1. Solubility

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

3. of solubility on temperature
Solubility vs. Temperature for Solids
140 KI
130
120
gases
solids
NaNO3
110
Solubility Table
100
KNO3 90 80
HCl
NH4Cl
shows the dependence
of solubility on temperature 70
Solubility (grams of solute/100 g H2O) 60
NH3
KCl 50
“Solubility Curves for Selected Solutes”
Description: This slide is a graph of solubility curves for 10 solutes. It shows the number of grams of solute that will dissolve in 100 grams of water over a temperature range of 0cC to 10 cC.
Basic Concepts
The maximum amount of solute that will dissolve at a given temperature in 100 grams of water is given by the solubility curve for that substance.
When the temperature of a saturated solution decreases, a precipitate forms.
Most solids become more soluble in water as temperature increases, whereas gases become less soluble as temperature increases.
Teaching Suggestions
Use this slide to teach students how to use solubility curves to determine the solubilities of various substances at different temperatures. Direct their attention to the dashed lines; these can be used to find the solubility of KClO3 at 50 cC (about 21 g per 100 g of H2O). Make sure students understand that a point on a solubility curve represents the maximum quantity of a particular solute that can be dissolved in a specified quantity of solvent or solution at a particular temperature. Point out that the solubility curve for a particular solute does not depend on whether other solutes also are present in the solution (unless there is a common-ion effect; this subject usually is covered at a later stage in a chemistry course).
Questions
Determine the solubilities (in water) of the following substance at the indicated temperatures: NH3 at 50 oC; KCl at 90 oC; and NaNO3 at 0 oC.
Which of the substances shown on the graph is most soluble in water at 20 oC? Which is lease soluble at that temperature? For which substance is the solubility lease affected by changes in temperature?
Why do you think solubilities are only shown between 0 oC and 100 oC?
In a flask, you heat a mixture of 120 grams of KClO3 and 300 grams of water until all of the KClO3 has just been dissolved. At what temperature does this occur? You then allow the flask to cool. When you examine it later, the temperature is 64 oC and you notice a white powder in the solution. What has happened? What is the mass of the white powder?
Compare the solubility curves for the gases HCl, NH3, and SO2) with the solubility curves for the solid solutes. What generalizations(s) can you make about the relationship between solubility and temperature?
According to an article in an engineering journal, there is a salt whose solubility in water increases as the water temperature increases from 0 oC to 65 oC. The salt’s solubility then decreases at temperatures above 65 oC, the article states. In your opinion, is such a salt likely to exist? Explain your answer. What could you do to verify the claims of the article? 40 30
NaCl
KClO3 20 10
SO2
LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World , 1996, page 517

4. Solubility Solubility maximum grams of solute that will dissolve
in 100 g of solvent at a given temperature
varies with temp
based on a saturated solution

5. Solubility Solids are more soluble at... high temperatures.
Gases are more soluble at...
low temperatures &
high pressures (Henry’s Law).
EX: nitrogen narcosis, the “bends,” soda

6. Solubility  how much solute dissolves in a given amt.
of solvent at a given temp.
SOLUBILITY
CURVE
Temp. (oC)
Solubility
(g/100 g H2O)
KNO3 (s)
KCl (s)
HCl (g)
unsaturated: solution could hold more solute; below line
saturated: solution has “just right” amt. of solute; on line
supersaturated: solution has “too much” solute dissolved in it;
above the line

7. Solids dissolved in liquids Gases dissolved in liquidsTo
Sol. To
Sol.
As To , solubility
As To , solubility

8. Classify as unsaturated, saturated, or supersaturated.
100 g
H2O
80 g 30oC unsaturated
45 g 60oC saturated
50 g 10oC unsaturated
70 g 70oC supersaturated
Per 500 g H2O, 120 g 40oC
saturation 40oC for 100 g H2O = 66 g KNO3
So sat. 40oC for 500 g H2O = 5 x 66 g = 330 g
120 g < 330 g unsaturated

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

10. Hotpack / Coldpack

11. Hot and Cold Packs Article
Article "Hot and Cold Packs" 
ChemMatters Feb Questions
Article "Hot and Cold Packs"
ChemMatters Feb Questions
Keys

12. Solubility of Sodium Acetate
150
Supersaturated
solution
Saturated
100
Solubility(g/100 g H2O)
Unsaturated
solution
video clip
Add 100 g sodium acetate into 100 g of water at 55oC.
Allow to cool to 20oC. Only 82 g of sodium acetate should remain in solution at this temperature.
Place a seed crystal in the supersaturated solution and ~18 g of sodium acetate will precipitate out of solution.
The resulting solution will be saturated.
Include a table of data for students to graph. 50
A single crystal of sodium acetate,
NaC2H3O2, is dropped into a
supersaturated solution
The small crystal causes extensive
crystallization, and eventually 25 50 75
100
the solute forms a
solid mass of NaC2H3O2.
Temperature (oC)
Charles H.Corwin, Introductory Chemistry 2005, page 378

13. Solubility Equilibrium

14. Vitamins Multi Vitamin Water Soluble Fat Soluble
Provides many essential vitamins
“Expensive urine”
Water Soluble
Vitamin C
Must be replenished regularly
Fat Soluble
Can overdose
Vitamin A
Can be ingested periodically, stored in body fat

15. Steroids Bob Hazelton Article - Steroids
Keys

16. Reverse Osmosis

17. Reverse Osmosis
Kelter, Carr, Scott, Chemistry A Wolrd of Choices 1999, page 267

18. Net Solvent Flow semipermeable membrane Dilute solution
Net flow of solvent
Net flow of solvent
Concentrated
solution
Net solvent flow through a semipermeable membrane occurs spontaneously in only one direction, from the compartment containing dilute solution (or pure solvent) into the compartment of concentrated solution.
Remember –ordinarily the terms dilute and concentrated are used to describe the concentration of solute. The net flow of solvent is from where the solvent is more concentrated to where the solvent is less concentrated.
Solute particle
Solvent particle
Ralph A. Burns, Fundamentals of Chemistry 1999, page 430

19. Gas, Liquid, and Solid
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 441

20. Classes of Reactions Chemical reactions Precipitation reactions
Oxidation-Reduction
Reactions
Acid-Base
Reactions
Combustion
Reactions
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 240

21. Summary of Classes of Reactions
Chemical reactions
Precipitation
reactions
Oxidation-Reduction
Reactions
Acid-Base
Reactions
Combustion
Reactions
Synthesis
reactions
(Reactants are
elements.)
Decomposition
reactions
(Products are
elements.)
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 242

22. Dissociate in Water

23. Hydrogen Bonding Intermolecular forces of attraction between molecules
Bonds exist within
Zumdahl, Zumdahl, DeCoste, World of Chemistry 2002, page 442

24. K+
NO3- K+ K+
NO3-
NO3- K+
NO3-
NO3- K+
NO3- K+
AgCl precipitate
AgCl precipitate

25. Dissolving of NaCl
Timberlake, Chemistry 7th Edition, page 287

26. Solutions

27. Liquid Nitrogen Demonstrations
Keys

28. Titration of Vitamin C with Iodine
Keys

29. Definitions
Solute - KMnO4
Solvent - H2O

30. NaCl(s)  Na+(aq) + Cl–(aq)
Solvation
Dissociation
separation of an ionic solid into aqueous ions
NaCl(s)  Na+(aq) + Cl–(aq)

31. HNO3(aq) + H2O(l)  H3O+(aq) + NO3–(aq)
Solvation
Ionization
breaking apart of some polar molecules into aqueous ions
HNO3(aq) + H2O(l)  H3O+(aq) + NO3–(aq)

32. Solvation C6H12O6(s)  C6H12O6(aq) Molecular Solvation
molecules stay intact
C6H12O6(s)  C6H12O6(aq)