1. SOLUTIONS

2. Aqueous Solution – a short video
Aqueous - water that contains dissolved substances
Solute Solvent
Dissolved particles Dissolving medium
Being dissolved Doing the dissolving

3. 15.2
Solvents and Solutes

4. 15.2
Solvents and Solutes
If you filter a solution through filter paper, both the solute and the solvent pass through the filter.
A solution cannot be separated by filtration. The small size of the solute particles allows them to pass through filter paper.

5. How Can We Increase Solubility?
16.1
Solution Formation
How Can We Increase Solubility?

6. Stirring and Solution Formation
16.1
Solution Formation
Stirring and Solution Formation
Bring fresh solvent (the water in tea) is continually brought into contact with the surface of the solute (sugar).
More contact with solvent = faster to dissolve (not more to dissolve)

7. Higher temperature = more kinetic energy
16.1
Solution Formation
Temperature and Solution Formation
Higher temperature = more kinetic energy
More kinetic energy = more molecular movement
Equals faster dissolving time and increase in solubility

8. The bigger the molecule the less soluble it is.
16.1
Solution Formation
Particle Size
The bigger the molecule the less soluble it is.
Smaller “pieces” dissolve faster.

9. Solubility is often expressed in grams of solute per 100 g of solvent.
16.1
Solubility
SOLUBILITY
The amount of solute that dissolves in a given quantity of a solvent at a specified temperature and pressure to produce a saturated solution.
Solubility is often expressed in grams of solute per 100 g of solvent.

10. Solutions Unsaturated Solution Can hold more solute NO equilibrium
NO solute on bottom
Saturated Solution
CANNOT hold more solute
Equilibrium Established
SOMETIMES solute on bottom (if we add too much)

11. Factors Affecting Solubility
16.1
Factors Affecting Solubility
A supersaturated solution contains more solute than it can theoretically hold at a given temperature.
The crystallization of a supersaturated solution can be initiated if a very small crystal, called a seed crystal, of the solute is added.
Watch it happen!

12. Rate of dissolving = rate of crystallization
16.1
Solubility
Solution Equilibrium
Rate of dissolving = rate of crystallization
Occurs only in a saturated solution
du/en/simulation/sol uble-salts
In a saturated solution, a state of dynamic equilibrium exists between the solution and the excess solute. The rate of solvation (dissolving) equals the rate of crystallization, so the total amount of dissolved solute remains constant. Inferring What would happen if you added more solute?

13. You have to know molar mass!
16.2
Molarity
Molarity
How do you calculate the molarity of a solution?
Molarity (M) is the number of moles of solute dissolved in one liter of solution.
You have to know molar mass!

14. 16.2
Molarity
Molarity
Calculate the molarity of a solution which contains 0.40 mol of a substance dissolved in 1.6 L of a solution.

15. 16.2
Molarity
Molarity
What is the molarity of a solution containing 325 g of NaCl dissolved in 750. mL of solution?

16. 16.2
Molarity
Molarity
You are making 2.2 L of 3.1 M silver nitrate solution. Who many moles of solute are there?

17. Colligative Properties
16.2
Molarity
Colligative Properties
What is happens when salt is added to water
And……
We try to freeze it?
We try to boil it?

18. Equilibrium Try this simulations for 2017
Equilibrium

19. Can You…. Define Le Chatelier’s Principle?
Describe the three ways to change the equilibrium in a system?
Predict which direction a reaction will proceed when a stress is applied to a system?

20. What is Equilibrium Reversible Reactions
Products can react to re-form the reactants
Shown with a double arrow
Chemical Equilibrium
When the rate of the forward equals the rate of the reverse

21. What is “K” or the Equilibrium Constant?
What is Equilibrium
What is “K” or the Equilibrium Constant?
Less than 1
more reactants present
Equilibrium lies to the left
Reactant favored
Equal to 1
equal amount of product and reactant
Neither products or reactants favored
Greater than 1 = more products present
More products present
Equilibrium lies to the right
Product favored

22. What is Equilibrium A Sample Problem
Given the data below, calculate the value for the equilibrium constant.
2 NO (g) + Cl2(g) ⇌ 2 NOCl (g)
At equilibrium [NO (g)] = 1.20 M
[Cl2(g)] = 0.75 M
[NOCl (g)] = 0.88 M

23. Le Chatelier’s Principle
If a system is stressed, the equilibrium will shift to relieve the stress
Three Methods to Stress A System
Add/Remove a substance
Change the temperature
Change the pressure
LEARN BY DOING!!!!!

24. Change the Pressure Increase pressure = go to side with less gas
Decrease the pressure = go to side with more gas
2 NO2(g)  N2O4(g)
Increase the pressure =
Decrease the pressure =

25. Change the Temperature
Endothermic Reactions
Energy as reactant
Uses energy
Units of energy = kJ = kilojoules
Feels cold to the touch
Exothermic Reactions
Energy as product
Produces energy
Feels warm to the touch

26. Change the Temperature
Increase temperature – shift away from heat
Decrease temperature – shift towards heat
556kJ CaCO3 (s)  CaO (s) CO2 (g)
Type of Reaction
Increase temperature
Decrease Temperature

27. Change the Concentration
If you add, shift away from what you add
If you remove, shift towards to remake
Adding solids or liquids does not change equilibrium
Example
345kJ NH4Cl (s) ↔ NH3 (g) HCl(g)
Add NH4Cl
Add NH3   
Remove HCl
Add Heat