1. Chapters 12-13: Solutions
Modern Chemistry

2. Solution Solution – a homogeneous mixture of a solute and a solvent.
soluble - capable of being dissolved
Solute – the chemical that is dissolved
Solvent – the substance it is dissolved in
Ex.) Salt in water
Different types depend on state of solute/solvents:
Solid-liquid
Liquid-liquid
Gas-liquid
Liquid-gas
Solid-solid
Gas-gas

4. A substance that dissolves in water to give a solution that conducts electric current is called an electrolyte.
Any soluble ionic compound, such as sodium chloride, NaCl, is an electrolyte.

6. Do all compounds dissolve as well as others?No
Solubility - Maximum amount of solute that can dissolve in a given amount of solvent at a given temperature

7. Factors affecting solubility
1. “Like dissolves like”
Polar solvents – dissolve ionic/polar solutes
Nonpolar solvents – dissolve nonpolar solutes
2. Pressure
No impact on solid-liquid solutions
For gas-liquid solutions,  P  Solubility
3. Temperature
Solid-liquid solutions, T Solubility
Gas- liquid solutions, T Solubility

8. Speed of solution formation
Impacted by: 1. surface area 2. agitation 3. temperature

9. Once a solution forms…
Saturated solution – contains the maximum amount of solute Unsaturated solution – contains less than the maximum amount of solute Supersaturated solution – contains more than the maximum amount of solute

10. Heat of solution Energy change when a solution forms
Exothermic – releases energy (hot)
Endothermic – absorbs energy (cold)

11. Solutions calculations
1. Molarity
2. Dilutions
3. Molality

12. 1. Molarity, M Moles solute Liters solution M = M 1 mol L =
Molarity is a standard used to express the concentration of a solution
Moles solute
Liters solution M = M 1
mol L =

13. Example:
You have 3.50 L of solution that contains g of sodium chloride, NaCl. What is the molarity of that solution?
You have 0.8 L of a 0.5 M HCl solution. How many moles of HCl does this solution contain?

14. To produce 40. 0 g of silver chromate, you will need at least 23
To produce 40.0 g of silver chromate, you will need at least 23.4 g of potassium chromate in solution as a reactant. All you have on hand is 5 L of a 6.0 M K2CrO4 solution. What volume of the solution is needed to give you the 23.4 g K2CrO4 needed for the reaction?

15. 2. Dilutions
The dilution equation is used to accurately make weaker solutions from stronger stock solutions by adding water
M1V1 = M2V2
Initial Molarity x initial volume = final Molarity x final volume
Stock solution
Weaker solution

16. Example
If you have 5L of a 12M HCl solution and you want a 3.5M solution, how much water should you add?
If you have 2L of a 8.5M HCl solution and you accidentally added 0.65L of distilled water, what is the new molarity?

17. 3. Molality, m m 1 moles solute kg solvent = m 1 mol kg =
Another standard for showing concentration of a solution m 1
moles solute
kg solvent = m 1
mol kg =

18. Examples
A solution was prepared by dissolving 17.1 g of sucrose (table sugar, C12H22O11) in 125 g of water. Find the molal concentration of this solution.

19. Examples cont.
A solution of iodine, I2, in carbon tetrachloride, CCl4, is used when iodine is needed for certain chemical tests. How much iodine must be added to prepare a m solution of iodine in CCl4 if g of CCl4 is used?

20. Chapter 12 Review
Page 426
#’s 2-5, 7-9, 11-12, 17, 19-22, 26-29

21. CHAPTER 13

22. Compounds in Aqueous Solutions
Dissociation- soluble compounds separate into ions
NaCl(s)  Na+(aq) + Cl-(aq)
CaCl2(s) 
Ca3(PO4)2 

24. How many moles are produced when you dissociate Al2(SO4)3 ?
How many moles are produced when you dissolve 1 mole of sodium carbonate?

25. General Solubility Guidelines

26. Putting solutions together
Basically, just double replacement reactions
Must determine what precipitates out
Use the solubility rules to predict
Cd(NO3)2 (aq) + (NH4)2S (aq)  CdS + 2NH4NO3
(s)
(aq)
Which is the precipitate?

27. What precipitate forms when you mix lead nitrate and potassium iodide?
Pb(NO3)2 (aq) + 2KI (aq)  2KNO PbI2

28. Identify the precipitate that forms when aqueous solutions of zinc nitrate and ammonium sulfide are combined. Write the equation for the possible double- displacement reaction and include the states of matter.

29. Spectator ions – do not take part in a chemical reaction
Net Ionic Equation – includes only the compounds that undergo a chemical change in the reaction
Spectator ions – do not take part in a chemical reaction
Hint: Watch for a phase change!
Solubility Table pg. 437
Common ion chart pg. 858

30. Pb(NO3)2 (aq) + 2KI (aq)  2KNO3 (aq) + PbI2 (s)
Pb2+(aq) +
2NO3-(aq) +
2K+(aq) +
2I-(aq)
2K+(aq) +
2NO3-(aq)
PbI2 (s)
Spectator ions
Called complete ionic equation
**To write net ionic equation, eliminate substances that undergo no change**
Remember, ionic compounds, dissociate in solution
Pb2+(aq) + 2I-(aq)  PbI2 (s)
Net ionic equation

31. Write complete ionic and net ionic for:
1. Potassium sulfate and barium nitrate
2. Silver nitrate and sodium chloride

32. Net ionic equation
Strontium nitrate and sodium sulfate

33. Solution types Electrolyte – conducts electricity
Strong electrolytes vs. weak electrolytes
HCl vs. HF
Nonelectrolyte – does not conduct electricity

34. Colligative Properties
Properties that depend on the concentration of solute particles
Vapor Pressure
Freezing Point
Boiling Point

35. 1. Vapor Pressure Lowering
Add solute, vapor pressure goes down (so boiling point goes up)
Non-volatile substance – is one that has little tendency to become a gas under existing conditions

36. 2. Freezing Point Depression
Add solute, freezing point goes down
Kf= freezing point constant = -1.86℃
Tf = Kf x m
Ex.) Determine the freezing point of a water solution of fructose, C6H12O6, made by dissolving 58.0g of fructose in 185g of water.

37. Ex2. ) Calculate the molality of a solution of 39
Ex2.) Calculate the molality of a solution of 39.2g of urea, H4N2CO, in 485g of pure acetic acid. Determine the freezing point of this solution.

38. A solution consists of 10.3g of glucose, C6H12O6, dissolved in 250g of water. What is the freezing point depression of the solution?

39. 3. Boiling Point Elevation
Add solute, boiling point goes up
Kb = molal boiling point constant = 0.51℃
Tb = Kb x m
Ex. A solution contains 50g of sucrose, C12H22O11, dissolved in 500g of water. What is the boiling point elevation?

40. Ex2. If the boiling point elevation of an aqueous solution containing a nonvolatile electrolyte is 1.02℃, what is the molality of the solution?

41. A solution contains 450.0g of sucrose C12H22O11, a nonelectrolyte, dissolved in g of acetic acid. What is the boiling point of the solution?

42. In World War II, soldiers in the Sahara Desert needed a supply of antifreeze to protect the radiators of their vehicles. The temperature in the Sahara almost never drops to 0°C, so why was the antifreeze necessary?

43. Chapter 13 Review
Pg. 458
#’s 1-3, 5, 8, 9, 11, 12, 14, 19, 20, 21, 25, 26, 30