ACIDS

1
ACIDS BASES

• Chapters 15 16

2
Properties of Acids

• Acids generally known by their SOUR TASTE
• exs vinegar, citrus fruits, apples, grape
  juice, vitamin C, sour milk

3
Properties of Bases

• Bases- like the opposite of acids
• exs household ammonia, sodium hydroxide, milk
  of magnesia, antacids, baking soda

4
ACIDS

• 1. Sour Taste.
• 2. Change color of acid/base indicators (pH
  paper).
• 3. React with active metals.
• 4. React with bases.

5
Acid Naming (Revisited)

• Binary Acid (Table 15.1, p. 454)- only 2
  different elements
• HF, HCl, HBr, HI, H2S
• 1. Begins with hydro-, 2. Root name of 2nd
  element follows, 3. Ends in suffix -ic.

6
Acid Naming Continued

• Oxyacids- acid that is a compound of H, O, and
  3rd element, see Table 15.2, p. 455
• Formula H polyatomic ion!
• Named for polyatomic ion!

7
Industrial Acids

• Sulfuric Acid (oxyacid)
• Nitric Acid (oxyacid)
• Phosphoric Acid (oxyacid)
• Hydrochloric Acid (oxyacid)
• Acetic Acid (oxyacid)

8
Strength of Acids

• Strong acid strong electrolyte
• Weak acid weak electrolyte
• Organic acids are usually weak, why does this
  make sense?

9
Types of Acids

• Besides being Binary or Oxyacid types
• MONOPROTIC vs. POLYPROTIC
• Mono only 1 proton (H)
• Poly more than 1 (H)

10
BASES

• 1. Bitter Taste.
• 2. Change color of acid/base indicators.
• 3. Feels slippery.
• 4. React with Acids.
• 5. Conduct electric current.

11
Strength of Bases

• See Table 15.4, p. 461 in text
• Strong base strong electrolyte
• Weak base weak electrolyte

12
Definitions of Acids and Bases

• 3 definitions of acids and bases
• 1. Arrhenius (Swedish chemist)
• 2. Brontsed-Lowry
• 3. Lewis
• See Table 15.6, p. 475 in text

13
Arrhenius Acids and Bases

• Swedish chemist Svante Arrhenius
• Acid chem. compound that increases conc. of H
  ions
• Base chem. compound that increases conc. of OH-
  ions

14
Arrhenius Acids and Bases

• Most narrow of 3 definitions
• acids produce HYDRONIUM ion in solution (H3O)
• see Table 15.3, p. 460 in text for strengths of
  acids (strong vs. weak examples)

15
Aqueous Solutions of Bases

• Most bases are metal cations with the hydroxide
  ion (OH-)
• Alkali metal bases completely dissociate (strong
  base) where the term alkaline comes from

16
Bronsted-Lowry Definition

• B-L Acid molecule or ion that is a proton (H)
  donor
• B-L Base molecule or ion that is a proton (H)
  acceptor
• Acid/Base Rxn H transferred from acid to base

17
Conjugate Acids and Bases

• Conjugate base molecule that remains after acid
  has given up the proton (H)
• Conjugate acid molecule that is formed when
  base gains a proton (H)

18
Amphoteric Compounds

• A compound that can act as either an Acid OR a
  Base
• Best known amphoteric compound WATER !!!!
• (Water is the weakest acid or base!!!!)

19
Neutralization Reactions

• When acids and bases react with each other they
  NEUTRALIZE each other!
• Neutralization reaction of hydronium and
  hydroxide ions to produce Water (neutral
  substance!)

20
Acid Rain

• Industrial pollution gases dissolve in
  atmospheric water to acid solutions in clouds
  that rain back to Earth

21
Lewis Acids and Bases

• Third definition is most broad
• Lewis Acid atom, ion , or molecule that accepts
  an electron pair to form a covalent bond (e- pair
  acceptor)

22
Lewis Acids and Bases (cont.)

• Lewis Base atom, ion, or molecule that donates
  an electron pair to form a covalent bond (e- pair
  donor)
• See Table 15.6, p. 475 for Summary of 3 Acid/Base
  Defs

23
The Concept of pH

• Water is a very weak electrolyte, therefore it
  forms H and OH-
• H3O and OH- concentrations in distilled water
  1.0x10-7 mol/L each

24
Ionization Constant of Water

• Kw H3O OH- 1.0 x 10-14 M2
• Neutral, Acidic, Basic Solutions
• Acidic H3Ogt OH-
• Basic H3Olt OH-

25
The pH Scale

• pouvoir hydrogene hydrogen power or H
• a more convenient way to express concentrations
  of H
• pH -log H3O
• See Fig. 16.3, p. 485 in text

26
Determining pH and Titrations

• Indicator compounds whose colors are sensitive
  to pH chgs.
• pH meter device that determines the pH of
  solution by measuring voltage between 2
  electrodes that are in the solution

27
TITRATION

• Uses Neutralization Reactions of Acids and Bases
• B/C acids bases react with each other you can
  use a neutralization reaction to determine/
  compare concentrations

28
TITRATION Definition

• The controlled addition and measurement of the
  amount of a solution of known concentration
  required to react completely with a measured
  amount of solution of unknown concentration.

29
Titration Terms

• Equivalence Point when 2 solutions used in
  titration are present in chemically equal amounts
  (total neutralization, no excess acid or base!!!!)

30
Titration Terms continued

• End Point point in titration at which an
  indicator changes color (end point of
  indicator)
• pH curves for titration (See Table 16.9, p. 499
  in text!)

31
Molarity and Titration

• In a titration 1 solutions molarity (M) is
  known, therefore the other solutions M can be
  calculated!
• Standard Solution solution containing precisely
  known concentration of solute

32
Setup for Titration

• 1. Standard solution of acid/base in buret for
  titration.
• 2. Unknown solution of acid/base in Erlenmeyer
  flask to be titrated. Also an indicator must be
  present to measure pH.