1. Water Dissolving Salt

2. Solubility & Saturation FILL IN HANDOUT AS WE GO…

3. Solubility Solubility: maximum amount of solute that can be dissolved in a given quantity of solvent at a specific temperature. Even for very soluble substances, there’s a limit to how much can be dissolved in a given amount of solvent.

4. Saturation Saturated solution: solution at the limit ◦Solution has as much solute as it can dissolve at that T (temperature) ◦If more solute is added it won’t dissolve and will only precipitate out ◦In a state of dynamic equilibrium: rate of dissolving = rate of crystallizing

5. Saturation Unsaturated solution: solution under the limit ◦Solution hasn’t reached the limit of how much solute it can dissolve at that T ◦If more solute is added it will dissolve Supersaturated solution: solution above the limit ◦Solution contains higher than saturation concentration of solute ◦Any slight disturbance/seeding causes crystallization/precipitation of excess solute

6. Supersaturation – needle structure Supersaturation – seeding

7. Ex: At 20 ⁰ C, solubility of NaCl (s) in water is 36g/100mL.

8. Saturation Concentration ([ ]): quantitative measure (a number) of how much solute is contained in an amount of solvent. ◦Ex:

9. Saturation Concentrated solution: qualitative term; “large” amount of solute dissolved. Dilute solution: qualitative term; “small” amount of solute dissolved.

10. Q: At 20 ⁰ C, KCl (s) solubility is 34g/100g of water. In the laboratory, a student mixes 45g KCl (s) with 100g of water at 20 ⁰ C. A.How much KCl (s) will dissolve? ___________ B.Is the solution saturated? ___________ C.What is the mass in grams of solid KCl that won’t dissolve? __________________________

11. Q: At 50 ⁰ C, the solubility of NaNO 3(s) is 114g/100g of water. How many grams of NaNO 3(s) are needed to make a saturated solution of 50g of water at 50 ⁰ C?

12. Practice! Practice: p. 223 # 4-10, p. 226 #1-7, 9, 10 Read: p. 220-226

13. Flame Tests

14. Concentration NOT THE TYPE YOU NEED FOR A TEST

15. Concentration Concentration: quantitative measure of solute in solvent. How much solute is dissolved in solvent. Can be represented by different units, ∴ there are different ways of stating concentration. Most commonly used: molar concentration or molarity = _________ = C C =

16. Ex 1: What is the molar concentration of 4.00L solution with 1.54mol NaOH in it?

17. Ex 2: What is the molarity of 0.23mol of sodium sulphate dissolved in 500mL of water?

18. Ex 3: 4.00g of NaOH is dissolved in 250mL of solution. What’s the molarity of NaOH (aq) ?

19. Ex 4: How many mL of 0.400M NaOH solution will contain 1.00g of NaOH?

20. Ex 5: How many moles are in 2.00L of 4.00mol/L solution of NaCl?

21. Ex 6: What is the mass of NaCl in the previous example?

22. Ex 7: What’s the volume when 0.500 moles of NaOH make a 3.00mol/L solution?

23. Ex 8: Calculate the mass of Na2CO3 required to make 3.5L of a 1.2mol/L solution.

24. Ex 9: What volume of 0.500M solution can be made from 12.00g of NaCl?

25. Ex 10: What’s the concentration of a solution with 53.2g of CaCl2 in 5000mL of water?

26. Other Concentration Calculations (% mass, % volume, ppm) Percent by mass: Percent by volume:

27. Ex: What’s the % by mass of NaCl if 9.0g of NaCl is added to 91.0g of water?

28. Ex: What’s the % by volume of ethanol if 15.0mL of ethanol is added to 85.0g of water?

29. Parts per Million (ppm) Parts per million (ppm): same units top and bottom multiplied by a million (10 6 ) ◦Useful for very low concentrations

30. Ex: What is the ppm (m/v) of NaCl if 5.9mg of NaCl is dissolved in 500mL of water?

31. Concentration of Ions in Solution 1. Write a balanced dissociation equation or ionization equation: Ex: Al 2 (SO 4 ) 3(aq) 2. Use the mole ratio and the Factor-Label Method to find the concentration of the ions: Ex: 1.00M Al 2 (SO 4 ) 3(aq). Find [Al 3+ ] and [SO 4 2- ].

33. Ex: A barium hydroxide solution is 2.00mol/L. Find [Ba 2+ ] and [OH - ].

34. Practice! Practice: p. 316 #1-4, 6, p. 214 #2-12, 15 Read: p. 314-215, p. 203-213

35. Strengths/Weaknesses of Acids/Bases

36. Bronsted-Lowry A/B Ionization/Dissociatio n Equations FILL IN THE HANDOUT AS WE GO…

37. How to write equations for ACIDS: General Equation: HA donates H + (proton) to H 2 O (acts as a base):

38. How to write equations for ACIDS: Therefore, a conjugate acid-base pair consists of two substances related to each other by donating/accepting a proton (H+). Ex:

39. How to write equations for ACIDS: The hydronium ion (H 3 O + ) forms from attraction between H + and polar H 2 O. Both H 3 O + and H + are used to measure the strength of an acid (they are used interchangeably).

40. Practice: Identify the conjugate acid- base pairs in the following equations: 1. 2.

41. Practice: Identify the conjugate acid- base pairs in the following equations: 3. 4.

42. Practice: Identify the conjugate acid- base pairs in the following equations: 5. 6.

43. Polyprotic Acids! The last 3 equations are examples of polyprotic acids! ◦Polyprotic acids can lose more than one proton (H + ): ◦Ex: So they can react with H 2 O more than once to produce many H 3 O + ! ◦# times an acid can react = # H’s at the front; each time it reacts, it gets weaker

44. Favouring Stronger Products In all of the above equations, the products are stronger acids and bases than the reactants. Remember: strong acids completely ionize. Weaker acids don’t and we can represent this with a forward and reverse arrow. Ex:

45. How to write equations for BASES: 1. If it has an OH - (hydroxide): simply write the dissociation equation ◦General Equation: (these are strong bases!) Ex: NaOH (aq)

46. How to write equations for BASES: 2. If it has no OH- (hydroxide): split the cmpd into its ions and use the anion (-ve one). ◦React the anion with H 2 O to produce OH - ◦Determine the other product (it’s the anion gaining a H + ). Remember: acids lose H +, bases gain H + ◦General Equation: (these are weak bases!)

47. Ex: Na 2 CO 3

48. Ex: Na 3 PO 4

49. Ex: NH 3

50. Polyprotic Bases Polyprotic bases: can accept more than one proton (H + ) so it can react with H 2 O many times to produce many OH - (hydroxide ions): ◦Ex: # times it can react = # charge

51. Strong vs. Weak Acids/Bases: The stronger the acid, the more H 3 O + it produces, the higher its [H3O+], and the more forward the ionization moves (>99% ionization): ◦General Equation: ◦(There are 7 strong acids and they’re listed on the data sheet)

52. Strong vs. Weak Acids/Bases: The stronger the base, the more OH - it produces, the higher its [OH - ], and the more forward the dissociation moves (>99% dissociation): ◦General Equation: ◦(Strong bases: have OH- and a Group 1 metal/Alkali metal)

53. Strong vs. Weak Acids/Bases: Weak acids and bases only partially ionize and dissociate (<50%): ◦General Equation:

54. Strong vs. Weak Acids/Bases: So the reverse process dominates over the forward process:

55. Strong vs. Weak Acids/Bases: ◦General Equation (weak acid): ◦General Equation (weak base):

56. Dissociation of strong/weak acids

57. pH Scale Practice! FILL IN THE HANDOUT AS WE GO…

58. 1. How many significant digits/figures are there? a) pH = 10.01 __________ sig figs b) pH = 7.3 __________ sig figs c) 0.0034mol/L __________ sig figs d) 5.60 x 10 -10 M __________ sig figs

59. 2. What’s the pH? Formula: a)Hydronium ion concentration of 5.1 x 10 -6 mol/L? pH = __________ b)[H+] = 1.32x10 -3 M pH = __________ c)[H3O+] = 3.05x10 -6 mol/L pH = __________ d)[H+] = 1.7x10 -8 M pH = ___________ e)[H3O+] = 4.500x10 -7 mol/L pH = ___________ f)[H+] = 2.6x10 -12 M pH =____________

60. 3. What’s the [H 3 O + ]? Formula: a)pH = 0.89 [H 3 O + ] = ______________________ b)pH = 5.3 [H 3 O + ] = _______________________ c)pH = 1.370 [H 3 O + ] = _____________________ d)pH = 9.00 [H 3 O + ] = ______________________ e)pH = 13.014 [H 3 O + ] = ____________________

61. 4. pH of 0.152M HBr (aq) ?

62. 5. pOH of 3.5x10 -4 M HCl (aq) ?

63. 6. pOH of 0.040M H 2 SO 4(aq) ?

64. 7. pOH, [H + ] and pH of 0.100M NaOH (aq) ?

65. 8. Calculate [H + ] and pH of 0.002M Ca(OH) 2(aq).

66. 9. Calculate [H + ] and pH of 8.5x10 -5 M LiOH (aq).

67. HCl & NaOH rxn with Universal Indicator