Type 1: Given initial concentrations and one equilibrium concentration

  • Write balanced, dissolution equation → Set up ICE Table below

        ○ I: initial concentrations

        ○ C: Change in concentration

       ○ E: Equilibrium concentrations

  • Solve for x
  • If question doesn’t state molarity of substance, assume that it is 0

Type 2: Given initial concentrations and K

  • Find Q using initial concentrations and compare to K

           ○ Q < K → reactants will have –nx and products will have +nx (products/forward reaction favored)

           ○ Q > K → reactants will have +nx and products will have –nx (reactants/reverse reaction favored)

  • On AP exam can ignore x
  • Shortcut using calculator

             ○ Y1 = value of K

             ○ Y2 = plug in entire equilibrium equation

             ○ Graph → 2nd Trace → #5 → don’t move cursor → enter x3

             ○ X-value will be the answer for x

             ○ Plug in value for x