1. Chapter 19
DHS Chemistry

3. There are many theories and definitions of acids and bases.

4. An acid is a molecule or ion that acts as a proton (hydrogen ion) donor.
HCl + H20  H30+ + Cl-
acid

5. A base is a molecule or ion that acts as a proton (hydrogen ion) acceptor.
HCl + NH3  NH4+ + Cl-
base

6. An acid produces hydronium (H30+) ions when dissolved in water.
Ex. HCl + H2O  Cl- + H3O+

7. A base produces hydroxide (OH- ) ions when dissolved in water.
Ex. NH3 + H2O  NH4+ + OH-

8. Acids that can contain multiple hydrogens to donate.
Match the terms with the probable acid
monoprotic H2SO4
diprotic H3PO4
polyprotic HCl

9. Acids that contain 1 ionizable hydrogen are monoprotic acids.
Ex. HCl, HBr

10. Acids that contain 2 ionizable hydrogens are diprotic acids.
Ex. H2SO4

11. Acids that contain 3 ionizable hydrogens are triprotic/polyprotic acids.
Ex. H3PO4

12. Some substances can act as both an acid and a base – these substances are considered amphoteric.
EX: HCl + H20  H30+ + Cl-  water as a base
acid base
NH3 + H20  NH4+ + OH-  water as an acid
base acid
H20 + H20  H30+ + OH-  water as an acid
pure water has H2O, H3O+, OH & base

13. (refer to your previous notes!)

14. (refer to your previous notes
(refer to your previous notes! Make sure you have those particular ones memorized, both their formula and their name!)

16. (refer to your previous notes!)

18. Hydronium H3O+ Hydroxide OH- A hydrogen ion in water H+ + H2O  H3O+
H+ and H3O+ used interchangeably
For acids
Hydroxide OH-
For bases

19. a measure of the number of hydronium or hydroxide ions is the pH scale
it is based on the concentration of hydrogen and hydroxide ions in solution
pH is defined as the negative logarithm of the hydrogen ion concentration

20. pH = -log([H+]) or -log([H3O+])
pOH = -log ([OH-])
[ ] = concentration (molarity)
notice pH is based on a log scale
log(base 10) is the power to which 10 must be raised to equal that number.

21. b n = x n = logb x Logarithm is an exponent 23 = 8 3 = log28
Then, 3 is called the logarithm of 8 with a base 2
3 = log28

22. 104 = 10,000 4 = log1010,000 We’ll use this concept for pH
The logarithm of 10,000 with a base 10 is 4
4 = log1010,000
We’ll use this concept for pH

23. 14 = pH + pOH

24. 0.001 M HCl
In calculator: -log(0.001)
(some calculators are a little different)
pH = 3

25. Because NaOH is a base, we’re calculating the pOH
0.01 M NaOH
Because NaOH is a base, we’re calculating the pOH
pOH = -log(0.01)
pOH = 2
14 = pH + pOH 2
pH = 12

26. 3.2 x 10-9 M HNO3
pH = -log(3.2 x 10-9)
pH = 8.49

27. the typical pH scale runs from 0 to 14 .

29. The concentration of an acid (or base) in solution can be determined by performing a neutralization reaction.
Recall neutralization…

30. The reaction of an acid with a base produces water and a class of compounds called salts.
HA + BOH  B A + H2O
ex.
HCl(aq) + NaOH(aq)  NaCl (aq) + H2O(l)
acid
base
salt
water

31. An indicator is used to show when neutralization has occurred.
An indicator is a substance that forms different colors in different pH solutions. Phenolphthalein is a common indicator used in acid-base titrations. It will change from colorless in acidic environments to pink in basic environments.

32. A measured volume of a solution of unknown concentration (acid or base) is added to an Erlenmeyer flask.
A solution of known molarity (acid or base) is added to a buret.

33. 3. Several drops of an indicator are added to the unknown solution
4. Measured volumes of a solution of known molarity (acid or base) are mixed into unknown solution until the indicator just barely changes to a different color.

34. The solution of known concentration is called the standard solution
The solution of known concentration is called the standard solution. The standard solution is added using a buret.
The process of adding a known amount of solution of known concentration to determine the concentration of another solution is called titration.
The point at which the indicator changes color is the end point of the titration.

35. This can also be done less “formally” using any volume measures
This can also be done less “formally” using any volume measures. The results won’t be as accurate, but it gets you close.
Example: (drops, substitute for mL)

39. aMAVA = bMBVB (similar to dilutions)
Remember, in order for the solution to be neutral,
Moles H30+ = moles OH-
a = # of H+ ions in acids
b = # of OH- ions in bases
M = Molarity (M)
V = volume
aMAVA = bMBVB (similar to dilutions)

40. a = __ for H2SO4 and b = __ for Ca(OH)2 2 2
1) Determine a and b for the following
a = __ for H2SO4 and
b = __ for Ca(OH)2 2 2

41. MA = 0.749 M 1(MA)(35.28 mL) = 1(1.008M)(26.23 mL)
2) It takes mL of a M NaOH solution to neutralize mL of a monoprotic acid solution. What is its molarity?
1(MA)(35.28 mL) = 1(1.008M)(26.23 mL)
MA = M

42. MB = 1.61 M 2(0.533 M)(23.40 mL) = 1(MB)(15.50 mL)
3) If mL of NaOH solution were neutralized with mL of M H2SO4, what is the concentration of the NaOH ?
2(0.533 M)(23.40 mL) = 1(MB)(15.50 mL)
MB = 1.61 M

43. 4) mL of M nitric acid is used to completely neutralize a 1.0 M NaOH solution. What volume of NaOH is present?
1(0.720 M)(25.00 mL) = 1(1.0 M)VB
VB = mL

44. Ex: A 25 mL solution of nitric acid is completely neutralized by 18mL of 1.0M NaOH. What is the concentration of the acid solution?

45. Ex: A 25 mL solution of nitric acid is completely neutralized by 18 mL of 1.0M NaOH. What is the concentration of the acid solution?
MA = ?? MB = 1M
VA = 25mL VB = 18mL
MAVA = MBVB rearranged to solve for MA MA= MBVB VA
(1M)(18mL) = 0.720M mL

46. What is the molarity of phosphoric acid if 15
What is the molarity of phosphoric acid if 15.0 mL of the solution is completely neutralized by 38.5 mL of M Al(OH)3?
It takes mL of a 1.32 x 10-3 M NaOH solution to neutralize a mL of a triprotic acid solution. What is the concentration of the acid?
0.385 M H3PO4
MB = 2.53 x 104 M

47. 3. What is the molarity of sodium hydroxide if 20
3. What is the molarity of sodium hydroxide if 20.0 mL of the solution is neutralized by 28.0 mL of 0.60 M HCl?
4. How many mL of 0.45 M HCl must be added to mL of 1.00 M Sr(OH)2 to make a neutral solution?
0.840 M NaOH
VA = mL

48. What is the molarity of phosphoric acid if 15
What is the molarity of phosphoric acid if 15.0 mL of the solution is completely neutralized by 38.5 mL of M Al(OH)3?
H3PO4 Al(OH)3
MA = ?? MB = 0.150M
VA = 15mL VB = 38.5mL
MAVA = MBVB rearranged to solve for MA MA= MBVB VA
(0.150M)(38.5mL) = 0.385M H3PO mL

49. 3. What is the molarity of sodium hydroxide if 20
3. What is the molarity of sodium hydroxide if 20.0 mL of the solution is neutralized by mL of 0.60 M HCl?
HCl NaOH
MA = 0.60M MB = ??
VA = 28.0mL VB = 20.0mL
MAVA = MBVB rearranged to solve for MB MB= MAVA VB
(0.60M)(28.0mL) = 0.840M NaOH mL