2. Composition of Water Two Hydrogen atoms and One Oxygen atom Two Hydrogen atoms and One Oxygen atom The molecular formula for water is H 2 O. The molecular formula for water is H 2 O.

3. Polarity – The most important property of water is that it is polar.The most important property of water is that it is polar. –A water molecule is polar because there is an uneven distribution of electrons between the oxygen and hydrogen atoms. –The hydrogen end of the molecule is slightly positive and the oxygen end is slightly negative.

4. Bohr Model of Water

5. Water molecules can attract to each other because of this polarity. Water molecules can attract to each other because of this polarity. The attraction between the oxygen atom (slightly negative) on one water molecule and the hydrogen atom (slightly positive) on another water molecule is an example of a hydrogen bond. The attraction between the oxygen atom (slightly negative) on one water molecule and the hydrogen atom (slightly positive) on another water molecule is an example of a hydrogen bond.

6. Hydrogen Bonds

7. Water’s ability to form, hydrogen bonds is responsible for many of its properties. Some of these properties are: –C–C–C–Cohesion SSSSurface Tension –A–A–A–Adhesion CCCCapillary Action

8. Cohesion – An attraction between molecules of the same substance. Cohesion is the reason why water forms beads on a smooth surface. Cohesion is the reason why water forms beads on a smooth surface.

9. Surface Tension The attraction between water molecules causes a condition known as surface tension. The attraction between water molecules causes a condition known as surface tension.

10. Adhesion – is an attraction between different substances. Adhesion powers a process called capillary action, in which water molecules move upward through a narrow tube, such as the stem of a plant. Adhesion powers a process called capillary action, in which water molecules move upward through a narrow tube, such as the stem of a plant.

11. WATER – It does a body GOOD!!! Nearly 65-70% of your body is made of water, water helps move nutrients and other substances into and out of your cells. Nearly 65-70% of your body is made of water, water helps move nutrients and other substances into and out of your cells.

12. Hydrophilic – Used to describe molecules or molecular groups that are attracted to water and other polar solvents. Hydrophilic – Used to describe molecules or molecular groups that are attracted to water and other polar solvents.

13. Hydrophobic – Used to describe molecules or molecular groups that mix poorly with water. Hydrocarbons and fats are hydrophobic. Hydrophobic – Used to describe molecules or molecular groups that mix poorly with water. Hydrocarbons and fats are hydrophobic.