2. 18.2.1 Describe the composition of a buffer solution and explain its action.  What is a buffer solution?  It is an aqueous solution that resists a change in pH when a small amount of acid, base or water is added to it.  An acidic buffer solution can be made by mixing a weak acid together with the salt of that acid and with a strong base  (Basically, combining a weak acid with a salt containing its conjugate base)

3. 18.2.1 Describe the composition of a buffer solution and explain its action.  An alkaline buffer solution can be made by mixing a weak base together with the salt of that base and with a strong acid  (Basically, combining a weak base with a salt containing its conjugate acid)

4. 18.2.2 Solve problems involving the composition and pH of a specified buffer solution  Examples of buffer solutions:  NaCH 3 COO(aq) Na + + CH 3 COO -  CH 3 COOH(aq) CH 3 COO - (aq) + H + (aq)  K a =  [H + ] x [CH 3 COO - ] [CH 3 COOH]

5. 18.2.2 Solve problems involving the composition and pH of a specified buffer solution  NH 4 Cl (aq) Na + + CH 3 COO -  NH 3 (aq) + H 2 O (l) NH 4 + (aq) + OH - (aq)  K a = [OH - ] x [NH 4 + ] [NH 3 ]