1. 1.) If a STRONG ACID is added to a buffer system…
Review:
1.) If a STRONG ACID is added to a buffer system…
H3O+ + HCO3 -  H2O + H2CO3
The strong acid reacts with the conjugate base of the buffer solution
2.) If a STRONG BASE is added…
OH- + H2CO3  H2O + HCO3-
The strong base reacts with the weak acid of the buffer solution

2. Finding the pH of a buffer solution:
What is the pH of a 1.00 Liter acetic acid / sodium acetate buffer with [CH3CO2H] = 0.70 M and [CH3CO2-] = 0.60 M? (CH3CO2H, Ka=1.8x10-5)
What buffering reaction would take place if sodium hydroxide were added to this buffer?
How many moles of NaOH could be added before the buffer stopped working?

3. Objectives:
1. Describe how to produce a buffer solution with certain pH

4. Preparing a Buffer Solution:
1. Buffers are prepared by combing an acid solution with a salt containing the conjugate base
ie. Mix hydrofluoric acid, HF, solution with sodium fluoride, NaF
You must also be sure to use a salt that is actually soluble in water! (alkali metals are the safest bet)

5. Preparing a Buffer Solution:
1. Buffers are prepared by combing an acid solution with a salt containing the conjugate base
2. pH is controlled primarily by the pKa of the acid being used.

6. Preparing a Buffer Solution:
1. Buffers are prepared by combing an acid solution with a salt containing the conjugate base
2. pH is controlled primarily by the pKa of the acid used.
3. pH is “fine tuned” by the ratio of acid : base

7. Preparing a Buffer Solution:
Which of the following acid-base pairs would be a suitable choice for the creation of a buffer solution with a pH of 4.3? In what ratio should they be?
HSO4- SO42- Ka=1.2x10-2 pKa=1.92
HC2H3O2 C2H3O21- Ka=1.8x10-5 pKa=4.75
HCO3- CO32- Ka=4.8x pKa=10.32

8. Buffer Creation: Available chemicals:
Unlimited 6 M stock solutions of acetic acid
Unlimited amounts of sodium acetate solid salt
Unlimited deionized water
Describe steps on how to produce 100 mL of a buffer with assigned pH. Be specific about how much 6 M acid solution to dilute and what mass of salt to add.
This should be types/written and turned in at the end of the period.

9. Acids and Bases