1. Solutions

2. What are ways that you make a solute dissolve faster?
Rate of Solution
What are ways that you make a solute dissolve faster?
Increase the temperature.
Crush or use smaller size solute particles.
Stir the solutions.

3. Types of Solutions There are three ways to classify a solution.
Unsaturated Solutions
Saturated Solutions
Supersaturated Solutions

4. Relation to Solubility Curve
Types of Solutions
Type of Solution
Description
Picture
Relation to Solubility Curve
Unsaturated
Saturated
Supersaturated
A solution in which more solute can dissolve
Below the
Line
A solution in which contains the maximum amount of solute
On the
Line
See PDF for pictures
Above the
Line
A solution in which contains more than the maximum amount of solute

5. Supersaturated
The solution is holding more solute than it should be able to. This is achieved by heating the solution and then cooling it slowly.
Examples: rock candy, southern style sweet tea, chemical heat packs
Supersaturated solutions are unstable. The supersaturation is only temporary

6. SUPERSATURATED SOLUTION
Solubility
UNSATURATED SOLUTION
more solute dissolves
SATURATED SOLUTION
no more solute dissolves
SUPERSATURATED SOLUTION
becomes unstable, crystals form
increasing concentration

7. Supersaturated

8. Solubility Curves
Solubility indicates the amount of solute that will dissolve in a given amount of solvent at a specific temperature.
For this curve,
X-Axis
Temperature
Y-Axis
How Much Solute Dissolves in 100g of Water
Various Lines
Each line represents a different solute.

9. Solubility Curves
Supersaturated
CO2
Saturated
Unsaturated

10. Using an available solubility curve, classify as
unsaturated, saturated,
or supersaturated.
80 g 30oC
per 100 g H2O
unsaturated
45 g 60oC
saturated
30 g 30oC
supersaturated
70 g 60oC
unsaturated

11. Describe each situation below.
(A) Per 100 g H2O,
100 g 50oC.
unsaturated;
all solute dissolves;
clear solution.
(B) Cool solution (A) very
slowly to 10oC.
supersaturated;
extra solute remains
in solution; still clear
(C) Quench solution (A) in
an ice bath to 10oC.
saturated; extra solute (20 g)
can’t remain in solution and becomes visible

12. How to use a solubility graph?
A. IDENTIFYING A SUBSTANCE ( given the solubility in g/100 cm3 of water and the temperature)
Look for the intersection of the solubility and temperature.

13. Using Solubility Curves
How much KNO3 would dissolve in 100g of water at 50oC?
How much NH4Cl would dissolve in 200g of water at 70oC?
At what temperature would 22g of KCl be able to dissolve in 50g of water?
Which is more soluble (has a higher solubility) at 40oC?
NH3
KClO3
84g
120g
68oC

14. Learning Check : What substance has a solubility of 90 g/100 cm3 in water at a temperature of 25ºC ?

16. Learning Check :
What substance has a solubility of 200 g/100 cm3 of water at a temperature of 90ºC ?

18. Look for the temperature or solubility
Locate the solubility curve needed and see for a given temperature, which solubility it lines up with and visa versa.

19. Learning Check:
What is the solubility of potassium nitrate at 80ºC ?

20. What is the solubility of potassium nitrate at 80ºC ?

21. Learning Check :
At what temperature will sodium nitrate have a solubility of 95 g/100 cm3 ?

22. Learning Check:
At what temperature will sodium nitrate have a solubility of 95 g/100 cm3 ?

23. Learning Check:
At what temperature will potassium iodide have a solubility of 230 g/100 cm3 ?

24. Learning Check:
At what temperature will potassium iodide have a solubility of 130 g/100 cm3 ?

25. Using Solubility Curves:
What is the solubility of sodium chloride at 25ºC in 100 cm3 of water ?
From the solubility graph we see that sodium chlorides solubility is 36 g.

26. SOLUBLE OR INSOLUBLE? Soluble: able to be dissolved Insoluble:
does not dissolve in solution (or water)
Precipitate:
an insoluble solid formed when two solutions are mixed

27. Soluble compounds contain…
Insoluble compounds contain…
For these compounds, common exceptions are INSOLUBLE.
SOLUBLE.

28. Double Replacement reactions
AB + CD → AD + CB
NaCl + AgNO3 → NaNO3 + AgCl

29. Concentration of Solute
The amount of solute in a solution is given by its concentration.
Molarity ( M ) =
moles solute
liters of solution

30. Step 1: Calculate moles of NiCl2•6H2O
PROBLEM: Dissolve 5.00 g of NiCl2•6 H2O in enough water to make 250 mL of solution. Calculate the Molarity.
Known
Mass=5 g
Volume = L
Unknown
Molarity of
NiCl2•6 H2O ?
Analysis
molar mass = g
M= n/ V;
Step 1: Calculate moles of NiCl2•6H2O
Step 2: Calculate Molarity
[NiCl2•6 H2O ] = M

31. MOLARITY PROBLEM
What mass of oxalic acid, H2C2O4, is required to make 250. mL of a M solution?
Known
Volume = L
M = moles/L
Unknown
g of H2C2O4,?
Analysis
molar mass = g
M= mol/ V;
Step 1: Calculate moles of H2C2O4
( mol/L) x (0.250 L) = moles
Step 2: Convert moles to grams
mol H2C2O4 x (90.00 g/mol) = g H2C2O4
1 mol H2C2O4

32. Learning Check
How many grams of NaOH are required to prepare 400. mL of 3.0 M NaOH solution?
1) 12 g
2) 48 g
3) 300 g

33. Making Molar Solutions
…from liquids
(More accurately, from stock solutions)

34. Dilution is the procedure for preparing a less concentrated solution from a more concentrated solution.
Dilution
Add Solvent
Moles of solute
before dilution (i)
after dilution (f) =
MiVi
MfVf =
4.5

35. Making a Dilute Solution
remove
sample
moles of
solute
initial solution
same number of
moles of solute
in a larger volume
mix
Making a Dilute Solution
diluted solution
Timberlake, Chemistry 7th Edition, page 344

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

37. Dilution Practice Problem
What volume of 15.8M HNO3 is required to make 250 mL of a 6.0M solution?
Known
Molarity1 = 15.8 mol/L of HNO3
Volume2 = 250 mL
Molarity2 = 6.0 mol/L of HNO3
Unknown
Volume of HNO3?
Equation
M1V1 = M2V2
Solution :
V1 = (6.0 mol/L x L) / 15.8 M = L

38. Dilution Practice Problem
If we have 1 L of 3 M HCl, what is M if we dilute acid to 6 L?
Known
Molarity1 = 3 mol/L
Volume1 = 1 L of HCl
Volume2 = 6L of HCl
Unknown
Molarity of HCl?
Equation
M1V1 = M2V2;
Solution :
M2 = (3 mol/L x 1 L) / (6 L) = 0.5 M

39. Dilution Practice Problem
What volume of 0.5 M HCl can be prepared from 1 L of
12 M HCl?
Solution :
V2 = (12 mol/L x 1 L) / (0.5 L) = 24 L
Known
Volume1 = 1 L of HCl
Molarity1 = 12 mol/L of HCl
Molarity2 = 0.5 mol/L of HCl
Unknown
Volume of HCl?
Equation
M1V1 = M2V2