1. Chapter 15 Acids bases acids Sour Turns litmus red Reacts with some metals to produce H 2 Phenolphthalein-clear Corrosive Conducts electricity bases Bitter Turns litmus blue Slippery Phenolphthalein-pink Corrosive Conducts electricity

2. Arrhenius Acid produces hydronium ions (H 3 O + ) hydrogen ions (H + ) in water dissociate HCl(g) -----> H + (aq) + Cl - (aq) HCl(g) + H 2 O(l) -----> H 3 O + (aq) + Cl - (aq) HF(g) + H 2 O(l) -----> H 3 O + (aq) + F - (aq) H 2 SO 4 (aq) + H 2 O(l) --------> H 3 O + (aq) + HSO 4 - (aq)

3. Electrolytes dissociate into ions Strong electrolyte – completely dissociates K eq is large-lots of ions Weak electrolyte partially dissociates K eq is small, not many ions Strong acid – completely dissociates Ka is large-lots of ions Weak acid partially dissociates Ka is small, not many ions Ka =ionization constant

4. Strong Acids [H 3 O + ] HCl HNO 3 H 2 SO 4 HBr HI What is the hydronium ion [H 3 O + ] concentration in a.10 M HCl solution? HCl(g) + H 2 O(l) -----> H 3 O + (aq) + Cl - (aq)

5. Weak Acids [H 3 O + ] What is the hydronium ion concentration in a.10 M HF solution? (Ka =6.8 x 10 -4 ) HF(g) + H 2 O(l) H 3 O + (aq) + F - (aq)

6. Find Ka for weak acid A.10 M weak acid has a hydronium ion concentration of 3.0 x 10 -4 M? What is the Ka? (ionization constant)

7. Arrhenius Base produces hydroxide (OH - ) ion in water NaOH(s) -----> Na + (aq) + OH - (aq) Strong base-completely dissociates Kb is large-favors products Weak base-partially dissociates Kb is small-favors reactants

8. Strong Bases NaOH LiOH KOH RbOH CsOH Ca(OH) 2 Sr(OH) 2 Ba(OH) 2 What is the hydroxide ion concentration in a.10 M NaOH solution?

9. Weak Base NH 3 is a weak base NH 3 (g) + H 2 O(l) NH 4 + (aq) + OH - (aq) What is the hydroxide ion concentration in a 0.10 M NH 3 solution? (Kb for NH 3 is 1.8 x 10 -5)

10. Neutralization HCl(aq) + NaOH(aq) -------> H 2 O(l) + NaCl (aq) Acid + Base water + a salt H + (aq) + OH - (aq)-------> H 2 O (l) H 3 O + (aq) + OH - (aq)------->2 H 2 O (l) Titration process of adding an acid to a base or base to an acid Equivalence point - moles of H 3 O + (H + ) = moles of OH - Indicator changes color at a certain [ H 3 O + ] End point when color changes When titrating to neutrality End point and equivalence point should be very close (Choose an indicator that changes color when moles of H + = moles of OH - ) When neutralizing a strong acid with strong base the indicator phenolphthalein is usually used

11. Titration molarity of an acid or base or volume of an acid or base What volume of.10 M HCl is needed to neutralize 10. mL of.20 M NaOH? One to one ratio use MaVa=MbVb Not one to one ratio use stoichiometry

12. What volume of.10 M HCl is needed to neutralize 10. mL of.30 M Ca(OH) 2 ?

13. What is the molarity of an HCl solution if it takes 5.0 mL of.20 M NaOH solution to neutralize 8.0 mL of the HCl? What is the molarity of an H 2 SO 4 solution if it takes 5.0 mL of.20 M NaOH solution to neutralize 4.0 mL of the HCl?

14. Bronsted-Lowry acids and bases does not need to be in water Bronsted Acid Proton (H + ) donor strong acid –readily donates a proton- large Ka weak acid – does not readily donate a proton- small Ka Bronsted Base Proton (H + ) acceptor strong base –readily accepts a proton- large Kb weak base – does not readily accept a proton- small Kb

15. HCl (aq) + H 2 O (l) H 3 O + (aq) + Cl - (aq) NH 3 (aq) + H 2 O(l) NH 4 + (aq) + OH - (aq)

16. Conjugate acid/base pair To find conjugate base- remove H+ (proton) Acid conjugate base HF HC 2 H 3 O 2 HSO 4 - To find conjugate acid- add H+ (proton) Base conjugate acid OH - NH 3 CO 3 2-

17. H 2 O(l) + H 2 O(l) H 3 O+(aq) + OH - (aq) Keq = Kw = 1.0 x 10 -14 1.0 x 10 -14 = [H 3 O + ] [OH - ] Pure water [H 3 O + ] = [OH - ]

18. 1.0 x 10 -14 = [H 3 O + ] [OH - ] What is the hydronium ion concentration if the hydroxide ion concentration of a solution is 1.0 x 10 -2 ? What is the hydroxide ion concentration if the hydronium ion concentration of a solution is 2.0 x 10 -4 ?

19. Acid - more hydronium ions than hydroxide ions Base - more –hydroxide ions than hydronium ions

20. pH = –log[H 3 O + ] Log in base 10 number to which 10 must be raised to equal that number Log of.10 = ?.10 = 10 -1 log = -1 Log of.010 = ?.010 = 10 -2 log = -2 What is the pH of a solution that has a hydronium in concentration of.10 M? pH =1 What is the pH of a solution that has a hydronium in concentration of.010 M? pH =2

21. hydroniumhydroxidepHAcid/base 0.100 0.01 1.0 X 10 -7 1.0 x 10 -12 1.0 x 10 -9

22. What is the pH of a solution if the hydronium ion concentration is 2.5 x 10 -3 M ? Estimate On calculator enter -log[H 3 O + ] =

23. Given pH find hydronium ion concentration pH = 1 hydronium ion concentration =.10 M or 10 -1 M pH = 2 = =.010 M or 10 -2 M pH = 9 = 10 -9 M pH = 12 10 -12 M What is the hydronium ion concentration of a solution that has a pH of 4.8? On calculator enter 10 x (2 nd log button) - pH

24. pH scale 0_________________________________ 7_____________________________________14 acid neutral base (alkaline) H 3 O + > OH - OH - > H 3 O + The lower the pH the more acidic The higher the pH the more basic