SCH4U Unit #2: EQUILIBRIUM

1. SCH4UUnit #2: EQUILIBRIUM Ms. Cornacchione Mon Mar 24th2014

2. Unit #2: Acid/Base EquilibriumTOPICS • Bronsted Lowry Acids & Bases (8.1) • Strong and Weak Acids & Bases (8.2) • Acid Calculations (8.4) • Base Calculations (8.5) • Acid-Base Properties of Salts • Acid-Base Titration • Buffer Systems

3. Base Calculations • Strong bases (ionize completely) pH + pOH = 14 • Weak bases (ionize partially) • Must consider EQM and Kb, to calculate pOH

4. EXAMPLES – Calc [H+], [OH-] for Strong Base

5. EXAMPLES – pH for a Strong Base

6. EXAMPLES– pH for Weak Base

7. Unit #2: Acid/Base EquilibriumTOPICS • Bronsted Lowry Acids & Bases • Strong and Weak Acids & Bases • Acid Calculations • Base Calculations • Acid-Base Properties of Salts • Acid-Base Titration • Buffer Systems

8. Acid-Base Properties of Salt Solutions • Many salts are highly soluble in water and easily dissociate into ions that may or may not change the pH of the solution (acidic, basic, or neutral) • We must consider how well each ion acts as an acid or a base (the stronger one wins!)

9. Acid-Base Properties of Salts

10. Salts That Produce Neutral Solutions

11. Salts That Produce Basic Solutions

12. Salts That ProduceAcidicSolutions

13. Acid-Base Properties of Salts

14. Hydrolysis of Amphiprotic Ions

15. Hydrolysis of Metallic and Non-metallic Oxides • Metallic • Non-metallic

16. EXAMPLE

17. EXAMPLE

18. EXAMPLE – Acidity of a Metallic Oxide Solution

20. Practice Makes Perfect • Complete all Section 8.6 Practice Problems • Do Page 539 Q#2-5

21. SCH4UUnit #2: Acid-Base EQM(Titrations) Ms. Cornacchione Mon Mar 24th 2014

22. Unit #2: Acid/Base EquilibriumTOPICS • Bronsted Lowry Acids & Bases • Strong and Weak Acids & Bases • Acid Calculations • Base Calculations • Acid-Base Properties of Salts • Acid-Base Titration • Buffer Systems

23. Titration Introduction • Titration is the chemical analysis involving the addition of known volume & concentration of titrantto a known volume but known concentration of sample • Acid-Base titration – reaction between an acid and base resulting in water and salt (neutralization) • An indicator is used to determine the endpointof the reaction • At the end point, the indicator will change colour

24. Titration Introduction • The equivalence point, or stoichiometric point, occurs when equal moles of H+ and OH- ions have been reacted to produce water • The equivalence point is not always equal to the end point and does not always occur at a pH of 7 • When choosing an indicator for titration, choose an indicator that will change when the equivalence point is reached

25. Titration Introduction

26. Titration Terminology • Standard Solution • Titrant • Equivalence Point • End Point • pH Curve

27. Titration Introduction

28. Titrating Strong Acid with Strong Base • Equivalence point will occur at a pH of 7 • Use an indicator that will change around 7 • Calculations – simple limiting factor problem since there is 100% ionization

29. Titrating Strong Acid with StrongBase (and vice versa)

30. Titrating a Strong Acid with a Strong Base Go to Page 541 • Stage 1 – Before titrant added • Stage 2 - After some titrant added (10mL) • Stage 3 – More titrant (50mL) • Stage 4 – After 100mL Titrant – EQUIV POINT • Stage 5 – After 150mL Titrant

31. Titrating a Strong Acid with a Strong Base

32. Titrating a Strong Acid with a Strong Base

33. Titrating a Weak Acid with a Strong Base • Equivalence point will occur at pH > 7 • Use an indicator that will change above 7 • Calculations – Use an ICE Table! (must consider the equilibrium of the weak acid)

34. Titrating a Strong acid with a Weak Base • Equivalence point will occur at pH < 7 • Use an indicator that will change below 7 • Calculations – Use an ICE Table! (must consider the equilibrium of the weak base)

36. Practice Makes Perfect! • Complete Practice Problem Pg 547 #1-2