1. Chapter 15: Solutions 15.1 Solubility
Objectives: To understand the process of dissolving.
To learn why certain substances dissolve in water.

2. Chapter 15.1: Solutions
Solution: Homogeneous mixture in which the components are uniformly intermingled.
Examples: air, shampoo, orange soda, coffee, gasoline, cough syrup, etccc…
Solvent: substance present in the largest amount.
Solute: the other substance.
Aqueous solution: water as the solvent.

3. Figure 15.1: Dissolving of solid sodium chloride.

4. Figure 15.2: Polar water molecules interacting with positive and negative ions of a salt.

5. Chapter 15.1: Solutions Solubility of Polar Substances:
Can form hydrogen bonds.
Makes it compatible with water.
Water
Ethanol

6. Figure 15.3: The polar water molecule interacts strongly with the polar O—H bond in ethanol.

7. Figure 15.4: Structure of common table sugar.
Contains many polar O-H bonds each of which can
hydrogen-bond to a water molecule.

8. Figure 15.5: A molecule typical of those found in petroleum.
Similar
electronegativity
Share electrons ==
Nonpolar

9. Like dissolves Like
Nonpolar solutes dissolve in nonpolar solvents.

10. 15.2: Solution Composition: An Introduction
Objective: To learn qualitative terms associated with concentration of a solution.

11. 15.2: Solution Composition: An Introduction
Saturated solution: contains as much solute as will dissolve at that temperature.
Unsaturated: solution that has not reached the limit of solute.
Supersaturated solution: contains more dissolved solid than a saturated solution will hold at that temperature. A supersaturated solution is very unstable.
Concentrated solution: relatively large amount of solute
Dilute Solution: small amount of solute.

12. 15.3: Factors Affecting the Rate of Dissolution
Objectives:
1) To understand the factors that affect the rate at which a solute dissolves.

13. 15.3: Factors Affecting the Rate of Dissolution
Three factors affect the speed of the dissolving process.
Surface area
Stirring
Temperature

14. 15.4: Solution Composition: Mass Percent
Objective:
To understand the concentration term mass percent and learn how to calculate it.

15. 15.4: Solution Composition: Mass Percent
Mass percent = mass of solute x 100%
mass of solution
Mass percent = grams of solute x 100%
grams of solute + grams of solvent

16. 15.4: Solution Composition: Mass Percent
A solution is prepared by mixing 2.5 g of calcium chloride w/ 50.0g of water.
Calculate the mass percent of calcium chloride in this solution.
4.76%

17. 15.4: Solution Composition: Mass Percent
A solution is prepared by mixing 1.00 g of ethanol with g of water. Calculate the mass percent of ethanol in this solution.
0.990%

18. 15.4: Solution Composition: Mass Percent
A solution of milk contains 4.5% by mass of lactose. Calculate the mass of lactose present in 175 g of milk.
7.9 g

19. 15.5: Solution Composition: Molarity
Objectives:
To understand molarity.
To learn to use molarity to calculate the number of moles of solute present.

20. 15.5: Solution Composition: Molarity
To measure the concentration by volume.
concentration is defined as the amount of solute in a given volume of solution.
Molarity (M) describes the amount of solute in moles and the volume of the solution in liters.
Molarity is the number of moles of solute per volume of solution in liters.

21. 15.5: Solution Composition: Molarity
Molarity is the number of moles of solute per volume of solution in liters.
M=molarity= moles of solute = mol
liters of solution L

22. 15.5: Solution Composition: Molarity
Calculate the molarity of a solution prepared by dissolving 11.5 g of solid NaOH in enough water to make 1.5L of solution.
0.192 M

23. 15.5: Solution Composition: Molarity
Calculate the molarity of a solution prepared by dissolving 1.56 g of gaseous HCl into enough water to make 26.8 ml
1.59 M

24. 15.5: Solution Composition: Molarity
Give the concentrations of all the ions in each of the following solutions.
0.50 M Co(NO3)2
1 M FeCl3
0.50 M Co, 1.0M NO3
1 M Fe, 3.0 M Cl

25. 15.5: Solution Composition: Molarity
To analyze the alcohol content of a certain wine, a chemist needs 1.00 L of an aqueous M K2Cr2O7. How much solid K2Cr2O7 (molar mass =294.2 g) must be weighed out to make this solution?
0.200 mol, 58.8 g

26. Standard solution: is a solution whose
concentration is accurately known.
Figure 15.7: Steps involved in the preparation of a standard aqueous solution.

27. 15.5: Solution Composition: Molarity
How many moles of Ag+ ions are present in 25 ml of a 0.75 M AgNO3 solution?
0.50 M Co, 1.0M NO3
1 M Fe, 3.0 M Cl

28. 15.6: Dilution
Objective: To learn to calculate the concentration of a solution made by diluting a stock solution.

29. 15.6: Dilution
Objective: To learn to calculate the concentration of a solution made by diluting a stock solution.

30. 15.6: Dilution
Stock solution is purchased. Often need to add water or another solvent to get to the desired concentration.
Moles of solute after dilution=moles of solute before dilution
# of moles of solute stays the same, but more water is added increasing the volume, so the molarity decreases.
M= moles of solute
volume (L)

31. 15.6: Dilution Volume of dilute molarity of moles of solute
Solution (liters) x dilute soln. = present

32. 15.6: Dilution
What volume of 16M sulfuric acid must be used to prepare 1.5 L of a 0.10M H2SO4 solution?
9.4 ml

33. 15.6: Dilution
What volume of 19M sodium hydroxide must be used to prepare 1.0L of a 0.15M NaOH solution?
7.9 ml

34. 15.6: Dilution
What volume of water is needed to prepare ml of a M Ca(NO3)2 solution from a 5.00 M Ca(NO3)2 solution?
475 ml

35. 15.7: Stoichiometry of Solution Reactions
Objectives: To understand the strategy for solving stoichiometric problems for solution reactions

36. 15.7: Stoichiometry of Solution Reactions
Step 1: Write the balanced equation for the reaction. For reactions involving ion, it is best to write the net ionic equation.
Step 2: Calculate the moles of reactants.
Step 3: Determine which reactant is limiting.
Step 4: Calculate the moles of other reactants or products, as required.
Step 5: Convert to grams or other units, if required.

37. 15.7: Stoichiometry of Solution Reactions
Calculate the mass of solid NaCl that must be added to 1.50 L of a M AgNO3 solution to precipitate all of the Ag+ ions in the form of AgCl. Calculate the mass of AgCl formed.
21.5 g AgCl

38. 15.7: Stoichiometry of Solution Reactions
Calculate the mass of solid sodium sulfate that must be added to ml of a 0.2 M solution of barium nitrate to precipitate all of the barium ions in the form of barium sulfate. Also calculate the mass of barium sulfate forms.
7.10 g Na2SO4; 11.7 g BaSO4

39. 15.7: Stoichiometry of Solution Reactions
Calculate the mass of sodium iodide that must be added to ml of a M Pb(NO3)2 solution to precipitate all of the Pb2+ ions as PbI2. Also calculate the mass of PbI2 forms.
12.7 g NaI; 19.6g PbI2

40. 15.7: Stoichiometry of Solution Reactions
Calculate the mass of the white solid CaCO3 that forms when 25.0 ml of a M Ca(NO3)2 solution is mixed with 20.0 ml of a 0.150M Na2CO3 solution.
0.250 g CaCO3

41. 15.7: Stoichiometry of Solution Reactions
Calculate the mass of the blood-red solid Ag2CrO4 that forms when 50.0 ml of a 0.250M AgNO3 solution is mixed with 30.0 ml of a 0.250M K2CrO4 solution.
2.07 g Ag2CrO4

42. 15.8: Neutralization Reactions
Objective: To learn how to do calculations involved in acid-base reactions.
Neutralization reaction: acid-base reaction
When just enough strong acid is added to
react exactly with the strong base, the
acid is neutralized. One product is water.

43. 15.8: Neutralization Reactions
What volume of a M HCl solution is needed to neutralize 25.0 ml of a M NaOH solution?
8.75 x 10-2 L

44. 15.8: Neutralization Reactions
What volume of a M HNO3 solution is needed to neutralize 45.0 ml of a M KOH solution?
165 ml

45. 15.8: Neutralization Reactions
What volume of a 1.00 x 10-2 M HCl solution is needed to neutralize 35.0 ml of a 5.00 x 10-3 M Ba(OH)2 solution?
35.0 ml

46. 15.9: Normality
Objectives: To learn about normality and equivalent weight.
To learn to use these concepts in stoichiometric calculations.

47. 15.9: Normality Normality:
Equivalent of an acid: amt. of acid that can furnish 1 mol of H+ ions.
Equivalent of a base: amt of base that can furnish 1 mol of OH- ions.
Equivalent weight: mass in grams of 1 equivalent of that acid or base.

48. 15.9: Normality
Normality: is defined as the number of equivalents of solute per liter of solution.
Normality=N= # of equivalents= equivalents
1 liter of soln. L
Molar Mass Equivalent Wt (g)
HCl g g
H2SO g
H3PO g

49. 15.9: Normality
A solution of sulfuric acid contains 86 g of H2SO4 per liter of solultion. Calculate the normality of this solution.
1.8 N H2SO4

50. 15.9: Normality
Arsenic acid, H3AsO4, can furnish three H+ ions per molecule. Calculate the equivalent weight of H3AsO4.
47.31 g

51. 15.9: Normality
Calculate the equivalent weight of HBr.
80.91 g

52. 15.9: Normality
A solution of phosphoric acid contains 50.0g of H3PO4 per liter of solution. Calculate the normality of this solution.
1.53 N

53. 15.9: Normality
A solution of hydrochloric acid contains 25.0 g of HCl per liter of solution. Calculate the normality of this solution.
0.686N

54. 15.10: The Properties of Solutions: Boiling Point and Freezing Point
Objective: To understand the effect of a solute on solution properties.
1.0M NaCl solution freezes at about -1oC.
Boils at 104oC.

55. Figure 15.9: A bubble in the interior of liquid water surrounded by solute particles and water molecules.

56. Figure 15.10: Pure water. Colligative property: depends on the number
of solute particles.