1. Ch 14- Solutions

2. Mixtures
Mixture: blend of 2 or more kinds of matter, each retaining its own properties
Heterogeneous
Not uniform in composition
Ex) Vegetable Soup, chocolate chip cookies
Homogeneous
Uniform in composition
Salt Water
Solutions

3. Matter
Pure substance
Element
Compound
Mixture
Homogeneous
solutions
colloid
Heterogeneous

4. Suspensions
Suspension: Particles of a solute are so large that they settle out unless they are mixed or agitated (heterogeneous)
Example: Clay in Water, Muddy Water

5. Colloids
Colloids: Particles of intermediate size between solutions and suspensions (heterogenous)
Cant see through them
Examples:

6. Used to distinguish between solutions and colloids
Tyndall Effect
Used to distinguish between solutions and colloids
Light is scattered when shone through a colloid

7. Solution
A homogeneous mixture of two or more substances, the composition of which may vary.
Examples:
- Kool-Aid
Salt water
Soda

8. Solutions Solute – the substance that is dissolved
Solvent - the substance which dissolves the solute and is normally present in excess
In salt water, salt is the solute and water is the solvent

9. Types of Solutions Gaseous solutions- Two or more gases are mixed.
Example: Air (oxygen in nitrogen)

10. Liquid Solutions
Liquid solutions- Solutions which have a liquid solvent and either a gas, liquid or solid as the solute.
Aqueous solutions- water is the solvent
Solute Solvent Example
gas liquid Seltzer
liquid liquid antifreeze
solid liquid salt water

11. Types of Solutions
Solid solutions- Solutions which have a solid solvent and either a gas, liquid, or solid solute.
Solute Solvent Example
gas solid charcoal filter
liquid solid dental filling
solid solid copper in silver

12. Alloys
Alloys are solutions of two or more metals mixed evenly (homogenous)
Ex- steel, bronze, brass, sterling silver

13. Miscible vs. Immiscible
A miscible pair of substances can be mixed together in any proportion to form a solution.
An immiscible pair of substances cannot be mixed together to form a solution. Example: Oil and water are immiscible.

14. Solubility
Solubility - amount of solute that will dissolve in a given amount of solvent

15. Concentration Dilute – small amount of solute in the solution
Concentrated – large amount of solute in the solution

16. Factors affecting solubility for solids dissolved in a liquid (sugar water):
Temperature – as temp. increases, solubility increases
Surface area – increased surface area increases solubility (crush the solid)
Stirring – increased stirring increases solubility
Pressure – has no effect on solubility

17. Factors affecting solubility of gases dissolved in a liquid
Temperature – as temp. increases, solubility decreases
Surface area – has no effect on solubility
Stirring – increased stirring decreases solubility
Pressure – increased pressure increases solubility

18. Concentrations
Unsaturated- A solution that has less than the maximum amount of solute that can be dissolved.
Saturated- A solution that contains as much solute that can be dissolved under existing conditions of temperature and pressure.
Supersaturated- A solution that contains more than the maximum solute which can be dissolved.

19. The process of solvation
Water molecules, being polar and in constant motion, knock off and attract ions from any ionic solid. Then they surround the ion and act to prevent it from re-attaching to the ionic crystal.

20. Solution equilibrium
Eventually the water becomes so full of ions that it can no longer prevent some ions from re-attaching to the parent crystal. We call this a saturated solution and the solution is said to be in equilibrium.

21. https://www.youtube.com/watch?v=EBfGcTA JF4o

22. Solubility curve diagrams
For most solids solubility in a liquid increases as temp increases.
For most gases solubility in a liquid decreases as temperature increases.

23. What is the solubility of Sodium Acetate, CH3CO2Na, at 60 oC?
Which substance is least soluble at 20 C?
How many grams of potassium bromide can be dissolved in 200ml of water at 60 C?
At 20 C, 80g of sodium nitrate is dissolved in 100ml of water. Is this solution unsaturated, saturated, or supersaturated?
Is 60 grams of sodium acetate in 50 mL of water at 60 oC saturated, unsaturated, or supersaturated?

24. A saturated solution of potassium bromide is formed from 100ml of water. If the saturated solution is cooled from 80 C to 40 C, how many grams of precipitate are formed?

25. You can dissolve gases into water?
Sure, fish don’t breath water they breath oxygen just like you and I. Where is the oxygen? It is dissolved in the water.
- thermal pollution
Consider a can of soda. Open the can and it fizzes from dissolved carbon dioxide leaving solution.

26. Electrolytes vs Nonelectrolyte
Electrolyte = a substance that dissolves in water to give an electrically conducting solution.
Ionic solids and acids dissolved in water - ex: salt water
Nonelectrolyte = a substance that dissolves in water to give a nonconducting or very poorly conducting solution.
Molecular (covalent bond) compounds – ex: sugar water

27. Dissociation
When an ionic compound dissolves in water, the ions separate from each other (cations and anions)
Ex: NaCl(s)  Na+(aq) + Cl-(aq)
Ex: CaCl2(s) Ca+2(aq) + 2Cl-(aq)
Dissociation equations must:
Be balanced
Show correct ionic charges
Show physical states.

28. Properties of Solutions- +
sugar - +
acetic acid - +
salt
Non-
Electrolyte
Weak
Electrolyte
Strong
Electrolyte
solute exists as
molecules only
solute exists as
ions and
molecules
solute exists as
ions only
DISSOCIATION
IONIZATION
View animation online.

29. Molarity Gives us a numerical value to describe concentration
Molarity (M) = moles of solute
liters of solution

30. Molarity
Ex ml of solution contains 3.5 moles of solute. What is the molarity of the solution?

31. Molarity
Ex. 2 To make a 4.00 M solution, how many moles of solute will be needed if 12.0 liters of solution are required?

32. Molarity
Ex. 3
What is the molarity of a solution of HNO3 that contains 12.6 grams HNO3 in 1.0 L of solution?