1. CH. 2-2 IN CLASS NOTES
PROPERTIES OF WATER

2. Water, Water Everywhere
Interest Grabber
Water, Water Everywhere
Section 2-2
If you have ever seen a photograph of Earth from space, you know that much of the planet is covered by water. Water makes life on Earth possible. If life as we know it exists on some other planet, water must be present to support that life.
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3. 1. THE WATER MOLECULE H2O
NEUTRAL-10 P & 10E
BENT SHAPE P. 40

4. 2. WATER IS A POLAR MOLECULE
O-SLIGHT NEG. CHARGE
H-SLIGHT POS. CHARGE
MOLECULES IN WHICH THE CHARGES ARE UNEVENLY DISTRIBUTED
LIKE A MAGNET W/ POLES
---=_____ & += BETWEEN_____

5. 3. HYDROGEN BONDS--------
NOT AS STRONG AS IONIC OR COVALENT(STRONGEST)
POLAR MOLECULES ATTRACT EACH OTHER—BECAUSE PARTIAL + / -

6. 4. PROPERTIES OF WATER
A. SINGLE MOLECULE MAY HAVE 4 H-BONDS AT THE SAME TIME
B. COHESION-ATTRACTION BETWEEN MOLECULES OF THE SAME SUBSTANCE
EX. WATER BEADS

7. C. ADHESION
ATTRACTION BETWEEN MOLECULES OF DIFFERENT SUBSTANCES
EX: READING A GRAD. CYL.; CAPILLARY ACTION IN PLANTS
ADHESION BETWEEN WATER & GLASS IS STRONGER THAN WATER VS. WATER

8. D. MIXTURE
2 OR MORE ELEMENTS OR COMPOUNDS THAT ARE PHYSICALLY MIXED
EX: SALT/PEP. STIRRED
EARTH’S ATMOSPHERE

9. E. 2 TYPES OF MIXTURES WITH WATER
1. SOLUTIONS-all the compounds are evenly distributed throughout
solute-substance dissolved (salt)
b. solvent-substance in which the solute is dissolved (water)

10. Figure 2-9 NaCI Solution Cl- Cl- Na+ Na+ Water Water Section 2-2
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11. Figure 2-9 NaCI Solution Cl- Cl- Na+ Na+ Water Water Section 2-2
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12. Water & nondissolved material; when some materials do not dissolve
2. SUSPENSIONS
Water & nondissolved material; when some materials do not dissolve
Ex. Blood & components

13. THE REACTION CAN OCCUR IN BOTH DIRECTIONS
DOUBLE ARROW MEANS…..
THE REACTION CAN OCCUR IN BOTH DIRECTIONS
ARROW MEANS “FORMS” OR “PRODUCES”

14. CHEMICAL EQUATION
H2O H OH—
REACTANTS PRODUCTS
BEFORE AFTER

15. pH Scale Increasingly Basic Neutral Increasingly Acidic Section 2-2
Oven cleaner
Bleach
Ammonia solution
Increasingly Basic
Soap
Sea water
Human blood
Neutral
Pure water
Milk
Normal
rainfall
Acid rain
Increasingly Acidic
Tomato
juice
Lemon juice
Stomach acid
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16. 1. What is pH used for?
To determine acids, bases and neutral substances

17. 2. What does the pH value 7 mean?
There is an equal number of H+ ions and OH- ions. Example: pure water; neutral

18. 3. Substances with a pH value above 7 are considered bases.
Under 7 are considered acids

19. 4. What is the purpose for using a known base, a known acid, and distilled water?
The control part of the lab. To make sure the pH paper is working properly.

20. A water molecule can react to form ions. H2O H+ + OH— Water forms
5. ACIDS, BASES AND pH
A water molecule can react to form ions.
H2O H OH—
Water forms
hydrogen +hydroxide
ion ion

21. 6. pH Scale= Potential or Power of Hydrogen
Indicates the concentration of H+ ions in a solution
Ranges from 0-14
pH 7= H+ and OH- are equal------pure water=7 NEUTRAL

22. 7. Acidic-any compound that forms H+ ions in solution
pH below 7, more H+ ions than OH- ions
The lower the pH the greater the acidity
Ex: HCl-hydrochloric acid
In your stomach=______

23. 8. Base-any compound that produces OH- ions in a solution
A.K.A= Alkaline
Lower concentrations of H+ ions than water, more OH- ions
pH value above 7
Ex: oven cleaner=_______

24. PREVENT SHARP CHANGES IN pH Human body cells-pH 6.5-7.5-homeostasis
E. BUFFERS
WEAK ACIDS OR BASES
PREVENT SHARP CHANGES IN pH
Human body cells-pH
homeostasis