C21 acids, buffers + bases

• the pH scale is logarithmic
• an acid is a proton donor
• a base is a proton acceptor
• acid-base equilibria involve transfer of protons
• a strong acid/base is one that completely dissociates to ions when in solution
• a weak acid/base is one that partially dissociates to ions when in solution
• the pH scale measures hydrogen ion concentration
• water slightly dissociates
• $K_w$is derived from the equilibrium constant for the dissociation of water
• the value of $K_w$varies with temperature
• the dissociation constant of a weak acid is represented by $K_a$
• acid/base titrations involve an acid/base being added to a base/acid until an end point is reached, shown by an indicator
• a pH curve for a titration has the pH on the y axis and the volume of substance added on the x axis
• a buffer solution maintains an approximately constant pH despite dilution or addition of small amounts of acid/base
• acidic buffer solutions contain a weak acid and the salt of that weak acid
• basic buffer solutions contain a weak base and the salt of that weak base
• buffer solutions are used for keeping systems regulated in nature, as enzymes require a specific pH otherwise they denature
• the equation for pKa is pKa = -log(Ka)
• the equation for Kw is Kw = [OH-][H+]
• the concentration of OH- ions of a strong base is represented by [OH-]=[XOH]
• the equilibrium constant for the dissociation of water is represented by [OH-]=[H+]
• the concentration of H+ ions of a strong acid is represented by [H+]=[HA]
• the equilibrium constant of a weak acid is represented by Kc = [H+][A-]/[HA]
• the equation for pH is pH = -log[H+]