1. Solutions 1

2. The colors of soap bubbles depend on the thickness of their walls.
Source: Graeme Richard White

3. The Solution Process Covalent Molecules
Covalent molecules that are small and have “polar” groups tend to be soluble in water
The ability to H-bond with water enhances solubility O H C 4

4. Solubility
When one substance (solute) dissolves in another (solvent) it is said to be soluble
Salt is soluble in Water,
Bromine is soluble in methylene chloride
When one substance does not dissolve in another they are said to be insoluble
Oil is insoluble in Water
There is usually a limit to the solubility of one substance in another
Gases are always soluble in each other
Some liquids are always mutually soluble 5

5. Solutions & Solubility
Molecules that are similar in structure tend to form solutions
Like dissolves like
The solubility of the solute in the solvent depends on the temperature
Higher Temp = Larger solubility of solid in liquid
Lower Temp =Larger solubility of gas in liquid
The solubility of gases depends on the pressure
Higher pressure = Larger solubility 6

6. Figure 14.3: (a) The ethanol molecule contains a polar O—H bond similar to those in the water molecule. (b) The polar water molecule interacts strongly with the polar O—H bond in ethanol.

7. Figure 14. 5: A molecule typical of those found in petroleum
Figure 14.5: A molecule typical of those found in petroleum. The bonds are not polar.

8. The drycleaning agent PERC is a health concern for workers in the drycleaning industry.
Source:
Michael Newman/PhotoEdit

9. Figure 14.6: An oil layer floating on water.

10. Describing Solutions - Qualitatively
A concentrated solution has a high proportion of solute to solution
A dilute solution has a low proportion of solute to solution
A saturated solution has the maximum amount of solute that will dissolve in the solvent
Depends on temp
An unsaturated solution has less than the saturation limit
A supersaturated solution has more than the saturation limit
Unstable 7

11. A solution of cobalt (II) nitrate.
Source:
Tom Pantages

12. Describing Solutions Quantitatively
Solutions have variable composition
To describe a solution accurately, you need to describe the components and their relative amounts
Concentration = amount of solute in a given amount of solution
Occasionally amount of solvent 8

13. Solution Concentration Percentage
Parts Per Hundred
% = grams of solute per 100 g of solution
Mass Percent or Percent by Mass
5.0% NaCl has 5.0 g of NaCl in every 100 g of solution
Mass of Solution = Mass of Solute + Mass of Solvent
Divide the mass of solute by the mass of solution and multiply by 100% 9

14. What is the percent by mass of CaCl2 solution if 2
What is the percent by mass of CaCl2 solution if 2.50 grams is added to 50.0 g of water

15. Solution Concentration Molarity
moles of solute per 1 liter of solution
used because it describes how many molecules of solute in each liter of solution
If a sugar solution concentration is 2.0 M , 1 liter of solution contains 2.0 moles of sugar, 2 liters = 4.0 moles sugar, 0.5 liters = 1.0 mole sugar, etc.
molarity =
moles of solute
liters of solution 10

16. What is the molarity of a solution made by dissolving 25 grams of NaCl in 500. mL of water

17. Molarity & Dissociation
the molarity of the ionic compound allows you to determine the molarity of the dissolved ions
CaCl2(aq) = Ca+2(aq) + 2 Cl-1(aq)‏
What is the concentration of Ca+2 and Cl-1 ions in a M solution of CaCl2. 11

18. Dilution
Dilution is adding solvent to decrease the concentration of a solution
The amount of solute stays the same, but the concentration decreases
Dilution Formula
M1 x V1 = M2x V2
Concentrations and Volumes can be most units as long as consistent 12

19. Figure 14.7: Steps involved in the preparation of a standard aqueous solution.

20. Figure 14.8: (a) 28.6 mL of 17.5 M acetic acid solution is transferred to a volumetric flask that already contains some water. (b) Water is added to the flask (with swirling) to bring the volume to the calibration mark, and the solution is mixed by inverting the flask several times. (c) The resulting solution is 1.00 M acetic acid.

21. Approximate dilutions can be carried out using a calibrated beaker
Approximate dilutions can be carried out using a calibrated beaker. Here concentrated sulfuric acid is being added to water to make a dilute solution.
Source:
Tom Pantages

22. When aqueous sodium chloride is added to a solution of silver nitrate, a white silver chloride precipitate forms.

23. Solution Stoichiometry
Many reactions occur in solution, therefore you need to be able to predict amounts of reactants and products in terms of concentrations and volumes as well as masses
Basic strategy is the same
Balance the Equation
Change Given Amounts to Moles
Determine Limiting Reactant
Calculate Moles of Required Substance
Convert Moles of the Required Substance into the Desired Unit 13

24. Example Calculate the Mass of Solid NaCl required to
Precipitate all the Ag+1 ions from 1.50 L of a
0.100 M AgNO3 Solution 14

25. Neutralization Reactions
Acid-Base reactions are also called Neutralization Reactions
Often we use neutralization reactions to determine the concentration of an unknown acid or base
The procedure is called a titration. With this procedure we can add just enough acid solution to neutralize a known volume of a base solution
Or visa versa 18

26. Solution Formation Solutions are homogeneous
mixtures that may be solid, liquid,
or gaseous.
Properties of solutions change
when the number of particles
dissolved in them is changed.

27. The Solution Process - Ionic Compounds
When ionic compounds dissolve in water they dissociate into ions
ions become surrounded by water molecules - hydrated
When solute particles are surrounded by solvent molecules we say they are solvated 3

28. Figure 14.1: When solid sodium chloride dissolves, the ions are dispersed randomly throughout the solution.

29. Figure 14.2: Polar water molecules interact with the positive and negative ions of a salt.

30. Stirring(agitation): speeds up the rate that a crystal will dissolve because the dissolving process is a surface phenomenon.
Temperature:Increase the rate at which solutes dissolve because the kinetic energy of the solute is greater at higher temperature
Particle Size: a fine powder dissolves quicker than larger crystals because finer particles expose a greater surface area to the colliding water molecules.

31. Solubility
Solubility: is the amount that dissolves in a given quantity of a solvent at a given temperature to produce a saturated solution.

32. Solubility
A solution that contains less solute than a saturated solution is unsaturated.
A solution that can dissolve no more solute is saturated.
Two liquids are miscible if they dissolve in each other.
Liquids that are insoluble in each other are immiscible.

33. Factors Affecting Solubility
The solubility of most solid substances increase as the temperature of the solvent increases.
Gas solubility increases as the partial pressure of the gas above the solution increases.

34. Factors Affecting Solubility
Henrys Law:at a given temperature the
solubility (S) of a gas in a liquid is
directly proportional to the pressure(p)
of the gas above the liquid
S1 = S2
P P2
Supersaturated solution : a solution that contains more solute than it should theoretically can continue to hold at a given temperature.

35. Molarity
Molarity is the number of moles of a solute dissolved per liter of solution.
Molarity = Moles of solute
Liters of solution
The concentration of a solution is a measure of the amount of solute that is dissolved in a given quantity of solvent.

36. Molarity
Dilute solution is one that contains only a low concentration of solute.
Concentrated solution contains a high concentration of solute.

37. Boiling-Point Elevation
The boiling point elevation: the difference in temperature between the boiling point of a solution and that of the pure solvent.
The boiling point of a substance is the temperature at which the vapor pressure of the liquid phase equals the atmospheric pressure.

38. Boiling-Point Elevation
Attractive forces exist between the solvent and solute particles.
The presence of a solute raises the boiling point in the solvent.
Boiling point elevation is a colligative property, it depends on the concentration of particles, not their identity

39. Freezing-Point Depression
The freezing-point depression: the difference in temperature between the freezing point of a solution and that of the pure solvent. (freezing-point depression is also a colligative property)‏

40. Freezing-Point Depression
When a substance freezes, the particles of the solid take on a pattern. The presence of a solute in water disrupts the formation of this pattern because of the shells of water of solvation.

41. Molality m = moles of solute / kg of solvent
Molality relates the physical nature of the solute to the solvent
Molality is used to describe “colligative properties and depends on the number of particles, not their identity
NaCl breaks into 2 particles in water Na+ and Cl-, so 1 mole of NaCl is actually 2 moles of particles

42. Thermal Pollution Temp changes the Solubility in a liquid
Gas in a liquid  O2 dissolved in water  relate to “thermal pollution”
Temp changes the Solubility in a liquid
Ecosystem:
O2 decreases, Fish population decreases, Algae increase
-Oxygen dissolves into water because gas is the solute
-Decrease the temp of water, it will dissolve faster
-Decrease the rate of dissolving and Oxygen goes down

43. Reducing Thermal Pollution

45. Colligative Properties
These are the properties of a solvent that depend on the total concentration of solute particles present. They include:
Boiling Point Elevation
Freezing Point Depression
Vapor Pressure Depression
Osmotic Pressure

46. Phase Diagrams –describe the various states of matter at specific temperatures and pressures
Phase Diagram of Water
TRIPLE POINT:
The pressure and temperature at which
all three phases are stable.

47. Phase Diagram of Carbon Dioxide