1. Section 14.3 Factors Affecting Solvation
Describe how intermolecular forces affect solvation.
Define solubility.
Understand what factors affect solubility.
Section 14-3

2. The Solvation Process
The Solvation Process
Attractive forces exist among the particles of all substances
London Dispersion
Dipole-dipole
Hydrogen bonding
If the attractive forces between the solute and the solvent are greater than the attractive forces holding the solute particles together, the solute dissolves in the solvent

3. Solvation in water is called hydration.
The Solvation Process
Solvation
process of surrounding solute particles with solvent particles to form a solution
Solvation in water is called hydration.
The attraction between dipoles of a water molecule and the ions of a crystal are greater than the attraction among ions of a crystal.
Section 14-3

4. The Solvation Process
Section 14-3

5. How do you know if a substance will dissolve?
The general rule is “like dissolves like.”
Polar will dissolve polar (or ionic)
Nonpolar will dissolve nonpolar
Is oil polar or nonpolar?

6. The Solvation Process (cont.)
Sucrose molecules have several O–H bonds, which become sites for hydrogen bonding with water molecules.
Oil does not form a solution with water because there is little attraction between polar water molecules and nonpolar oil molecules.
Section 14-3

7. The Solvation Process (cont.)
During solvation, the solute must separate into particles and move apart, which requires energy.
The overall energy change that occurs during solution formation is called the heat of solution.
Exothermic
energy is released
feels warm or hot.
Endothermic
energy is absorbed
feels cool or cold
Section 14-3

8. Factors That Affect Solvation
Agitation (stirring or shaking)
moves dissolved particles away from the contact surfaces more quickly and allows new collisions to occur.
Surface area
breaking the solute into small pieces increases surface area and allows more collisions to occur.
Temperature
temperature increases, rate of solvation increases.
Section 14-3

9. Solubility depends on the nature of the solute and solvent.
Unsaturated solutions
solutions that contain less dissolved solute for a given temperature and pressure than a saturated solution
Section 14-3

10. Solubility (cont.) Saturated solutions
contain the maximum amount of dissolved solute for a given amount of solute at a specific temperature and pressure
Solubility is affected by increasing the temperature of the solvent because the kinetic energy of the particles increases.
Section 14-3

11. At 40C, the solubility of KBr is 80 g/100 g H2O.
Identify the following solutions as either
1) saturated or (2) unsaturated. Explain.
A. 60 g KBr added to 100 g of water at 40C.
B g KBr added to 200 g of water at 40C.
C. 25 g KBr added to 50 g of water at 40C.

12. Solubility (cont.)
Section 14-3

13. supersaturated solution
Solubility (cont.)
supersaturated solution
contains more dissolved solute than a saturated solution at the same temperature.
To form a supersaturated solution, a saturated solution is formed at high temperature and then slowly cooled.
Supersaturated solutions are unstable.
Section 14-3

14. Solubility (cont.)
Section 14-3

17. Gases are less soluble in liquid solvents at high temperatures.
Solubility (cont.)
Gases are less soluble in liquid solvents at high temperatures.
Solubility of gases increases as its external pressure is increased.
Henry’s law
states that at a given temperature, the solubility (S) of a gas in a liquid is directly proportional to the pressure (P).
Section 14-3

18. If 0. 55 g of a gas dissolves in 1. 0 L of water at 20
If 0.55 g of a gas dissolves in 1.0 L of water at 20.0 kPa of pressure, how much will dissolve at kPa of pressure?
Why do fish die in water that is too warm?
Why could a bottle of carbonated drink possibly burst (explode) when it is left out in the hot sun ?

20. Solubility of solids
in liquids
Solubility of gases
Increase Temperature
Generally increases
Decreases
Increase Pressure
No effect
Increases

21. A B C D Section 14.3 Assessment
For a given amount, which type of solution contains the LEAST amount of solute?
A. solvated
B. saturated
C. supersaturated
D. unsaturated A B C D
Section 14-3

22. A B C D Section 14.3 Assessment
At a given temperature, the solubility of a gas is directly proportional to what?
A. volume
B. mass
C. molarity
D. pressure A B C D
Section 14-3

23. Section 14.3 Factors Affecting Solvation
Key Concepts
The process of solvation involves solute particles surrounded by solvent particles.
Solutions can be unsaturated, saturated, or supersaturated.
Henry’s law states that at a given temperature, the solubility (S) of a gas in a liquid is directly proportional to the pressure (P) of the gas above the liquid.
Study Guide 3