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. 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 protecting life on Earth from hot lethal temperatures and from freezing

4. Why does water not overheat?
Water 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?

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

6. 2. cohesion – an attraction between
substances of the same kind.
This attraction between water
molecules causes a condition
known as surface tension. Surface
tension prevents the surface of
water from breaking easily

7. 3. adhesion – an attraction between
different substances; adhesion
powers a process called capillary
action; for example, water moving
up the roots & stems of plants

8. 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 (H2O) is considered a polar molecule!
Salt (Na+Cl-) dissolves in water because each atom has a charge.

9. 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

10. Ionic
Compounds/

11. 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

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

13. 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