1. SOLUTIONS

2. Classification of Matter
Solutions are homogeneous mixtures
Classification of Matter

3. Solute - substance being dissolved
Definitions
Solution - homogeneous mixture
(remember, the particles are so tiny they don’t settle out like in heterogeneous mixtures)
Solute - substance being dissolved
Solvent - present in greater amount

4. Definitions
Solute - KMnO4
Solvent - H2O

5. Solubility Solubility tells us how well something dissolves
Soluble: Dissolves
Insoluble: Doesn’t dissolve
Solubility definition:
maximum grams of solute that will dissolve in 100 g of solvent at a given temperature
Related to the saturation of a solution

6. Saturation Unsaturated: Saturated Supersaturated Not full
More solute can be dissolved in the solvent
Saturated
Full
More solute CANNOT be dissolved in the solvent
Supersaturated
Over Full
More solute has been added than normal
Usually because you’ve added heat to the solvent.

7. Solubility UNSATURATED SOLUTION more solute dissolves
no more solute dissolves
SUPERSATURATED SOLUTION
becomes unstable, crystals form
concentration

8. Factors that affect Solubility & Dissolving
Surface Area
If the solute covers more surface area, it will dissolve faster
Ex. Cube of sugar vs sugar particles
Stirring
Stirring speeds up dissolving time
Think of how long you would have to wait if you didn’t stir your chocolate syrup into your milk
Temperature
Hotter temperatures= Faster
Hotter temperatures = More soluble
For gases, colder temperatures are more favorable

10. Polarity (again)
If a solute will dissolve in a solvent depends on the polarity
Remember: Like Dissolves Like
Polar dissolves Polar
Non-Polar dissolves Non-Polar
If things don’t mix then they have different polarities
Some definitons
Miscible: Liquids that mix together
Immiscible: Liquids that don’t mix together

11. “Like Dissolves Like”
NONPOLAR
POLAR

12. Colligative Properties
properties that depend on the concentration of solute particles but not on their identity
Boiling points and freezing points of solutions differ from those of pure solvent.

13. Change in Freezing Point
Ethylene glycol/water
solution
Pure water
The freezing point of a solution is LOWER than that of the pure solvent
Protects engine from Freezing

14. Change in Freezing Point
Common Applications of Freezing Point Depression
Ethylene glycol – deadly to small animals
Propylene glycol

15. Change in Boiling Point
Ethylene glycol/water
solution
Pure water
The boiling point of a solution is HIGHER than that of the pure solvent
Protects engine from overheating

16. Concentration
Concentration: The amount of solute dissolved in a given amount of solvent
Dilute= low concentration of solute
Concentrated= High concentration of solute
Three ways to calculate concentration
Molarity (M) THE MOST COMMON!!
Percent Concenrtation (%m/v), (%m/m) , (%v/v)
Molality (m)

17. Concentrated vs. Dilute

18. Calculations of Solution Concentration: Mass Percent
Mass percent is the ratio of mass units of solute to mass units of solution, expressed as a percent

19. Mass % by Volume
Sometimes you will see Mass % as a function of volume of solvent instead of mass of solvent

20. A Simplifying Assumption
1 ml of water = 1 gram of water
1000 ml of water = 1 liter = grams
Assume that solutions with water as the solvent have the density of pure water (1 mL = 1 gram)
It’s not true, but it’s close enough 

21. VOLUME %
is the ratio of volume units of solute to volume units of solution, expressed as a percent

22. What is the percent concentration of 2
What is the percent concentration of 2.7 g of glucose in 75 mL of water?

23. 85 mL of ethanol is diluted to 250 mL of solution
85 mL of ethanol is diluted to 250 mL of solution. What is the % concentration of ethanol?

24. How many mL of H2O2 are in a 400 mL bottle of 3.0% (v/v) solution?

25. Molality
mass of solvent only
1 kg water = 1 L water

26. 75 g MgCl2 1 mol MgCl2 95.21 g MgCl2 0.25 kg water = 3.2m MgCl2
Molality
Find the molality of a solution containing 75 g of MgCl2 in 250 mL of water.
75 g MgCl2
1 mol MgCl2
95.21 g MgCl2
0.25 kg water
= 3.2m MgCl2

27. 0.500 kg water 1.54 mol NaCl 1 kg water 58.44 g NaCl 1 mol NaCl
Molality
How many grams of NaCl are req’d to make a 1.54m solution using kg of water?
0.500 kg water
1.54 mol NaCl
1 kg water
58.44 g NaCl
1 mol NaCl
= 45.0 g NaCl

28. M = mol L Molarity The most common way we measure concentration
Moles of solute per Liters of Solution (not just solvent, but amount solute+solvent)
In some problems:
you may need to convert grams to moles first
You may need to convert mL to L
M = mol L

29. 6.02  1023 molar mass MOLES Molarity
(particles/mol)
molar mass
(g/mol)
MASS IN
GRAMS
MOLES
NUMBER OF
PARTICLES
LITERS
SOLUTION
Molarity
(mol/L)

30. substance being dissolved
total combined volume

31. What is the concentration of a solution made from 0
What is the concentration of a solution made from 0.2 moles of KCL in 0.6 L of water?

32. You have 5. 50 L of solution that contains 190 g of NaCl
You have 5.50 L of solution that contains 190 g of NaCl. What is the molarity of the solution?

33. How much distilled water (in mL) would be required to make a 0
How much distilled water (in mL) would be required to make a 0.4 M solution using 32 g of NaNO3?

34. Dilution
Preparation of a desired solution by adding water to a concentrate.
Moles of solute remain the same.

36. GIVEN: M1 = 15.8M V1 = ? M2 = 6.0M V2 = 250 mL WORK: M1 V1 = M2 V2
Dilution
What volume of 15.8M HNO3 is required to make 250 mL of a 6.0M solution?
GIVEN:
M1 = 15.8M
V1 = ?
M2 = 6.0M
V2 = 250 mL
WORK:
M1 V1 = M2 V2
(15.8M) V1 = (6.0M)(250mL)
V1 = 95 mL of 15.8M HNO3

37. DILUTION
How many milliliters of a stock (or standard) solution of 4.00M KI would you need to prepare 250 mL of 0.760M KI?

38. DILUTION
Suppose you need 250 mL of a a0.20 M NaCl, but the only supply of sodium chloride you have is a solution of 1.0 M NaCl. How do you prepare the required solution solution?

39. Preparing Solutions
Weigh out a solid solute and dissolve in a given quantity of solvent.
Dilute a concentrated solution to give one that is less concentrated.

40. Solution Stoichiometry
Just like you have done before!
STEPS
Write the balanced equation for the reaction
Calculate the moles of reactants
Determine which reactant is limiting
Calculate the moles of other reactants or products, as required
Convert to grams or other units, if required

41. Calculate the mass of solid NaCl that must be added to a 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.
AgNO3 + NaCl  AgCl + NaNO3

42. When Ba(NO3)2 and K2CrO4 react in aqueous solution, the yellow solid BaCrO4 is formed. Calculate the mass of BaCrO4 that forms when 3.50 x 10-3 mole of solid Ba(NO3)2 is dissolved in 265 mL of M of K2CrO4 solution