Unit 4 Test
Multiple Choice
Identify the choice that best completes the statement or answers the question.
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1. Water can mingle with other elements because it is a:
a. heating agent.
b. solvent.
c. solid.
d. vapor.
e. nonpolar molecule.
2. The charge of a water molecule is considered:
a. polar.
b. positive.
c. negative.
d. neutral.
e. nonpolar.
3. The polarity of a water molecule is due to:
a. the greater number of hydrogen atoms relative to oxygen.
b. the uneven attraction of electrons to the oxygen atom.
c. the uneven attraction of electrons to the hydrogen atoms.
d. the uneven attraction of protons to the oxygen atom.
e. the number of neutrons in the nucleus.
4. The unique attractive forces that keep molecules of water together are called:
a. strong forces.
b. adhesion.
c. hydrogen bonds.
d. cohesion.
e. weak nuclear forces.
5. Hydrogen bonds are the result of attraction between:
a. the H of one water molecule and the H of another water molecule.
b. the two H atoms of the same water molecule.
c. the H and O of the same water molecule.
d. the H of one water molecule and the O of another water molecule.
e. the O of one water molecule and the O of another water molecule.
6. The property of water whereby molecules tend to stick to one another is called:
a. cohesion.
b. polarity.
c. dissolving ability.
d. adhesion.
e. viscosity.
7. Surface tension allows water molecules to do all the following except:
a. transmit light energy.
b. resist evaporation.
c. form a tight surface layer.
d. support small organisms.
e. resist evaporation and transmit light energy.
8. Hydrogen forces have high attractive forces that allow water to have a high:
a. strength.
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b. solubility.
c. freezing point.
d. boiling point.
e. rate of evaporation.
Water is unique because its solid phase is ____ the liquid phase.
a. denser than
b. similar to
c. less dense than
d. Less dense than or similar to
e. None of these.
Which low energy light wave length is quickly absorbed by water?
a. Red.
b. Orange.
c. Yellow.
d. Green.
e. Red, orange, and yellow.
Which high energy light wave length can penetrate sea water the deepest?
a. Blue.
b. Green.
c. Violet.
d. Red.
e. Blue, green, and violet.
In most clear waters, 1% of surface light can penetrate to:
a. 10 m.
b. 20 m.
c. 50 m.
d. 75 m.
e. 100 m.
You are SCUBA diving with a friend, who is wearing a red and purple wetsuit. You both descend and
conduct your underwater research at 30 m. What color(s) does her wetsuit appear at this depth?
a. Black and dark blue.
b. Dark blue and purple.
c. Dark green and black.
d. Dark red and black.
e. Dark green and dark blue.
Light that is absorbed by water is converted to:
a. short wave radiation.
b. long wave radiation.
c. heat.
d. mass.
e. green light.
The pH scale is a measure of:
a. how many degrees a professor has.
b. the temperature of water.
c. concentration of hydrogen ion in a volume of solution.
d. concentration of hydroxide ions in a volume of solution.
e. None of these.
The pH of seawater is important to living organisms because:
a. it can affect the functioning of enzymes.
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b. it can interfere with metabolism.
c. it can affect growth.
d. All of these.
e. None of these.
A trace element's concentration is less than a part per:
a. thousand.
b. million.
c. billion.
d. trillion.
e. hundred.
Salinity is expressed in parts per:
a. hundred.
b. thousand.
c. ten thousand.
d. hundred thousand.
e. million.
The average salinity of seawater is ____0/0.
a. 35
b. 37
c. 40
d. 45
e. 50
The salinity of seawater at the poles is:
a. high due to evaporation.
b. low due to precipitation.
c. high due to freezing.
d. low due to river input.
e. similar to the open ocean.
The salinity of seawater at the equator is:
a. high due to evaporation.
b. low due to precipitation.
c. high due to freezing.
d. low due to river input.
e. low due to temperature.
Salts are removed from the oceans primarily by:
a. absorption by living organisms.
b. removal by sea spray.
c. evaporation.
d. adsorption onto particles.
e. salt mining.
Gases that are regulated by biological processes include:
a. oxygen.
b. carbon dioxide.
c. argon.
d. oxygen and carbon dioxide.
e. carbon dioxide and argon.
The oxygen minimum layer is found:
a. in the ocean trenches.
b. mid-ocean.
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c. just below the sunlit surface.
d. at the surface.
e. just above the abyssal plain.
In terms of gas solubility in sea water, what is the correct relationship?
a. Carbon dioxide > oxygen > nitrogen.
b. Oxygen > carbon dioxide > nitrogen.
c. Nitrogen > carbon dioxide > oxygen.
d. Carbon dioxide > nitrogen > oxygen.
e. Oxygen > nitrogen > carbon dioxide
Seawater is considered buffered due to the presence of:
a. oxygen ions.
b. nitrogen ions.
c. bicarbonate ions.
d. silicon ions.
e. calcium ions.
The mass of a substance divided by its volume is:
a. heat capacity.
b. surface tension.
c. density.
d. salinity.
e. viscosity.
The two main factors controlling the density of water are:
a. salinity and temperature.
b. salinity and heat capacity.
c. salinity and pH.
d. pH and heat capacity.
e. temperature and pH.
A zone of rapid temperature change is called a(n):
a. pycnocline.
b. thermocline.
c. halocline.
d. isocline.
e. None of these.
The Coriolis effect is:
a. the downwelling of seawater at the equator.
b. the upwelling of seawater at the equator.
c. the apparent deflection of the path of air and water.
d. the reduction of air speed over the ground as one goes from the equator to the poles.
e. None of these.
A common generating force for surface waves in the oceans is:
a. wind.
b. gravity.
c. surface tension.
d. capillary action.
e. undersea tectonic activity.
The designation of winds is referenced from:
a. the direction from which they are coming.
b. the direction towards which they are going.
c. folk lore.
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d. the need to throw horses overboard.
e. the direction in relation to the observer’s path of travel.
Tsunamis are usually:
a. deep-water waves.
b. shallow-water waves.
c. wind waves.
d. capillary waves.
e. the result of winter storms.
A tidal pattern of two equal high and low tides per day is called a:
a. mixed semidiurnal tide.
b. semidiurnal tide.
c. diurnal tide.
d. spring tide.
e. neap tide.
You are on the beach at Corpus Christi, Texas. High tide falls at noon, and the tides are diurnal here.. When
will be the next high tide?
a. 6 pm that evening.
b. 12 hours later, at midnight.
c. 6 am the next morning.
d. Noon the next day.
e. 9 pm that evening.
A falling tide is called a(n):
a. flood tide.
b. spring tide.
c. neap tide.
d. ebb tide.
e. mixed tide.
Short Answer
1. Large bodies of water maintain relatively constant temperatures compared to terrestrial
locations. Why is this so and how is this feature of water important for life?
2. List the most abundant ions in seawater, from most to least abundant.
3. Describe the physical factors involved in the layering of the oceans.
4. Even though seawater continues to dissolve minerals from rocks and new minerals are added
from the interior of the Earth, the salinity of the oceans is not increasing over time. Explain 3
reasons that cause this.
5. Explain why thermohaline circulation (the vertical mixing of the water column due to density
differences) is important for living organisms.
6. Describe the astronomical conditions that give rise to the extreme spring tides and neap tides
during certain periods of the month.
7. Describe the differences and similarities between upwellings and downwellings and why
they are important components to our oceans.
8. Explain how salt from the sea is returned to land.
9. Why do objects appear more blue and green when viewed underwater? Use examples.
10. What is salinity, where did the salt come from, how does the salt remain the same after
billions of years, and how is the salt removed?
11. What are the major gases in seawater and how are they distributed (be specific about CO2
and O2)? What factors contribute to the amount of gas the ocean can hold?
12. What are surface currents and what are four reasons why they are so important?
13. What is the Coriolis Effect and how does it affect currents?