1. The Nature of Acid-Base Equilibria

2. Properties of Acids and Bases
Sour taste (vinegar)
Bitter taste (baking soda)
React with some metal to form H2 gas (Mg(s) + 2HCl(aq)  MgCl2(aq) + H2(g)
Feels slippery (soap)
Turns blue litmus red
Turns red litmus blue
Colourless in phenolphthalein
Pink in phenolphthalein
Conduct electricity

3. Acids and Bases Arrhenius Acids and Bases
Acid: produce H+ (or H3O+) when dissolved in water
 H3O+ = hydronium ion, H+ + H2O  H3O+
 HCl(aq) + H2O  H3O+(aq) + Cl-(aq)
 Base: produce OH- when dissolved in water 
NaOH + H2O  Na+(aq) + OH-(aq)
Bronsted-Lowry Acids and Bases
Acid: proton donor
HF + H2O  H3O+ + F- (HF acts as acid, H2O acts as base)
Base: proton acceptor 
NH3 + H2O  NH OH- (NH3 acts as base, H2O acts as acid)
NB: H2O is amphoteric (can act as an acid and a base)

4. Conjugate Acid-Base Pairs
the formula of conjugate acids and bases differ by only one proton
Water
Conjugate Base (acetate ion) of Acetic Acid
Conjugate Acid of Water
Water

5. Conjugate Acid-Base Pairs
CH3COOH + H2O  CH3COO- + H3O+
acetic acid = acid (proton donor)
water = base (proton acceptor)
acetate ion = conjugate base of acetic acid
hydronium ion = conjugate acid of water
NH3 + H2O  NH OH-
ammonia = base (proton acceptor)
water = acid (proton donor)
ammonium = conjugate acid of ammonia
hydroxide = conjugate base of water

6. Identifying Acid-Base Conjugate Pairs
Ex:
HCN + H2O  H3O+ + CN-
HCN is the acid, CN- is its conjugate base
H2O is the base, H3O+ is its conjugate acid
CH3COO- + H2O  CH3COOH + OH–
H2O is the acid, OH - is its conjugate base
CH3COO- is the base, CH3COOH is its conjugate acid

7. Strengths of Acids and Bases
Strong Acids and Bases: complete ionization
HCl(aq) + H2O  H3O+(aq) + Cl-(aq)
NaOH + H2O  Na+(aq) + OH-(aq)
Strong acids and bases are good electrolytes
Weak Acids and Bases: incomplete ionization
HC2H3O2 + H2O ↔ C2H3O H3O+
NH3 + H2O ↔ NH4+(aq) + OH-(aq)
Weak acids and bases are poor electrolytes
A weak acid exists in equilibrium with its conjugate base.
A weak base exists in equilibrium with its conjugate acid.
Strength ≠ Concentration
Strength describes the degree of ionization while Concentration describes the number of moles in a volume of solution
i.e. 1.0 M HCl and 1.0 M H2CO3 (same concentrations but HCl is stronger acid)

8. Types of Acids Monoprotic Acids Diprotic Acids Triprotic Acids
can only donate one acidic proton
eg: HCl + H2O  H3O+ + Cl-
 Diprotic Acids
can donate two acidic protons
eg: H2SO4 + H2O  H3O+ + HSO4-
HSO H2O  H3O+ + SO42-
 Triprotic Acids
can donate three acidic protons
eg: H3PO4 + H2O  H3O+ + H2PO4-
H2PO H2O  H3O+ + HPO42-
HPO H2O  H3O+ + PO43-

9. pH Scale pH is a measure of the acidity of a substance
acidity is directly related to the [H3O+]
therefore pH is directly related to [H3O+]
pH is a logarithmic scale
Therefore battery acid is not just twice as acidic as lemon juice…it is 10x more acidic (101)….and battery acid is 100x (102) more acidic than vinegar

10. Why is Pure Water Neutral?
Self-ionization of water
H2O + H2O  H3O+(aq) + OH-(aq)
this reaction does not occur to any great extent.
[H3O+] = 1.00 x 10-7 mol/L
[OH-] = 1.00 x 10-7 mol/L
Because [H3O+] = [OH-] are equal, water is neutral.
Also, since pH = -log [H3O+]
pH = -log [1.00 x 10-7]
pH = 7
Also note pOH = 7.00

11. Ion Product Constant of Water, Kw
H2O  H+(aq) + OH-(aq)
Kw = [H+][OH-] The Ion Product Constant of Water
Kw = [1 x 10-7][1 x 10-7]
Kw = 1.0 x – its temp dependent)
Also, -logKw , or pKw = 14.00
Since Kw is the product of [H+] x [OH-], then…
pH + pOH = 14.00

12. Good Things to Know [H3O+] = [OH-] neutral [H3O+] > [OH-] acidic
[H3O+] < [OH-] basic

13. Calculating pH i.e. Determine the pH of a 0.1M solution of HCl.   
i.e. What is the pH of a M solution of H2SO4?
i.e. What is the pH of a 1M NaOH solution?

14. Calculating pH
 i.e. The pH reading of a solution is What is the hydrogen ion concentration?   
i.e. What is the hydrogen ion concentration for a solution with a pH of 4.62?

15. Calculating pH
 i.e. Find [H3O+] and [OH-] in a 2.5 mol/L nitric acid solution.   
i.e. Find [H3O+] and [OH-] in a 0.16 mol/L barium hydroxide solution.

16. Calculating pH
 i.e. Determine the [H+] of a mL solution that contains 2.6 g of NaOH
Water taken from a lake was found to have [H+]=3.2x10-5 M. Calculate the pH and pOH.   

17. Measuring pH acid-base indicator
a chemical substance that changes colour when the pH of the system changes.
Ex: litmus
pH meter
electronic instrument that measure the voltage between electrodes in a solution and displays the measurement as a pH.

18. HOMEWORK pg. 532 # 1-2 pg. 537 # 4-6 pg. 540 # 8-11 pg. 546 # 12-14