1. SOLUTIONS
Sections 8.1 & 8.2

2. SOLUTIONS
Solute—A substance whose particles are dissolved in a solution
Solvent—The substance in which the solute dissolves
The solution takes the state of the solvent

3. Solute Solvent Example
Gas
Air
Liquid
Water in air
Carbonated beverages
Vinegar
Solid
Sugar water
Stainless steel

4. Substances can dissolve in water in three ways:
Dissociation—An ionic compound separates into ions as it dissolves
Dispersion—The process involves breaking into smaller pieces
Ionization—Neutral molecules gain or lose electrons

5. PROPERTIES OF LIQUID SOLUTIONS
The three physical properties of a solution that vary from those of its solute and solvent are:
Conductivity
Freezing point
Boiling point

6. SOLUTIONS
During the formation of a solution, energy is either released or absorbed (exothermic OR endothermic)

7. FACTORS AFFECTING RATES OF DISSOLVING
Surface area —The greater the surface area, the more frequent the collisions occur which results in faster dissolving
Stirring —Stirring the solution allows for more collisions
Increasing temperature —increasing the temperature causes the particles in the solvent to move faster, thus there are more collisions

8. SOLUBILITY AND CONCENTRATION
Solubility is the maximum amount of solute that dissolves in a given amount of solvent and a constant temperature

9. Three types of solutions
Saturated solutions hold as much solute as the solvent can hold at a given temperature
Unsaturated solutions have less than the maximum amount of solute that can be dissolved
Supersaturated solutions contain more solute than it normally hold at a given temperature

10. Solubility curve
Which substance does not greatly increase, increases the most, decrease in solubility, as the temp is increased?
If 50g of KCl are dissolved in 100g of water at 50oC, what type of soln is formed?
Which substance is the Most, Least soluble at 0oC?
Which 2 substances have the same solubility at 60oC?
At 30oC which substance, Pb(NO3)2 or KNO3, can form the more concentrated solution?

11. Solubility curve

12. FACTORS AFFECTING SOLUBILITY
Polarity of the solvent— “LIKE DISSOLVES LIKE” meaning that a polar solvent will dissolve a polar solute
Temperature—Temperature increases the solubility of a solid in a liquid but a gas becomes less soluble at higher temperatures
Pressure—Increasing the pressure on a gas increases its solubility in a liquid

13. Concentration
The concentration of a solution is the amount of solute dissolved in a specific amount of solution
Concentration = Solute x 100%
Solution

14. Concentration of solutions
% by volume = Volume of solute x100% Volume of solution
Percent by Mass=Mass of solute x 100%
Mass of solution

15. Examples
What is the concentration if: solute = 15mL and solution = 100mL?
A 300 mL solution contains 50mL of HCl dissolved in 250mL of water. What is the concentration of the HCl? What is the concentration of water?
The relative humidity is 30%. If you sample 1 liter of this air how much of it is water vapor and how much of it is air?