1. Water

2. Water has a Unique Shape
A negative charge on the Oxygen end
Positive charge on the Hydrogen end
You must know this model

3. Hydrogen Bonding
Hydrogen Bonding is a inter-molecular attraction cause by different charges
The H is attracted to the O because of the opposite charge

4. Solutions Solutions are a solute dissolved in a solvent
In salt water; salt is the solute and water is the solvent
Salt dissolves in water because water can separate the ions from each other
The solute particles can not be filtered out of a solution

5. Solvation Solvation occurs when a solute dissolves
Solvation is the process where molecules of the solvent surround the molecules of the solute

6. Kool-Aid Science
What is the solute and the solvent in your Koo-Aid solution?
Solute – the mix Solvent - the water
How strong is your solution?
Is it dilute or concentrated?

7. Concentration What does it mean when a solution is concentrated?
It means that a lot of solute is dissolved in the solution

8. Dilute What does it mean when a solution is dilute?
It means that there is not a lot of solute dissolved in the solvent

9. What the Problem? Concentrated and dilute are relative
Think about coffee
What is strong to one person is not strong to another
These terms do not give a precise description of the solution
We need a need new unit of measurement

10. Molarity Molarity is defined as
Moles (that’s right moles again) divided by liters
.5M means .5 moles per liter
Molarity is the number of moles of solute dissolved in volume of solvent measured in liters
Molarity can also be written in brackets
[2.5] means 2.5 moles per liter
The molarity is 2.5

11. Example
What is the molarity of a solution that has 1 mole of salt dissolved in 500 ml of water
First convert ml into liters
500 ml x 1L/1,000 ml = .5L
Divide moles by liters
1mole/.5L = 2M

12. Another Example
What is the molarity of a solution that has 31 grams of HNO3 in 250 ml of water.
31 x 1 mole/63 grams = .49 moles
250 ml x 1 liter/1,000 ml = .25 liters
.49 moles/.25 liters = 1.96 M

13. What dissolves in What
The rule is like dissolves in like, polar in polar and non-polar in non-polar
Remember that water is polar, so a polar solid will dissolve in it.
This is why non-polar oil will not dissolve in water.

14. Solubility
SOLUBILITY is understood as a maximum amount of solute that dissolves in a solvent
Miscible-
The ability of a liquid to dissolve in another liquid
Example water and vinegar, water and ethanol
Immiscible – two liquids can not dissolve

15. Factors Affecting Solubility
In general solids become more soluble at higher temperatures
Think about making Jello
In general gases become less soluble at higher temperatures but more soluble at higher pressure
Why the rise in global temperature is adversely affecting the oceans

16. Factors Affecting Solubility
Particle size
In general, as particle size increases, solubility decreases
Stirring
Stirring increases solubility by increase contact of the solute and solvent particles
If left alone sugar will dissolve, but stirring increase solubility

17. Degrees of Solubility
You can pour as much solute as you want into a solvent, but only a set amount will dissolve
Solubility is a physical property of a substance in
given in grams of solute per 100 grams of solvent
Ksp is the constant of solubility

18. Solubility Graphs
Solubility graphs show the relationship between temperature and the amount of solute dissolved

19. Terms to know Saturated solution Unsaturated solution
These solutions contain the maximum dissolved solute in the solvent
Unsaturated solution
These solution do not contain the maximum dissolved solute in solution – you can add more
Supersaturated solution
These solutions contain more than maximum due to heating of the solution – rock candy

20. Electrolytes Compounds that conduct electric current in solution
Compounds that do not conduct a current are non-electrolytes
A strong electrolytes have nearly all the solute exists as ions
A weak electrolyte has only a fraction of the solute as ions

21. Suspensions and Colloids
In a suspension the dissolved particles are large and will settle to the bottom
Particles can be filtered out.
Examples sand and water, salad dressing
In a colloid the dissolved particles are intermediate size and exhibit the Tyndall effect
In the Tyndall effect, light will both pass through the colloid and scatter
Examples, milk, fog

22. Other Unique properties of water
The density of water decreases at 0°C
That is why ice floats
The molecules of water in ice arrange themselves in a organized pattern
The molecules in this pattern are more spread out than in the liquid state
Ice takes up mores space than water at 2°C