Unit 3: Dissolved Oxygen
Water’s the Matter
Post-test
Teacher’s Edition
1.
Fish remove dissolved oxygen from water by using their
(Objective 3; correct – C)
A.
B.
C.
D.
E.
2.
plants
heat
fish
bacteria
dams
The maximum percentage of oxygen in water at 4ºC and 1 atom of pressure is
___________. (Objective 1; correct – E)
A.
B.
C.
D.
E.
5.
forming small bubbles.
bound to hydrogen to form water itself.
bound to carbon in the form of carbon dioxide.
as molecules associated with water molecules.
only in very warm areas.
The amount of dissolved oxygen in water will increase by adding ____________.
(Objective 2; correct – A)
A.
B.
C.
D.
E.
4.
lungs
scales
gills
fins
tails
Oxygen is dissolved in water: (Objective 1; correct – D)
A.
B.
C.
D.
E.
3.
.
21%
5%
1%
0.5%
0.001%
When do aquatic plants contribute the most dissolved oxygen to water?
(Objective 2; correct – B)
A.
B.
C.
D.
E.
during the night
during the day
during periods when plants die
production of oxygen by plants is uniform
plants do not produce oxygen, they consume oxygen
6.
If a pond has an unstable level of dissolved oxygen, the best method of correction
would be
. (Objective 2; correct – D)
A.
B.
C.
D.
E.
7.
One liter of water weighs
A.
B.
C.
D.
E.
8.
. (Objective 1; correct – B)
one pound
one kilogram
one ounce
one milligram
one pint
You are standing on the banks of a large lake where dozens of different kinds of
fish are floating dead on the surface. Which of the following things is most likely
to have occurred? (Objective 3; correct – C)
A.
B.
C.
D.
E.
9.
to add fertilizer to the pond.
to add algae to the pond.
to add fish to the pond.
to pump air into the pond.
to expose the pond to direct sunlight.
Bacteria in the water infected the fish causing them to die.
Nitrates in the water poisoned the fish.
The dissolved oxygen levels dropped below 2 mg/L and the fish
suffocated.
The fish ate algae and died from toxins produced by the algae.
The temperature of the lake was too low for reproduction, so the fish could
not breed and died of advanced age.
When water is rapidly moving, like in white water rapids, the turbulence
the surface area and
the amount of oxygen dissolved in the
water. (Objective 2; correct – C)
A.
B.
C.
D.
E.
decreases; decreases
does not effect; increases
increases; increases
decreases; does not effect
decreases; increases
10.
In general, which of the following best describes the effects that dams have on
dissolved oxygen and water quality? (Objective 2; correct – C)
A.
B.
C.
D.
E.
11.
Addition of fertilizer to rivers and streams often results in: (Objective 2; correct –
B).
A.
B.
C.
D.
E.
12.
Dams increase dissolved oxygen by slowing the flow of rivers and
warming the water.
Dams have little or no impact on dissolved oxygen in water.
Dams decrease dissolved oxygen by decreasing aeration and slowing flow.
Dams have devastating effects on the aquatic life behind the dams.
Dams are beneficial to the aquatic life behind them.
an increase in the amount of dissolved oxygen in the water.
an overgrowth of aquatic plants and algae.
an overgrowth of fish and other aquatic organisms.
a complete depletion of oxygen due to binding of oxygen by fertilizer.
an increase in mutations in fish.
You are serving as a research scientist with the Environmental Protection Agency.
You are monitoring the health of rivers in an area by examining the amount of
oxygen dissolved in the water. In an effort to work with the local industries, you
ask companies along these rivers to collect samples and determine the amount of
oxygen dissolved in the samples. You receive the following results.
River
Apple River
Big River
Chattanooga River
Durham River
East River
Company
Apple Sewage Treatment Plant
Big River Golf Course
Chattanooga Dam and Electric Plant
Durham Fertilizer Plant
East River Sawmill
Dissolved oxygen
6 mg/dL
9 mg/dL
14 mg/dL
10 mg/dL
4 mg/dL
You note one value that causes you some alarm, and you immediately alert your
boss and tell her that you suspect one company is causing problems. Who do you
suspect and why? (Objective 3; correct – C)
A.
B.
C.
D.
E.
Apple Sewage Treatment; the levels of dissolved oxygen are too low
considering the sewage that is probably getting in the water.
Big River Golf Course; the levels of dissolved oxygen are too high for the
amount fertilizer that is probably entering the water.
Chattanooga Dam and Electric Plant; the levels of dissolved oxygen are
impossible to obtain under normal circumstances.
Durham Fertilizer Plant; the levels of dissolved oxygen are too high for
the amount of waste that is probably entering the water.
East River Sawmill; the levels of dissolved oxygen are impossible to
obtain under normal circumstances.