Water & the Fitness of the Environment
Name_________________________
Date__________________________
Student Objectives:
1. Explain how water supports all life
2. Explain why water is polar and how it affects its properties
3. List and describe the four properties of water
Notes:
Water Supports All Life
Most cells are surrounded by water, and cells consist of about ______________ water.
Three-quarters of the ________________________ is submerged in water. The abundance of water is the
main reason the Earth is _____________________________.
Properties of Water
The polarity of water molecules results in ________________________________. The water molecule is a
______________________________ due to uneven distribution of ___________________________. The
________________________________ of a water molecule have ___________________________________.
Place the correct charges on the polar water molecule below (-) and
(+) showing the positive and negative poles :
Polarity of Water
The ____________________ of water molecules allows them to form
_____________________________ with each other and contributes to
various properties water exhibits.
Four Properties of Water
The four properties of water that contribute to Earth’s fitness for life:
1) ________________________________________________________
2) ________________________________________________________
3) ________________________________________________________
4) ________________________________________________________
Water & the Fitness of the Environment
Name_________________________
Date__________________________
1) Cohesive Behavior: Water molecules exhibit cohesion;
cohesion is the ___________________ of a high
percentage of water molecules to neighboring
___________________. Cohesion is due to
___________________________________. Adhesion is the
hydrogen bonding between water and other
______________________________. Surface Tension is
related to _____________________; it is a measurement of
how hard it is to break the surface of a liquid.
2) Moderation of temperature: Water moderates air temperature by ____________________ heat from
warmer air and ____________________ the stored heat from cooler air. Water can absorb or release a
large amount of heat with only a slight change in its own temperature.
Heat & Temperature
a. __________________________ is the energy of motion
b. __________________________ is a measure of the total amount of kinetic energy due to
molecular motion
c. __________________________ is the measures the intensity of heat due to average kinetic energy
of molecules
d. __________________________ is the amount of heat that must be absorbed or lost for 1 gram of
that substance to change its temperature by 1° C. Water has a high ______________________
relative to other compounds.
3) Expansion upon Freezing: The hydrogen bonds in ice are more “______________” than in liquid water,
making ice less ________________ and able to float.
4) Versatility as a Solvent: Water is a versatile solvent due to its
_____________________. The different regions of the polar water
molecules can interact with ionic compounds called solutes and dissolve
them. An __________________ solution has water as the solvent.
Water & the Fitness of the Environment
Name_________________________
Date__________________________
Skill Building & Application of concepts:
1. In a single molecule of water, the two hydrogen atoms are bonded to a single oxygen atom by
a. Hydrogen bonds
b. Nonpolar covalent bonds
c. Polar covalent bonds
d. Ionic bonds
e. Van der Waals interactions
2. The slight negative charge at one end of one water molecule is attracted to the slight positive
charge of another water molecule. What is this attraction called?
a. A covalent bond
b. A hydrogen bond
c. An ionic bond
d. A hydrophilic bond
e. A hydrophobic bond
3. What determines the cohesiveness of water molecules?
a. Hydrophobic interactions
b. Nonpolar covalent bonds
c. Ionic bonds
d. Hydrogen bonds
e. Both A and C
4. Which of the following is possible due to the high surface tension of water?
a. Lakes don’t freeze solid in winter, despite low temperatures
b. A water strider can walk across the surface of a small pond
c. Organisms resist temperature changes, although they give off heat due to chemical
reactions
d. Water can act as a solvent
e. The ph of water remains exactly neutral
5. What do cohesion, surface tension, and adhesion have in common with reference to water?
a. All increase when temperature increases
b. All are produced by ionic bonding
c. All are properties related to hydrogen bonding
d. All have to do with nonpolar covalent bonds
e. c and d only
Water & the Fitness of the Environment
Name_________________________
Date__________________________
6. Water’s high specific heat is mainly a consequence of the
a. Small size of the water molecules
b. High specific heat of oxygen and hydrogen atoms
c. Absorption and release of heat when hydrogen bonds break and form
d. The fact that water is a poor heat conductor
e. Inability of water to dissipate heat into dry air
7. Ice is lighter and floats in water because it is a crystalline structure in which each water molecule
is bonded to a maximum of four other water molecules by which kind of bond?
a. Ionic
b. Hydrogen
c. Covalent
d. A and C only
e. A, B and C
8. Explain how water supports all life
9. Explain why water is polar and how it affects its properties
10. List and describe the four properties of water