1. PROPERTIES OF ACIDS & BASES

2. WHAT IS AN ACID?
A compound that donates a hydrogen ion (H+) when dissociated

3. ACID PROPERTIES aqueous solutions have a sour taste
change the color of acid-base indicators
when reacted with an active metal, releases hydrogen gas
Zn (s) + H2SO4 (aq)  ZnSO4 (aq) + H2 (g)

4. ACID PROPERTIES when reacted with base, produces salt and water
HCl (aq) + NaOH (aq)  NaCl (s) + H2O (l)
conduct electric current
Turns litmus paper red

5. STRONG VS. WEAK ACIDS Strong acids dissociate completely
Every H+ ion breaks off
Weak acids dissociate incompletely
A few H+ ions break off then reform

6. WHAT IS A BASE? A compound that accepts a hydrogen ion (H+) OR
contains OH- ion

7. BASE PROPERTIES aqueous solutions of bases have a bitter taste
bases change the color of acid base indicators
dilute aqueous solutions of bases feel slippery

8. BASE PROPERTIES when reacted with acid, produces salt and water
conduct electric current
Turns litmus paper blue

9. Learning Check Describe the solution in each of the following as:
1) acid 2) base or 3)neutral
A. soda
B. soap
C. coffee
D. wine
E. water
F. grapefruit

10. Relationship of [H3O+] and [OH-]
Section 1 What Are Acids and Bases?
Chapter 15
Relationship of [H3O+] and [OH-]

11. DIFFERENT DEFINITIONS
SHOULD BE MEMORIZED

12. ARRHENIUS
ACID
A chemical compound that increases the concentration of H+ ions in solution
Good for calculating pH
BASE
A chemical compound that increases the concentration of OH- ions in solution
Good for calculation pOH
Limited to bases containing OH-

13. HCl  H+(aq) + Cl-(aq) Arrhenius Definition NaOH  Na+(aq) + OH-(aq)
In aqueous solution…
Acids form hydrogen ions (H+)
water
HCl  H+(aq) + Cl-(aq)
In aqueous solution…
Bases form hydroxide ions (OH-)
water
NaOH  Na+(aq) + OH-(aq)

14. Brønsted-Lowry Classification, continued
Section 1 What Are Acids and Bases?
Chapter 15
Brønsted-Lowry Classification, continued
Brønsted-Lowry Acids Donate Protons, continued

15. BRONSTED-LOWRY ACID A molecule or ion that is a proton (H+) donor BASE
A molecule or ion that is a proton (H+) acceptor
Includes compounds w/o OH-

16. HCl + H2O  Cl– + H3O+ acid conjugate base base conjugate acid
Brønsted-Lowry
Acids are proton (H+) donors
Bases are proton (H+) acceptors
HCl + H2O  Cl– + H3O+
acid
conjugate base
base
conjugate acid

17. HCl + H2O  Cl– + H3O+
acid
conjugate base
base
conjugate acid

18. Acids and bases come in pairs...
A conjugate base is the remainder of the original acid, after it donates it’s hydrogen ion
A conjugate acid is the particle formed when the original base gains a hydrogen ion
General equation is:
HA(aq) + H2O(l) H3O+(aq) + A-(aq)
Acid Base Conj acid Conj base

19. Examples 1.HCl + NH3 
NH4+ + Cl– 2.OH– + HCN
 H2O + CN–
3. PO43– + HNO3 
NO3– + HPO42-
4.HCO3– + HCl 
H2CO3 + Cl–

20. Why don’t we like this definition?
LEWIS
ACID
Electron pair acceptor
BASE
Electron pair donator
Why don’t we like this definition?

21. HCl(aq) + H2O(l)  H3O+(aq) + Cl–(aq)
Hydronium Ion H3O+
Often the term H+ for convenience, it is more accurate to use H3O+
HCl(aq) + H2O(l)  H3O+(aq) + Cl–(aq) H Cl O – +

22. Amphoteric - can be an acid or a base
Ex.1- Water as a base
Amphoteric - can be an acid or a base
(ex. water)
H2O + HNO3  H3O+ + NO3– B A CA CB

23. Ex. 2- Water as an acid
NH3 + H2O  NH4+ + OH- B A CA CB

24. Acid-Base Titrations and pH

25. pH
pH < 7 is acidic
pH = 7 is neutral
pH > 7 is basic

26. [H+] = concentration in molarity
Calculating pH
pH = - log [H+]
pH = power of Hydrogen
[H+] = concentration in molarity

27. Calculating pOH pOH = - log [OH-] pOH = power of Hydroxide
[OH-] = concentration in molarity
pH + pOH = 14

28. CALCULATING pH FROM CONCENTRATION
SAMPLE PROBLEM A
What is the pH of a 1 x 10-3 M HCl solution?

29. SAMPLE PROBLEM B
What is the pH of a 2.5 x 10-2 M H2SO4 solution?

30. SAMPLE PROBLEM C
What is the pH of a 2.5 x 10-2 M NaOH solution?

31. [H3O+] CALCULATING CONCENTRATION FROM pH [H3O+] = 10-pH
[H3O+] = concentration of acid (N)
Look for your log button.
Above it – 10x
To access it,
hit 2nd F key
Hit log key

32. [OH-] = concentration of base (M)
[OH-] = 10-pOH
[OH-] = concentration of base (M)
[H3O+] [OH-] = 1.0 x 10-14

33. SAMPLE PROBLEM D
What is the concentration of a HCl solution with pH of 5.6?

34. SAMPLE PROBLEM E
What is the concentration of a Mg(OH)2 solution with pH of 5.6?

35. NEUTRALIZATION REACTIONS

36. NEUTRALIZATION REACTIONS
The reaction of an acid and a base to form salt & water
H+ ions react with OH- to form water
Predict products as in a double replacement rxn (partner swap)
HCl (aq) + NaOH (aq) 
H2O (l) + NaCl (s)

37. PRACTICE REACTIONS
HCl + LiOH 
HNO3 + Ca(OH)2 
H2SO4 + Al(OH)3 

38. PRACTICE REACTIONS HCl + LiOH  H2O + LiCl
2 HNO3 + Ca(OH)2  2 H2O + Ca(NO3)2
3 H2SO Al(OH)3  6 H2O + Al2(SO4)3

39. TITRATIONS
MA VA = MB VB

40. NORMALITY & NEUTRALIZATION REACTIONS
MA VA = MB VB
Where:
MA = molarity of acid
VA = volume of acid
MB = molarity of base
VB = volume of base

41. NORMALITY & NEUTRALIZATION REACTIONS
What volume of a 0.25 M HCl solution is needed to neutralize 36 mL of 0.30 Mg(OH)2 M?
Step 1: Start with what you know.
NA = (0.25 M) (1) = 0.25 N
VA = X mL
NB = (0.30 M) (2) = 0.60 N
VB = 36 mL