1. Solutions

2. What on earth does this have to do with chemistry?
Chemistry Joke
What on earth does this have to do with chemistry?
It’s a lit-moose test!

3. Solutions Homogeneous Mixtures Composed of a solute and a solvent
Uniform throughout
Composed of a solute and a solvent
The solute is dissolved into the solvent
The solute or the solvent can be a gas, a liquid, or a solid.
Air: gas / gas solution
Salt water: solid / liquid solution
Carbonated water: gas / liquid solution
Steel: solid / solid solution

7. “Like Dissolves Like” Polar solvents dissolve polar solutes
Water is a polar molecule. It has an uneven distribution of charge.
Water will easily dissolve polar solutes such NaCl.

8. “Like Dissolves Like” Nonpolar solvents dissolve nonpolar solutes
Gasoline is a nonpolar molecule. It has an even distribution of charge.
Gasoline is often used as a solvent to clean nonpolar grease from machine parts.

9. Making Solutions
In order to dissolve, the solvent molecules must come in contact with the solute.
Process is called solvation.
3 Factors that affect the rate
Stirring (agitation)
Particle size (surface area)
Temperature

10. Stirring moves fresh solvent into contact with the solute.
Making Solutions
Stirring moves fresh solvent into contact with the solute.
It’s why we stir iced tea when we add sugar.
2. Smaller pieces increase the amount of surface area of the solute.
Think of how fast a breath mint dissolves when you chew it

11. Slowest Faster Fastest Making Solutions
3. Higher temperature makes the molecules of the solvent move around faster and contact the solute harder and more often.
Slowest
Faster
Fastest

12. Making Solutions So, the rate of solubility is affected by:
Stirring, Particle Size, & Temperature
What determines the amount of solute that will dissolve?
Temperature & Pressure

13. Making Solutions Temperature:
Affects the solubility of solids, liquids, and gases.
For most solids and liquids, the solubility increases with increasing temps.
For most gases, the solubility decreases with increasing temps.
As carbonated drinks get warm, they get “flat”

14. Effect of Temperature
The mineral deposits around hot springs result from the cooling of the hot, saturated solution of minerals emerging from the spring.

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16. Affects only the solubility of gases.
Effect of Pressure
Pressure:
Affects only the solubility of gases.
Gas solubility increases as the partial pressure of the gas above the solution increases.

17. How Is Solubility Expressed?
Max amount of a substance that will dissolve at a specific temp.
Units are g solute/ 100 g solvent.
Saturated
Contains the max amount of solute that can dissolve
Rate of particles dissolving equals rate of particles crystalizing.

18. How Is Solubility Expressed?
Unsaturated
Can still dissolve more solute
Supersaturated
Holds more than it can theoretically contain

19. How Is Solubility Expressed?
Electrolytes
Compounds that conduct electricity in aqueous solution or in a molten state
All ionic compounds are electrolytes
Some ionic compounds are strong electrolytes; others are weak electrolytes.
Strong electrolytes dissociate (break apart) completely.
Weak electrolytes only partially dissociate.

20. How Is Solubility Expressed?
Most molecular compounds do not conduct electricity.
Called nonelectrolytes
Sugar and rubbing alcohol are nonelectrolytes

21. NaCl: Strong Electrolyte
HgCl2: Weak Electrolyte
Glucose: NonElectrolyte

22. Colligative Properties
Properties that affect solutions.
Depends only on the number of dissolved solute particles—not on what kind of particle they are
Two important colligative properties are:
Boiling point elevation
As solute particles are added to a solution, the boiling point rises.
Freezing point depression
As solute particles are added to a solution, the freezing point lowers.

23. Ionic compounds work best because they dissociate in water into more particles.
In water, NaCl becomes Na+ and Cl-.

24. Chemistry Joke
Q: Why did the white bear dissolve in water?
A: Because it was polar!!