Unit 13: Solutions & Equilibrium Section 4: Chemical Equilibrium

Equilibrium: two opposing processes occurring at the same rate to achieve balance Players enter and leave the game, but… the same total number of players on field.

Club Equilibrium (200 max) 200 VIP 180 (20 max) 20 RateIN equal Con-Con Requal Club Equilibrium (200 max) At Equilibrium: Concentrations: VIP (20 max) 200 180 constant Rates: 20 equal 200 (Club) RateIN 180 180 equal 20 20 RateOUT 0 (VIP)

Con-Con Requal H2O(l) ⇄ H2O(g) Phase Change Equilibrium

Rate of Crystallization Saturated Solution Equilibrium Rate of Solvation = Rate of Crystallization Con-Con Requal total moles of dissolved NaCl remains constant total moles of undissolved NaCl(solid) remains constant

Concentrations of prod’s/react’s remain constant, but not equal Ratef(N2O4) Rateforward = Ratereverse Rater(NO2) Dynamic Equilibrium ⇄ N2O4(g) 2 NO2(g) Concentrations of prod’s/react’s remain constant, but not equal

Quick Quiz! 1) When a reaction has reached equilibrium, reactants and products … A) have stopped reacting. B) continue forming. C) have equal concentrations. D) decrease in concentration. 7

A B ⇄ Quick Quiz. 100 2) A reaction starts with 100 molecules of reactant and no product. As it approaches equilibrium, the forward rate will ________ and the reverse rate will ________. A) remain constant , increase B) decrease , remain constant C) increase , decrease D) decrease , increase 8

A B ⇄ Quick Quiz. 100 3) A reaction starts with 100 molecules of reactant and no product. At equilibrium, the amount of product B will be… A) greater than A B) less than A C) equal to A D) constant 9