1. Agenda: 5/20

2. ACIDS & BASES Important Aqueous Solutions

3. NC Essential Standards 3.2.1 Classify substances using the hydronium and hydroxide concentrations Distinguish between acids and bases based on formula and chemical properties Differentiate between concentration (molarity) and strength (degree of dissociation) Use pH to identify acids and bases. Interpret pH scale in terms of the exponential nature of pH values in terms of concentrations. Relate the color of indicator to pH using ranges provided in a table. Compute pH, pOH, [H ⁺] and [OH⁻] 3.2.2 Distinguish properties of acids and bases related to taste, touch, reaction with metals, electrical conductivity, and identification with indicators such as litmus paper and phenolphthalein.

4. Overview of Key Concepts http://ed.ted.com/on/j4JlNr0Y#watch Introduction 5 minutes

5. Properties of acids and bases http://ed.ted.com/lessons/the-strengths-and-weaknesses- of-acids-and-bases-george-zaidan-and-charles-morton http://ed.ted.com/lessons/the-strengths-and-weaknesses- of-acids-and-bases-george-zaidan-and-charles-morton Notes: Make 4 columns to easily jot down notes from the video Acid propertiesBase properties Examples: StrongWeak Distinguish properties of acids and bases related to taste, touch, reaction with metals, electrical conductivity, and identification with indicators such as litmus paper and phenolphthalein. Note: Think H+ ions when protons are used.

6. Review: Names and Formulas Common acids that you must know All are dissolved in water (aqueous solutions) HCl HBr HF HNO ₃ H₂SO₄ HC₂H₃O₂ H₂CO₃ H₃PO₄

7. Review: Names and Formulas Common bases that you must know: NaOH Mg(OH) ₂ NH₃

8. Acid & Base demonstrations http://www.youtube.com/watch?v=ti_E2ZKZpC4 Introduction - properties (5 minutes) http://ed.ted.com/on/j4JlNr0Y

9. Arrenhius Definition of Acids and Bases Acids release H⁺ ion Also known as hydronium ions (H₃O⁺) Bases release OH⁻¹ (hydroxide) ions Other definitions: Bronsted Lowery Lewis

10. pH scale

11. pH values pH = - log [H ⁺]

12. pH Scale Strong Acids Weak & Dilute Acids Weak & Dilute Bases Strong Bases Neutral ⇓

13. Chemistry Reference Tables What do these formulas mean?

14. Ions in Solutions Neutral [H ⁺] [OH ⁻] In water: [H ⁺]= [ OH⁻] pH = 7 pOH = 7

15. pOH Scale Strong Acids Weak & Dilute Acids Weak & Dilute Bases Strong Base Neutral ⇓ pH + pOH = 14 Chemistry Reference Tables

17. Answers

18. Examples of Acids and Bases

19. pH Scale http://www.johnkyrk.com/pH.html

20. pH & indicators - 4:30 minutes

21. pH indicators What is the approximate pH of the solution tested in the picture? Is the solution an acid or a base? Is it strong or weak?

22. pH Indicators Litmus Paper Phenolphthalein Blue - indicates base Red - indicates acid Litmus (pH indicator)pH indicator below pH 4.5 above pH 8.3 4.5↔8.3 pH below 8 pH 8 - 12pH above 12 ColorlessFuchsiaColorless

23. pH Indicators - different indicators for different purposes Scientist choose indicators based on the solution and process to be monitored.

24. Bromothymol Blue Acid = yellow Neutral = green Base = blue pH range Description Colour <3 Strong acidRed 3-6 AcidOrange/Yellow 7 NeutralGreen 8-11 AlkaliBlue > 11 Strong alkaliViolet/Purple Universal Indicator

25. Strength of Acids and Bases http://ed.ted.com/lessons/the-strengths-and-weaknesses- of-acids-and-bases-george-zaidan-and-charles-morton http://ed.ted.com/lessons/the-strengths-and-weaknesses- of-acids-and-bases-george-zaidan-and-charles-morton 4 minutes Write notes:

26. Strength vs. concentration – start 1:48

27. Concentration⇎ Strength Concentrated or dilute - Molarity 6M vs. 0.6 M Strength or weak = degree to which acids or bases separate into ions

28. Strength vs. Concentration Strength in acids Based on degree H⁺ ions separate from the anion Proportion of acid molecules in which H⁺ separate compared to how many acid molecules do not separate Strong acids = most H⁺ separate Examples: HCl, HNO₃ and H₂SO₄ Weak acids = only some H⁺ separate Examples: HF, HC₂H₃O₂ Strength of Bases Strong = most OH ⁻ separate from the metal

29. Reacting acids and bases HCl (aq) + Na(OH) (aq) → HOH + NaCl Write the word formula Identify the type of chemical reaction What is happening with the reactants and products? Ionic equation: Solubility rules:

30. Neutralization reactions Special double replacement reaction Always: Reactants: Acid + Base (any order) Products: Salt (ionic compound) + Water Practice: sulfuric acid and calcium hydroxide

31. Acid Base Reactions (0 – 2:50 min)

32. Neutralization reactions Acid + Base → Salt + Water sulfuric acid and calcium hydroxide potassium hydroxide and nitric acid carbonic acid and magnesium hydroxide hydrobromic acid and lithium hydroxide

33. Salts formed in the previous problems sulfuric acid and calcium hydroxide salt name:calcium sulfate salt formula: CaSO 4 potassium hydroxide and nitric acid salt name: potassium nitrate salt formula: KNO 3 carbonic acid and magnesium hydroxide salt name: magnesium carbonatesalt formula: MgCO 3 hydrobromic acid and lithium hydroxide salt name:lithium bromide salt formula: LiBr