1. How Important Is Water???

2. Water (H2O) 70% of your body is made of water
2/3 of the molecules in your body are water molecules

3. I. Structure of Water (H2O)
Hydrogen atoms have a “positive”
charge and oxygen atoms have a
“negative” charge. This makes water
a polar molecule.

4. Polar Molecules –have a positive charge on one end and negative charge on the other. Polar molecules and ionic compounds dissolve best in water because they are attracted to the ends of water molecules with the opposite charge.
Water is a polar molecule!
Since opposite electrical charges are attracted to each other, water molecules tend to “stick” together.

5. Ionic compounds - are compounds made up of ions
Ionic compounds - are compounds made up of ions. These ions are atoms that have a positive or negative charge. Salt (Na+Cl-) is an ionic compound and dissolves in water because each atom has a charge.

6. Nonpolar Molecules – do not dissolve well in water because the water molecules are more attracted to each other than the nonpolar molecule; nonpolar molecules do not have an electrical charge; nonpolar substances dissolve in oil

7. Polar
Compounds/Ionic
Compounds

8. II. Universal Solvent Water is capable of dissolving a variety
of different substances, which is why it
is such a good solvent. Water is
called the "universal solvent"
because it dissolves more substances
than any other liquid. Because these
substances can dissolve in water, they
can more easily move into and out of
cells.

9. III. Properties of Water
1. high specific heat– water heats slowly and retains heat longer than most substances; this allows the temperature of water to remain relatively constant

10. Why does water not overheat?
Water heats slowly and can absorb
a lot of heat with only a small
increase in temperature
Water can retain heat for longer
periods of time so
temperatures don’t
drop as quickly
Why does water not freeze?

11.  IF water tends to overheat in the
body, cells maintain homeostasis
by releasing excess heat through
water evaporation = sweating.

12. 2. cohesion – means water
molecules stick to each other.
This attraction between water
molecules causes a condition
known as surface tension. Surface
tension prevents the surface of
water from breaking easily

13. 3. adhesion – means water molecules stick to other materials;
this process creates what is known as capillary action; it allow water to move up the roots & stems of plants against the pull of gravity

14. acids – a solution that has an excess of H+ (hydrogen) ions
III. Acids and Bases
H2O H OH-
( HOH ) hydrogen ion hydroxide ion
acids – a solution that has an excess of
H+ (hydrogen) ions
base – a solution that has an excess of
OH- (hydroxide) ions

15. PH Scale: pH – potential of hydrogen; it measures the hydrogen ion
concentration in a liquid

16. EX: A pH of 4 is how much more
/Basic
/Basic
Each whole number on the pH scale
represents a factor of 10.
EX: A pH of 4 is how much more
acidic than a pH of 6?
A pH of 2 is how much more
acidic than a pH of 5?
100
1000