Water is a polar molecule due to its structure of two hydrogen atoms covalently bonded to one oxygen atom. This polarity allows water to form hydrogen bonds with other water molecules, giving water unique properties. Water's high heat of vaporization and specific heat allow organisms to regulate temperature through evaporative cooling and heat absorption. Water's polarity also makes it an excellent solvent and gives it properties like cohesion, adhesion, and the ability to dissolve ionic compounds.

1. Properties of Water Notes
Honors Biology

2. Water in Living Things

3. Organisms remove excess
heat through water
evaporation, while also
maintaining heat with water.
This allows organisms to
maintain a constant internal
temperature which is one
example ofmaintaining
homeostasis.
One Example of Homeostasis

4. Properties due to Water’s Polarity
1. Versatile solvent
2. Cohesion
Example: surface tension
3. Adhesion
Example: capillary action
4. Specific Heat/Heat Capacity
5. Heat of Vaporization
6. Freezing

5. . The molecular
formula for water is
H2O.
. It consists of 2
hydrogen atoms and
1 oxygen atom.
. Covalent bonds
connect hydrogen
and oxygen.
Structure of the Water Molecule

6. . Water is a polar molecule, meaning that
there is an unequal distribution of
electrons. Let’s look at electronegativity.
.
Oxygen is partially negative, and hydrogen
is partially positive.
Why is Water Polar?

7. . The hydrogen atom from one water molecule bonds
weakly to the oxygen atom of another water molecule
through a hydrogen bond.
What is Hydrogen Bonding?

8. Properties due to Water’s Polarity
1. Versatile solvent
2. Cohesion
Example: surface tension
3. Adhesion
Example: capillary action
4. Specific Heat/Heat Capacity
5. Heat of Vaporization
6. Freezing

9. . Polarity ofthe water molecule means that it can attract
other molecules that are charged or polar.
. Water can also dissociate ionic bonds. NOTE: This is not
a chemical reaction.
.Hydrophilic – molecules that are polar/have a charge
and; therefore, attracted to water
.Hydrophobic – molecules that are nonpolar/don’t
possess a charge and; therefore, are not attracted to water
What is the Versatile Solvent?

10. .
Water is attracted to other water molecules
due to hydrogen bonding.
. The oxygen end ofwater has a negative charge
What is Cohesion?
. The hydrogen end has a positive charge.

11. .
Water is attracted to other substances that are
polar or have charges due to hydrogen
bonding.
.
Capillary action is limited by gravity
What is Adhesion?

12. . Review: What are the common states ofmatter and the
transitions between them?
. High Specific Heat/Heat Capacity - water temperature
changes slowly and holds temperature well.
. Why? Hydrogen bonds require an input of energy to
break therefore requiring more energy for water to
change states ofmatter than non-polar or non-charged
molecules
Specific Heat in Water

13. . High Heat of Vaporization - Water requires a lot of
energy to vaporize. When organisms sweat or dogs pant,
they release a high amount ofheat energy.
. Why? Hydrogen bonds require an input of energy to
break therefore requiring more energy for water to
change states of matter than non-polar or non-charged
molecules
Heat of Vaporization

14. Density Changes
. Water is less dense in solid form - Solid water
molecules form a lattice that is less dense then liquid
water and therefore floats.
. Why? The partial positive hydrogens must face the
partial negative oxygens of adjacent water molecules for
the most stable structure since molecules are not sliding
past one another in a solid.

15. Properties due to Water’s Polarity
1. Versatile solvent
2. Cohesion
Example: surface tension
3. Adhesion
Example: capillary action
4. Specific Heat/Heat Capacity
5. Heat of Vaporization
6. Freezing