1. Water

4. Unique Structure of Water

5. Dipole Moment
Dipole moment: Used to depict the strength of the charge and the distance between the charge in a polar molecule. A dipole moment allows a molecule to reach
neutrality.
Created when a molecule has slight
“-” & “+” regions.

6. Structure of the Water Molecule
Covalent Bonds & Hydrogen Bonds in H2O
Hydrogen Bond
Covalent Bond

7. Unique Properties of Water
Adhesion
Cohesion
Capillary action
High surface tension
High Specific Heat/heat capacity
High heat of vaporization
Less dense as a solid than a liquid

8. Properties of Water
Cohesion, Adhesion
cohesion = water’s ability to attract to other water
molecules through its polarity
adhesion = water’s ability to attract to different
materials other

9. Properties of Water Capillary Action
Capillary action is created by the adhesive and cohesive properties of water.
Capillary Action - The ability of water to rise through a narrow tube due to water’s adhesive and cohesive properties.
Ex: Water movement up a straw
Ex: Water movement in a tree

10. Properties of Water High Heat Capacity
In order to raise the temperature of water, the average molecular speed has to increase.
It takes much more energy to raise the temperature of water compared to other solvents because hydrogen bonds hold the water molecules together!
Water has a high heat capacity.
“The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius.”
High Heat Capacity

11. Heat of Vaporization
The amount of heat needed to turn a liquid into a gas
Water has a very high heat of vaporization

12. Water is the solvent of Life!
Properties of Water
Universal Solvent
Water is the solvent of Life!
Solute – substance dissolved in a solvent to form a solution
Solvent – fluid that dissolves solutes
Example: Ice Tea – water is the solvent and tea and sugar are the solutes

13. Properties of Water Density
Ice (solid form of water) is less dense than the liquid form of water! Each molecule of water in an ice cube is bound to four of its neighbors by 4 hydrogen bonds.

14. Properties of Water
Covalent bonding
Polar covalent bond – a type of covalent bonding where there is unequal sharing of electrons between atoms
Non Polar Covalent bond – A type of covalent bond where electrons are shared equally

15. Acids and Bases

16. Acids and Bases
Acid – any substance that creates free hydrogen ions
(H+) ormprotons when in solution.
Ranges from pH 0 < 7
Base – any substance that creates free hydroxide (OH-) ions when in solution.
Ranges from pH 7 > 14
pH Scale – Ranges from 0 – 14
Logarithmic Scale (gets 10x bigger/smaller)
Distilled water is pH 7.0 or neutral. Why?
H2O H OH-

18. Acids and Bases
Buffer – an aqueous solution that resists changes in pH. The pH of a buffer remains constant.
H2CO3 H HCO3-
Carbonic acid bicarbonate ion

19. Hydrologic Cycle