1. To understand the process of dissolving
Objectives
To understand the process of dissolving
To learn why certain substances dissolve in water and to predict solubility
To learn qualitative terms describing the concentration of a solution
To understand the factors that affect the rate at which a solid dissolves   

2. What is a solution?
Solution – homogeneous mixture
Solvent – substance present in largest amount
Solutes – other substances in the solution
Aqueous solution – solution with water as the solvent

4. Solubility of Ionic Substances
A. Solubility
Solubility of Ionic Substances
Ionic substances breakup into individual cations and anions. PHet Solubility

5. Solubility of Ionic Substances
A. Solubility
Solubility of Ionic Substances
Polar water molecules interact with the positive and negative ions of a salt.

6. Solubility of Polar Substances
A. Solubility
Solubility of Polar Substances

7. Ethanol is soluble in water because of the polar OH bond.
A. Solubility
Ethanol is soluble in water because of the polar OH bond.

8. Why is solid sugar soluble in water?
A. Solubility
Solubility of Polar Substances
Why is solid sugar soluble in water?

9. Substances Insoluble in Water
Nonpolar oil does not interact with polar water.
Water-water hydrogen bonds keep the water from mixing with the nonpolar molecules.

10. How Substances Dissolve
A. Solubility
How Substances Dissolve
A “hole” must be made in the water structure for each solute particle.
The lost water-water interactions must be replaced by water-solute interactions.
“like dissolves like”

11. Predict if the following substances would dissolve in water….
A. Solubility
Predict if the following substances would dissolve in water….
NH3
BCl3
CH4
CH3Cl
H2S
HCl

12. How Substances Dissolve “like dissolves like” Packing popcorn demo
A. Solubility
How Substances Dissolve
“like dissolves like”
Packing popcorn demo
Phenolphthalein in water
What makes a good waterproof material?
Gum in your hair?

13. Predict if the following substances would dissolve in water or oil
A. Solubility
Predict if the following substances would dissolve in water or oil
CH3OH
CH2Cl2
BF3
CH4
CH3CH2CH2CH2OH
CCl4
AsH3
A bear swimming off the coast of Alaska

14. Why does soap do such a great job of dissolving most solutes?
A. Solubility
Why does soap do such a great job of dissolving most solutes?

15. B. Solution Composition: An Introduction
The solubility of a solute is limited.
Saturated solution – contains as much solute as will dissolve at that temperature
Unsaturated solution – has not reached the limit of solute that will dissolve

16. B. Solution Composition: An Introduction
Supersaturated solution – occurs when a solution is saturated at an elevated temperature and then allowed to cool but all of the solid remains dissolved
Contains more dissolved solid than a saturated solution at that temperature
Unstable – adding a crystal causes precipitation
VIDEO? Hand Warmers?

17. B. Solution Composition: An Introduction
Solutions are mixtures.
Amounts of substances can vary in different solutions.
Specify the amounts of solvent and solutes
Qualitative measures of concentration
concentrated – relatively large amount of solute
dilute – relatively small amount of solute

18. B. Solution Composition: An Introduction
Which solution is more concentrated?

19. B. Solution Composition: An Introduction
Now which solution is more concentrated?

20. B. Solution Composition: An Introduction
Now What units are used to express concentration?
amount/volume
mol/L
g/L
mg/L

21. C. Factors Affecting the Rate of Dissolving
Surface area (molecular exposure) (grind)
Stirring (increases molecular interactions)
Temperature (increases speed of molecule)
How will an increase in any of the above 3 factors affect the rate of dissolving? Why?

22. To understand the process of dissolving
Objectives Review
To understand the process of dissolving
To learn why certain substances dissolve in water and to predict solubility
To learn qualitative terms describing the concentration of a solution
To understand the factors that affect the rate at which a solid dissolves  
Work Session: Page 527 # 1, 3, 4, 6

23. To understand mass percent and how to calculate it
Objectives
To understand mass percent and how to calculate it
To understand and use molarity
To learn to calculate the concentration of a solution made by diluting a stock solution

24. A. Solution Composition: Mass Percent

25. A. Solution Composition: Mass Percent
A solution is prepared by mixing 1.0 g of ethanol CH3CH2OH with g of H2O. Calculate the mass percent of ethanol in this solution.
mass % = mass solute X 100
mass solution
mass % = ?
mass solute =
mass solution =

26. A. Solution Composition: Mass Percent
A solution is prepared by mixing 1.0 g of ethanol CH3CH2OH with g of H2O. Calculate the mass percent of ethanol in this solution.
mass % = mass solute X 100
mass solution
mass % = g X 100
100.0 g g
0.990% ethanol

27. A. Solution Composition: Mass Percent
If cow’s milk contains 4.5% by mass of lactose, C12H22O11, calculate the mass of lactose present in 175 g of milk.
mass % = mass solute X 100
mass solution
mass % =
mass solute =
mass solution =

28. A. Solution Composition: Mass Percent
If cow’s milk contains 4.5% by mass of lactose, C12H22O11, calculate the mass of lactose present in 175 g of milk.
mass % = mass solute X 100
mass solution
mass % = 4.5%
mass solute = ?
mass solution = 175 g

29. A. Solution Composition: Mass Percent
If cow’s milk contains 4.5% by mass of lactose, C12H22O11, calculate the mass of lactose present in 175 g of milk.
mass solute= ?
mass solute = mass% (mass solution )
100
mass solute = 4.5% (175 g)
7.9 g lactose

30. B. Solution Composition: Molarity
Concentration of a solution is the amount of solute in a given volume of solution.

31. B. Solution Composition: Molarity
Consider both the amount of solute and the volume to find concentration.

32. B. Solution Composition: Molarity
To find the moles of solute in a given volume of solution of known Molarity use the definition of Molarity.
Molarity = moles of solute
liters of sol’n
Solve for moles of solute?
moles of solute = (Molarity)(liters of sol’n)
Deriving new formulas!!

33. B. Solution Composition: Molarity
Calculate the Molarity of a solution prepared by dissolving 11.5 g of solid NaOH in enough water to make 1.5 L solution.
Molarity = M = moles of solute
L of solution
M =
Moles solute =
L of solution =

34. B. Solution Composition: Molarity
Calculate the Molarity of a solution prepared by dissolving 11.5 g of solid NaOH in enough water to make 1.5 L solution.
Molarity = M = moles of solute
L of solution
M = ?
Moles solute = g =
L of solution = 1.5 L
M = (0.288 mol)/(1.5 L) = M

35. B. Solution Composition: Molarity
Calculate the Molarity of a solution prepared by dissolving 1.56 g of gaseous HCl in enough water to make 26.8 mL solution.
Molarity = M = moles of solute
L of solution
M =
Moles solute =
L of solution =

36. B. Solution Composition: Molarity
Calculate the Molarity of a solution prepared by dissolving 1.56 g of gaseous HCl in enough water to make 26.8 mL solution.
Molarity = M = moles of solute
L of solution
M = ?
Moles solute = g =
L of solution = 26.8 mL =

37. B. Solution Composition: Molarity
Calculate the Molarity of a solution prepared by dissolving 1.56 g of gaseous HCl in enough water to make 26.8 mL solution.
Molarity = M = moles of solute
L of solution
M = ?
Moles solute = mol
L of solution = L
M = ( mol)/( L) = 1.59 M HCl

38. B. Solution Composition: Molarity
To analyze the alcohol content, a chemist needs 1.0 L of 0.20 M K2Cr2O7 solution. What mass of K2Cr2O7 is needed?
M = moles of solute
L of solution
M = solve for ?
Moles solute =
L of solution =

39. B. Solution Composition: Molarity
To analyze the alcohol content, a chemist needs 1.0 L of 0.20 M K2Cr2O7 solution. What mass of K2Cr2O7 is needed?
M = moles of solute
L of solution
M = 0.20 M
moles solute = ?
L of solution = 1.0 L
moles of solute = M(L of solution)

40. B. Solution Composition: Molarity
To analyze the alcohol content, a chemist needs 1.0 L of 0.20 M K2Cr2O7 solution. What mass of K2Cr2O7 is needed?
moles of solute = M(L of solution)
moles of solute = (0.20 M) (1.0 L)
moles of solute = 0.2 mol
Need g??
0.2 mol K2Cr2O = g
294.2 g/mol  58.8 g K2Cr2O7

41. B. Solution Composition: Molarity
Standard solution - a solution whose concentration is accurately known
To make a standard solution
Mass out a sample of solute.
Transfer to a volumetric flask.
Add enough solvent to mark on flask.
Spinner plate, magnetic pill, wand…….

42. B. Solution Composition: Molarity (Glassmaking)

43. C. Dilution
Water can be added to an aqueous solution to dilute the solution to a lower concentration.
Only water is added in the dilution – the amount of solute is the same in both the original and final solution.

44. D. Dilution
Diluting a solution
Mix a measured amount of original solution with DI water in a volumetric flask
Use the formula M1V1 = M2V2
M = Molarity
V = Volume

45. D. Dilution

46. D. Dilution
How much water must be added to 1.0 L of 8.0 M HCl to dilute it to a 5 M solution?
M1V1 = M2V2
M1=
V1 =
M2=
V2 =
V2 = 1.6 L

47. D. Dilution
What volume of 16 M NaOH must be used to prepare 1.5 L of a 0.10 M NaOH solution?
M1V1 = M2V2
M1=
V1 =
M2=
V2 =
V2 = 9.4 X 10-3 L = mL
9.4 mL

48. To understand mass percent and how to calculate it
Objectives Review
To understand mass percent and how to calculate it
To understand and use molarity
To learn to calculate the concentration of a solution made by diluting a stock solution
Why ask a chemist for advice?
Work Session: Review 15.2 page 540 #1, 4, 5, 6, 7: Pg 528 Practice Prob 15.1, Pg 530 PP 15.2, Pg 532 PP 15.4, Pg 535 PP 15.7, Pg 539 PP 15.8

49. To understand the effect of a solute on solution properties
Objectives
To understand the effect of a solute on solution properties   

50. Objectives
To   

52. D. Boiling Point and Freezing Point
The presence of solute “particles” causes the liquid range to become wider.
Boiling point increases
(add a pinch of salt when you boil water for spaghetti)
Freezing point decreases
(add rock salt when you make ice-cream)
Salting the Interstate in winter

53. D. Boiling Point and Freezing Point
Why does the boiling point increase?
Forming a bubble in a solution

54. D. Boiling Point and Freezing Point
Solute particles block some of the water molecules trying to enter the bubble.
Need higher pressure to maintain the bubble because of fewer particles colliding

55. D. Boiling Point and Freezing Point
Colligative property – a solution property that depends on the number of solute particles present
Boiling Point Elevation
Freezing Point Depression

56. To understand the effect of a solute on solution properties
Objectives Review
To understand the effect of a solute on solution properties
Work Session: Review Page 553 #8 Page 557 # 49, 51   

57. This is the end of the required material for this chapter.
Objectives Review
This is the end of the required material for this chapter.  

58. To learn to solve stoichiometric problems involving solution reactions
Objectives Review
To learn to solve stoichiometric problems involving solution reactions
To do calculations involving acid-base reactions
To learn about normality and equivalent weight
To use normality in stoichiometric calculations
To understand the effect of a solute on solution properties   

59. A. Stoichiometry of Solution Reactions

60. B. Neutralization Reactions
An acid-base reaction is called a neutralization reaction.
Steps to solve these problems are the same as before.

61. C. Normality
Unit of concentration
One equivalent of acid – amount of acid that furnishes 1 mol of H+ ions
One equivalent of base – amount of base that furnishes 1 mol of OH ions
Equivalent weight – mass in grams of 1 equivalent of acid or base

62. C. Normality

63. C. Normality

64. C. Normality
To find number of equivalents

65. C. Normality
Advantage of equivalents