothermic or endothermic Solubility Equilibrium ● Ksp is used to describe the solubility of an ionic compound, Ksp is more commonly known as the solubility product ● Ksp can be used to predict if a compound is soluble which is indicated by a Ksp>1. If the Ksp<1 then the compound is insoluble. ● Factors like pH and temperature affect the value of K and Ksp ● Common Ion Effect: Once the salt with the same ion is added to a solution the reaction shift in the opposite in the other direction