GOAL CHPT. 3:
Develop a conceptual
understanding of how
water contributes to the
fitness of Earth for Life
The Water Planet
The polarity of water
molecules results in
HYDROGEN BONDING (weak inter-molecular bond)
Remember, H2O is a
polar covalent bond
+
+
The polarity of water
molecules results in
HYDROGEN BONDING (weak inter-molecular bond)

•each molecule
can bond to max.
of 4 neighbor

molecules via.
hydrogen bond


The polarity of water
molecules results in
HYDROGEN BONDING (inter-molecular bond)
-weak bond
-constantly
reforming
Properties of Water that
contribute to its importants for
life:
1)Cohesion
*water sticks to water
Properties of Water that
contribute to its importants for
life:
1)Cohesion
AP Bio
1st & 4th period
HOBBY
Room 121
Properties of Water that
contribute to its importants for
life:
2)Adhesion
- (adhesive)
*Water sticks to other
surfaces
Properties of Water that
contribute to its importants for
life:
2)Adhesion
*Water
attracted to
other
surfaces
-
Water transport in trees uses
Cohesion and Adhesion
Properties of Water that
contribute to its importants for
life:
3)
High Surface Tension*Cohesion of water molecules
to eachother at the surface of
the body of water.
Water is difficult to stretch or
break the surface.
Properties of Water that
contribute to its importants for
life: 4) High Specific Heat =
- amount of heat energy
needed to raise 1 g. of a
substance 10C
Properties of Water that
contribute to its importants for
life: 4) High Specific Heat =
It takes “a lot” of heat for
water to increase 1oC
b/c of the hydrogen bonds!!!
- water is able to absorb
heat, without increasing
in temperature, better
than many substances
Compared with most other
substances, water absorbs
FAR MORE HEAT before
it raises 1oC in temp.
b/c the heat first must break the
hydrogen bonds, AND THEN… the
molecules of water can begin to
move!!!
As a result:
*) Water stabilizes temperatures. =
acts as a heat sink
H20 absorbs and stores MUCH heat
from sun & air
Water stabilizes temp. =
For water to increase in temp. water
molecules must be made to move faster… this
requires breaking hydrogen bonds, and
THAT absorbs heat.
therefore:
Water will change
temperature less when
it absorbs or looses an
amount of heat… than
other substances
Water’s moderating effect
on the climate under water
Water is also able to retain
heat better than many
substances (resists cooling)
For water to decrease in temp. water molecules
must be made to move more slowly. This
requires forming hydrogen bonds. The forming
of H-bonds gives off heat (hence counteracting
cooling tendencies as heat is lost from liquid
water)
heat - measure of
total K.Energy of
molecule due to
molecular motion
temp. - measures average
speed of the molecule
Water is also able to retain
heat better than many
substances (resists cooling)
As a result, the air around the cooling water
becomes warm
(remember.. The forming of H-bonds gives off
heat!)
Properties of Water that
contribute to its importants for
life:
*) Heat
of vaporization = high
Amount of energy needed to change a
substance to a gas.
-Water resists evaporating (vaporizing) b/c Hbonds must be broken in order for water to
transition from liquid to the gas state.
Properties of Water that
contribute to its importants for
life:
*) Evaporative
Cooling = high
•evaporative cooling - the molecules
that remain after evaporation are
cooler
The Water that remains
isEvaporative
coolerCooling
“I'm not out there sweating for
three hours every day just to find
out what it feels like to sweat.”
- Michael Jordan
Properties of Water that
contribute to its importants for
life:
5) Less
dense as a solid
than liquid
- Bodies of H2O do
not freeze from
bottom up
Solids and Liquids
Water
Benzene
Floats
Sinks
Stable H-bonds
unstable H-bonds
Properties of Water that
contribute to its importants for
life:
6) Water is versatile Solvent
Ability of Water to dissolve some
substances and not others
H2O dissolves substances to which it can readily
H-bond - - attracted to b/c the substance has a
full or partial charge.
Properties of Water that
contribute to its importants for
life:
6) Water
is versatile Solvent
Hydrophilic - ionic & polar compnds
-loves water ex. salt
Properties of Water that
contribute to its importants for
life:
6) Water
is versatile Solvent
Hydrophobic - nonpolar compnds
-repels water ex. cell membrane/lipids
Properties of Water that
contribute to its importants for
life:
8) Dissociation of Water Molecules
p+
e+
H 3O+
water can sometimes split
into two ions
OH-
Properties of Water that
contribute to its importants for
life:
8) Dissociation of Water Molecules
p+
e+
H 3O+
hydronium
OHhydroxide
water can sometimes split into two ions b/c
the attractive force of the oxygen is so great
pH
p = power (percentage) of hydronium
(hydrogen ions)
This is what pH measures
in d. H2O, THIS occurring is super
RARE!!!!
p+
e+
H 3O+
hydronium
OHhydroxide
e-
p+
+
H 3O+
OH-
pure H20 has an (almost) equal amount of
each
pH measures the concentration of
H+
PH = -LOG [H+]
(CONCENTRATION OF H+
IONS)
PH = -LOG OF 1 IN 10,000,000
CHANCE OF THE DISSOCIATION
HAPPENING IN D. H2O
pH = -log [1X 10-7] put that in
your calculator… and what do
you get?????
pH = -log [1X 10-7] put that in
your calculator… and what do
you get?????
You get 7
pH measures the concentration of
H+
ex. HCl
(everyone knows this ACID)
Put it in water… what will
happen?
H+
Cl-
The concentrationof H+ in the
water is now much more
Now, we could say that the
concentration of H+ is no
longer 1 in 10,000,000 …
It could be 1 in 100
pH = - log [1 in 100]
pH = - log [1 X 10-2]
Hydrogen ion = acid ->increases H+
Hydroxide ion = base -> reduces H+
ex. NaOH
(everyone knows this BASE)
Put it in water… what will
happen?
Na+
OH-
What will those H+ ions that are
broken off of water do?
They will combine to the
OHNa+
OHH+
H20
For a neutral solution:
[H+] is 1in 10,000,000
or - log 10-7
or - (-7)
or 7
+
H
OH
=10
14
H+= 10-6
OH-= 10-8
H+= 10-8
OH-= 10-6
Acceptable biological range
Acid
precipitation
normal precipitation
Acid Rain
Acidification of oceans
dissociates
Supposed to
be used for
the animals
Buffers-> Materials that have both
acid and base forms in a solution.
->Minimizes changes in pH
Buffers-> Materials that have both
acid and base forms in a solution.
->Minimizes changes in pH
+
H
->buffer accepts
from the
solution when the solution is too
acidic
ex. Carbonic acid in blood
Buffers-> Materials that have both
acid and base forms in a solution.
->Minimizes changes in pH
->buffer donates H+ to the
solution when the solution is too
basic
In pure water the
concentration of each ion is
10-7 M
 The molecular weight of a substance in
grams.
 One Avogadro’s number of molecules.
6.02 X 1023
One Mole of each
Sugar
Copper Sulfate
Sulfur
Mercury Oxide
Sodium Chloride
Copper
Dr. Otto Warburg discovered a cause of cancer in 1923 and he
received the Nobel Prize in Physiology or Medicine for doing so in
1931.
Dr. Warburg was director of the Kaiser Wilhelm Institute (now
Max Planck Institute) for cell physiology at Berlin. He
investigated the metabolism of tumors and the respiration of
cells, particularly cancer cells.
He discovered, among other things, that cancerous cells can live
and develop, even in the absence of oxygen.
We have made a lot of bad choices and let our daily air and water
become polluted, and this pollution has increasingly been collecting
inside us.
Deprive your cells of enough oxygen for a
long enough period of time and disease will
develop. Dr. Warburg's research has proven
that when a 35% decrease in oxygen is
prevalent, cancer can develop within 48
hours.
This chronic low oxygen condition that we all have causes
our cellular oxygen levels to drop so our blood becomes
more and more polluted. Acidic blood sets the stage for
some diseases. The increasing rates of viral infections and
cancers are not by coincidence.
Our too-low cell oxygen levels encourage toxic buildups
ACIDIC and the growth of anaerobic (can't live in active
oxygen) microbes such as bacteria, viruses, fungi, and
other pathogens inside us and inside our animals and
pets, and in our plants.
Anaerobes and toxicity slowly building up and
overtaking us until we break down are the ultimate cause
of most human, animal, and plant health problems as
well as being the precursors to the whole list of
'incurable' diseases.
Cancerous tissues are acidic, whereas
healthy tissues are alkaline.
Evolutionary advantage
Assists in the survival of
the individual organism… in
turn, prolongs the
longevity of the specie
Emergent Properties of
water…
It has everything to do
with the
H-bond!!
Summary chpt. 3
 Be able to discuss the properties of
water.
 Be able to measure solution
concentrations in Molarity.
 Be able to work pH scale questions.