1. Acids and Bases
Ch. 15 p. 530

2. 5.1 What are the properties of acids? p. 530
Acids react with metals to produce hydrogen gas.
Word Equation:
Metal + acid  hydrogen gas
e.g. rxn of Mg with hydrochloric acid
Teacher notes: evolution of hydrogen demo

3. Properties of acids p. 531 Acids are electrolytes
A substance that dissolves in water to conduct electricity.

4. Arrhenius Acid “When an acid dissolves in water…..
it produces an hydronium ion
H3O+”

5. Review: Lewis Structures
Challenge: Draw the Lewis structure of the hydronium ion H3O+
See p. 203 for a reminder of how to draw the Lewis structure of a polyatomic ion.

6. Strong acids/ Weak acids
Strong acid = hydrochloric acid
HCl (stomach acid)
dissociates completely (100%)
Weak acid = acetic acid
CH3COOH (vinegar)
dissociates partially (equilibrium)
pHET sim: acid-base solutions

7. Arrhenius definition of bases
Base = Basic = Alkali = Alkaline
“When a base dissolves in water…..
it produces an hydroxide ion
OH-”

8. Review: Lewis Structures
Challenge: Draw the Lewis structure of the hydroxide ion OH-
See p. 203 for a reminder of how to draw the Lewis structure of a polyatomic ion.

9. Strong bases and weak bases
Examples:
Strong base = sodium hydroxide
NaOH (drain cleaner)
Weak base = ammonia
NH3 (glass cleaner)
1. end

10. Bronsted-Lowry definition
Acids are hydrogen-ion-donating substances, and…….
bases are hydrogen-ion-accepting substances.

11. Bronsted-Lowry definition
‘Proton’ = ‘hydrogen ion’
11. Acids are proton donors
e.g. hydrogen chloride (HCl)

12. Bronsted-Lowry definition
12. Bases are proton acceptors
e.g. water, in:
e.g. ammonia in:
ammonia + water 

13. Polyprotic acids
Can donate more than one proton e.g. sulfuric acid (diprotic)

14. Polyprotic acids
Can donate more than one proton e.g. phosphoric acid (triprotic)

15. Amphoteric substances
14. An amphoteric substance can act as an acid or a base.
e.g. compare the action of water in:
ammonia + water 
vs.

16. Water is amphoteric
water can act as an acid by donating a proton to a base
Ammonia + water 
Draw eqn on doc cam

17. Water is amphoteric
water can act as a base by accepting a proton from an acid
Hydrochloric acid + water 
Doc cam

18. Conjugate acids and bases
Conjugate acids and bases are the PRODUCTS of acid/base reactions.
Acid + base 
conjugate base + conjugate acid
See Table 3 p.537
Doc cam

19. Standards
CH5. Acids, bases, and salts are three classes of compounds that form ions in water solutions. As a basis for understanding this concept:
CH5. a. Students know the observable properties of acids, bases, and salt solutions.
CH5. b. Students know acids are hydrogen-ion-donating and bases are hydrogen-ion-accepting substances.
CH5. c. Students know strong acids and bases fully dissociate and weak acids and bases partially dissociate.
CH5. d. Students know how to use the pH scale to characterize acid and base solutions.

20. Logarithms*
Log Base 10
Log base 10, also known as the common logarithm or decadic logarithm, is the logarithm to the base 10.
The common logarithm of x is the power to which the number 10 must be raised to obtain the value x.
For example, the common logarithm of 10 is 1, the common logarithm of 100 is 2 and the common logarithm of 1000 is 3.
It is often used in various engineering fields, logarithm tables and handheld calculators.

21. Logarithms Resources Khan Academy: Logarithm Basics

22. 15.2 Indicators Litmus paper Red litmus paper turns blue in a base
Blue litmus paper turns red in an acid
pH paper and Universal Indicator solution
See color chart on fig 12 p. 546
Phenolphthalein
Clear solution turns pink in base

23. KWL: pH definition
avalueusedtoexpresstheacidityorbasicityofasolutionapHof7isneutralapHoflessthansevenisacidandapHofgreaterthansevenisbasic
A value used to express the acidity or basicity of a solution. A pH of 7 is neutral, a pH of less than seven is acid, and a pH of greater than seven is basic.
p.542
KWL pH

24. 15.2 Self Ionization of Water
[H3O+] = [OH−] = 1.00 × 10−7 M

25. Do you have a scientific calculator?
Read p. 539
Do you have a scientific calculator?

26. 15.2 Equilibrium constant
[H3O+][OH−] = Kw = (1.00 × 10−7)(1.00 × 10−7) = × 10−14

27. KWL: pH pH stands for ‘power of Hydrogen’
pH tells us how much hydronium ion is dissolved in solution
pH = - log10 [H3O+]
A change in one pH unit corresponds to 10 times change in conc of hydronium ion
e.g pH 2 has 10X more hydronium than pH 3
e.g pH 2 has 100X more hydronium than pH 4
Read Calculating pH from [H3O+] p. 543

28. 15.2 Calcualating pH
pH is not a linear scale, it is a logarithmic scale (The Richter scale is another example of a logarithmic scale) What is the pH of a M solution of HNO3, a strong acid? pH = - log[H3O+] See Skills Toolkit p. 543 Teacher notes: pH table vs [H3O+] table
6. Start w/ calc on Monday
ANS = pH = 4

29. Practice
What is the pH of a solution with a hydronium concentration of M?
(a calculator is not necessary to answer this question)
ANS: pH = 6

30. 15.2 Calculating [H3O+] from pH*
Sample Problem C What is the concentration of the hydronium ion in a sample of rain that has a pH of 5.05? The pH equation may be rearranged to calculate the hydronium ion concentration from the pH. [H3O+] = 10−pH

31. pH calcs
Calculating pH from [H3O+] p. 544 Practice #1,2 #3,4 (use pH + pOH = 14) Calculating [H3O+] from pH # 1-4
1,2 - monday

32. 15.3 Notes: Neutralization
Read sec 15.3 p
thereactionofanacidwithabasetoformasaltandwater
The reaction of an acid with a base to form a salt and water.
p.548
Gizmo: Titration

33. Acid-base reactions Acid + Base  ‘Salt’ + Water Example:
HCl + NaOH  NaCl + H2O
Overall:
H+(aq) + OH−(aq)  H2O(l)

34. pH Indicators p. 546
Indicators are organic dyes that change color in response to acid/base.
Indicator molecules absorb slightly different wavelengths of light depending on if they are in acidic or basic solution.

35. titration
amethodtodeterminetheconcentrationofasubstanceinasolutionbyaddingasolutionofknownvolume andconcentrationuntilthereactioniscompletedwhichisusuallyindicatedbyacolorchange
A method to determine the concentration of a substance in a solution by adding a solution of known volume and concentration until the reaction is completed, which is usually indicated by a color change. (p. 550)
1. Start with titration vid/read expt overview

36. Venn diagram: acid/base/neutral
Hydronium ion
Hydroxide ion
pH less than 7
pH equals 7
pH greater than 7
Proton donor
Proton acceptor
Electrolyte
non-electrolyte
Litmus paper turns red
Litmus paper turns blue
Phenolphthalein is clear
Phenolphthalein turns pink
reaction with metal
Review: Acid mind map