Chem Ch 16

• two solutes dissoved in a solvent that contain the same ion (example NaF and HF)
• HF (aq) + H2O (l) <-> F- (aq) + H3O (aq)
• NaF (s) --> Na+ (aq) + F- (aq)

the shift in equilibrium caused by the addition of a compound having a common ion

• pH = pKa + log [conjugate base] / [acid]
• the assumption that x << [HA]0 is used
• remember p just means -log
• can be used for acid or base, just DON'T MODIFY (use Ka)

• a solution that resists changes in pH
• consists of a weak acid or a weak base and its salt

• a substance which changes color with pH
• usually it is a weak organic acid
• it has two distinctly different colors from its ionized form and its nonionized form

the point when the indicator changes color

• HCl (aq) +NaOH (aq) --> NaCl (aq) +H2O (l)
• H3O+ (aq) + OH- (aq) --> H2O (l)
• use ICF table and moles
• what remains on F line will be used to calculate pH

• CH3COOH & NaOH
• CH3COOH (aq) + OH- (aq) --> CH3COO- (aq) + H2O (l)
• CH3COO- + H2O <-> CH3COOH + OH-
• will be a buffer zone around pH 3-6
• equivalence point about pH 9

• HCl & NH3
• H3O+ (aq) + NH3 (aq) --> NH4+ (aq) + H2O (l)
• Once the NH4+ is formed it will undergo equilibrium with water

• Unsaturated = Ksp > Q
• Saturated = Ksp = Q
• Supersaturated = Ksp< < Q
• typically, the smaller the Ksp the less soluble the salt -if they have the SAME ratios -
• the smaller the K the more it will want to precipitate

(s) - the number of moles of solute in one liter of a saturated solution (mol/L)

the number of grams of solute in one liter of a saturated solution (g/L)

the addition of a common ion to an insoluble salt will always decrease the solubility of the salt

if an anion is the conjugate base of a weak acid, solubility increases with decreasing pH (i.e. added an acid)