1. Water and Solutions

2. Chemistry Basics : MATTER: anything that has mass and occupies space
ELEMENTS (in Periodic Table): make up matter.
ATOMS: make up elements.
made of protons, neutrons, and electrons.
protons are positive, electrons are negative and neutrons have no charge
ION: A charged particle.
Ex.: Na + and Cl- (separated NaCl: salt)
(If the no. of protons and electrons in the atom of an element are NOT the same)

4. Water molecule chemical formula: H2O
Is POLAR:
Different charges in opposite sides of the molecule.
Hydrogen atoms H (+)
Oxygen atom O (-)

5. Hydrogen Bonds hold water molecules together
5. the negative charge on the Oxygen atom attracts the positive charge on the Hydrogen atom (HYDROGEN BOND)

6. It is because of Waters’ Polarity and Hydrogen Bonding that water is able to do Extraordinary things!!

7. Properties of water Properties Adhesion Cohesion
Less dense when frozen
Universal Solvent
High heat of vaporization
High specific heat
Homeostasis

8. ADHESION
Water molecules make hydrogen bonds with different surfaces/substances
Example: Capillary action, as in water moving up a plant stem, transpiration

9. Adhesion Causes water to…
Form spheres & hold onto plant leaves
Attach to a spider web

10. COHESION Water molecules stick together
Results in Surface Tension and produces a Surface Film
surface tension = measure of strength of water at surface

12. LESS DENSE AS SOLID
Liquid water molecules are unstable: hydrogen bonds are constantly breaking and reforming.
Frozen water molecules are stable: hydrogen bonds are “locked” into a crystal

13. Water is Less Dense as a Solid
Which is ice and which is water? 1

14. Why ice really does float:
Air

15. ***Solvents dissolve solutes creating solutions! ***
Universal solvent
Solvent = a substance in which another substance is dissolved in
Solute = a substance dissolved in a solvent
Solution = when a solvent and solute are combined
***Solvents dissolve solutes creating solutions! ***

16. Solution
Ionic compounds disperse as ions in water (Salt = Na+ and Cl-)
Water molecules then attach to the ions dissolved in the solution.

17. polar: it has slightly charged regions.
hydrophilic: Attracted to water
Ex.: water
nonpolar: it does not have charged regions,
hydrophobic: not attracted to water.
Ex.: oil
POLAR DISSOLVES POLAR!
Water is polar so it dissolves all polar molecules (example salt, sugar)
NONPOLAR DISSOLVES NONPOLAR!
Water will not dissolve non-polar molecules (example Oil, grease)

18. High Heat of vaporization
Amount of energy to convert 1g of a substance from a liquid to a gas
As water evaporates, it removes a lot of heat with it (cooling effect).

19. High Specific Heat
Amount of heat needed to raise or lower 1g of a substance 1° C.
Water resists temperature change

20. Homeostasis
Organism’s ability to maintain stable internal conditions despite changing conditions.
Water is important to this process because:
a. It’s a good insulator
b. Resists temperature change
c. Universal solvent
d. Coolant
e. Ice protects against temperature extremes (insulates frozen lakes)

21. pH scales measures ACIDs OR BASEs
The scale goes from values 0 through 14.

22. Acids Bases pH between 0 and 6.9 on the pH scale Taste sour
Corrode metals (acid rain)
Release lots of hydronium ions (H+)
Ex.: lemon juice, vinegar, coke, coffee
Bases
pH between 7.1 and 14 on the pH scale
Taste bitter, chalky
Feel soapy, slippery
Release lots of hydroxide ions (OH-)
Ex.: soaps, detergents, cleaners

23. ACID BASE
H+ = hydronium ion OH- = hydroxide ion

24. Buffer Neutral pH number is 7 Examples: blood, water
Solutions that keep the pH within a particular pH range.
Buffered aspirin has a coting on it to
Keep the acid in your stomach from
dissolving it right away.