1. Solutions and Solubility
Chapters 15 and 16

2. Solution Homogeneous Mixture Aqueous Solution Uniform Throughout
Something mixed in water
NaCl(aq)

3. Solution Components Solvent Solute Dissolving medium in mixture
Dissolved particles in solution

4. Solubility
measure of the amount of solute that can dissolve in a given quantity of solvent at certain conditions
How much can dissolve

5. Solubility Soluble Insoluble Solute will dissolve in solvent
Solute will not dissolve in solvent

6. Factors that affect Solubility
Temperature
Pressure
Type of Chemical

7. Temperature
increasing temperature increases solubility of solids and liquids in other solids and liquids
decreasing temperature increases solubility of gases in liquids
Ex: Cold soda is fizzy

8. Pressure
Increasing partial pressure of gas above liquid increases solubility of the gas in the liquid
Example
Soda Bottles

9. Type of Chemical “Like dissolves Like”
Polar and ionic substances will dissolve in polar solvents
Nonpolar substances will dissolve in nonpolar solvents

11. Solutions Concentrated Dilute
General term for a lot of solute dissolved in solvent
Dilute
General term for not a lot of solute dissolved in solvent
Opposite of concentrated

12. Table G
Shows the relationship between temperature and amount of solute for a number of different compounds

13. Table G
How much NaNO3 can dissolve in 100g of H2O at 50°C?
115g

14. Table G At what temperature can 60g of NH4Cl dissolve in 100g of H2O?

16. Types of Solution Saturated Unsaturated Supersaturated
maximum amount of solute for a given quantity of solvent
At Equilibrium
Unsaturated
contains less than the maximum amount of solute
Supersaturated
Contains more solute than it can theoretically hold

17. Supersaturated Solutions
Begins as saturated solution at high temp
As solution cools, with no disturbance, solubility decreases
Any disturbance, or place for a crystal to grow, will cause any excess solute to precipitate out back to a saturated solution

18. Solution Types Saturated Unsaturated Supersaturated On the line
Under the line
Supersaturated
Above the line

20. Electrolytes
Compounds that conduct an electrical current when melted or dissolved
Ionic compounds
Including acids and bases
NaCl, KNO3, HCl

21. Dissolving vs. Dissociation
Molecules separate as solvent molecules mix
C6H12O6(s) + H2O(l)  C6H12O6(aq)
Dissociation
Ions separate as solvent molecules mix
NaCl(s) + H2O(l)  Na+(aq) + Cl-(aq)

22. Dissociation Simulation

24. Concentration
Quantitative measure of the amount of solute dissolved in a given quantity of solvent
Molarity
Percent Composition
by mass, by volume
Parts Per Million (ppm)

25. Molarity Molarity = Moles of Solute Liters of Solution 1 mol/L = 1 M
Often used for solids dissolved into liquids
Most common concentration system

26. Molarity Example
What is the molarity of 2 moles of glucose dissolved in 5 Liters of solution?
Molarity = Moles of Solute Liters of Solution

27. Example
How many moles of HCl are dissolved in 4L of a 3M solution of HCl?
Molarity = Moles of Solute Liters of Solution

28. Example What volume of a 6M solution contains 0.6moles of NaCl?
Molarity = Moles of Solute Liters of Solution

30. Percent Composition Percent Comp = Part x 100% Whole By mass %(m/m)
Usually used for solid - solid solutions
By Volume %(v/v)
Usually used for liquid - liquid solutions

31. (v/v) Example
A solution contains 60 mL of NH3 in a 1 Liter solution, what is the percent by volume composition of this solution?

33. Parts Per Million (ppm)
Used for very small concentrations
ppm = grams of solute x 1,000, grams of solution
Units = ppm

34. ppm example
A 2 kg bar of silver contains 0.05 g of gold, what is the parts per million concentration of gold in the silver bar?
25 ppm Au

35. Example
A bar of tantalum has a niobium concentration of 16ppm. How much does the bar weigh if the niobium weighs 0.004g?

37. Colligative Properties of Solutions
Properties of a solution that depend only on the number of particles dissolved
Vapor Pressure
Boiling Point
Melting Point

38. Vapor Pressure
Pressure exerted by a vapor that has evaporated and is still above a liquid
More solute particles get in the way of solvent particles trying to evaporate
Adding more nonvolatile solute particles to pure solvent decreases vapor pressure

39. Boiling Point
Temperature at which a liquid boils at a given pressure, related to vapor pressure.
More solute particles get in the way of solvent particles trying to escape liquid phase
Adding more solute particles to pure solvent increases boiling point

40. Freezing Point
Temperature at which a liquid freezes, or the particles line up in an orderly pattern.
More solute particles get in the way of the solvent particles trying to line up.
Adding more solute particles to pure solvent decreases freezing point

41. Number of Particles
When a covalent compound dissolves the compound stays intact.
When an ionic compound dissociates the compound splits into its ions.

42. Examples
When glucose, C6H12O6, dissolves it will split into how many particles?
1, C6H12O6
When NaCl dissociates it will split into how many particles?
2, Na+ and Cl-
When CaCl2 dissociates it will split into how many particles?
3, Ca2+, Cl-, and Cl-

43. Example For a solution of each glucose, NaCl, and CaCl2 Substance
calculation
Change in Temp
Glucose
(4M)(1particle) 4
NaCl
(3M)(2particles) 6
CaCl2
(1M)(3particles) 3

44. Real Life Why do we put salt on roads in winter?
Salt lowers freezing point, ice melts
Which is better NaCl or CaCl2?
CaCl2, more particles
Why do some people use salt when cooking pasta? (Besides Taste)
Raises boiling point, cooks at higher temperature