1. Warm-Up What is an acid? What is a base?
*Turn in your Lemonade POGIL (extra credit)
*Get out your Molarity Practice
What is an acid?
What is a base?

2. Acids & Bases

3. Acid Properties Affect the color of indicators
Neutralize bases to form water
Acid (aq) + Base (aq)  Salt (aq) + H2O (l)
React with metals to produce hydrogen gas
Metal (s) + Acid (aq)  Salt (aq) + H2 (g)
Taste sour
Ex: Citric Acid (C6H8O7)

4. Acid Strength
Strong acids completely dissociate in water, meaning all the molecules become ions
HCl (aq) + H2O (l)  H3O+ (aq) + Cl- (aq)
7 of these: HCl, HBr, HI, HNO3, H2SO4, HClO3 HClO4
Weak acids do not dissociate easily, meaning only a few molecules become ions
HC2H3O2 (aq) + H2O (l) ↔ H3O+ (aq) + C2H3O2- (aq)
Common: H2CO3, HC2H3O2
H3O+ = Hydronium ion, same thing as H+ (aq)

5. Base Properties Affect the color of indicators
Neutralize acids to form water
Feel slippery
Ex: Soaps
Taste bitter
Ex: Green vegetables

6. Base Strength Strong bases produce hydroxide ions in a solution
Ca(OH)2 (aq)  Ca2+ (aq) + 2 OH- (aq)
Ex: LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2
Weak bases do not dissociate in solution
Ex: NH3, CO32-, ClO-
Strong Bases= Group 1 and Group 2 hydroxides (except Beryillium and Magnesium)
Lithium, rubidium, cesium and francium hydroxides are not normally used in lab because they are expensive.

7. Types of Acids & Bases Arrhenius Brønsted-Løwry
Acid – a substance that can donate an H+ ion
Base – any substance that can accept an H+ ion (has a lone pair)
H+ ions are protons!
Acid – a substance that can donate an H+ ion when dissolved in water
Base – a substance that can donate a OH- ion when dissolved in water
Acids & Bases defined by 3 different Theories:
Bronsted-Lowry
Arrhenius
Lewis—Acids are electron pair acceptors; Bases are electron pair donors

8. Conjugate Pairs
Pairs that differ by only one proton (H+) are called conjugate pairs
A strong acid will make a weak conjugate base
A weak acid will make a strong conjugate base
Reversible reactions have an acid and base on both sides
Reaction equilibrium will favor the side with the weaker acid and base
The stronger the acid, the stronger its desire to dissociate (separate into ions). The resulting basic ion is weak because it does not want to reform the strong acid.
If a strong acid had a strong conjugate base, then the base would quickly re-associate itself with a hydrogen proton. This reverses what the acid just did—dissociate itself from a hydrogen proton!
Weak Acid + Weak Base <--> Strong Conj. Base + Strong Conj. Acid
LEFT SIDE FAVORED!

9. Warm-Up
What are the conjugate bases of these acids? (Hint: do acids accept or donate H+?) HI
HSO4-
H2CO3
HPO42-

10. Last Nights Homework C2H3O2- (aq) + H2O (l) ↔ HC2H3O2 (aq) + OH- (aq)
 NH4+ (aq) + H2O (l) ↔ NH3 (aq) + H3O+ (aq)
 C6H5NH2 (aq) + NH3 (aq) ↔ C6H5NH3 (aq) + NH2- (aq)

11. Last Nights Homework

12. pH Scale
pH is a measurement of the concentration of H+ ions in solution
pH = -log[H+] [H+] = 10-pH
pOH is a measurement of the concentration of OH- ions in solution
pOH = -log[OH-] [OH-] = 10-pOH
In pure water, pH and pOH are both 7
Kw = [H+][OH-] = 1 x 10-14
pH + pOH = 14
Kw= the autoionization constant of water

13. pH Conversions

14. Practice
If [H+] = 1.0 x 10-7 M, then what is the pH?
pH = 7.0

15. Practice
If [OH-] is 5.01 x 10-4 M, what is the pOH?
pOH = 3.30

16. Practice
In household bleach, the concentration of OH- ions is 5.0 x 10-2 M. What is the pH?
pOH = 1.3
pH = 12.7

17. pH Indicators
Litmus Paper
Universal Indicator

18. pH Indicators
Methyl Red
Bromothymol Blue
Phenolphthalein