Section #: 15.2
Seawater
Practice Test
1.
What layer is shown right above the thermocline (around 1000 meters deep) in the graph?
a.
bottom layer
b.
top layer
c.
surface layer
d.
thermal layer
Hint
2.
What is one source of sodium ions found in the ocean?
a.
volcanic gases
b.
ultraviolet radiation
c.
evaporation
d.
the shells of marine organisms
Hint
3.
The salinity of seawater is __________ over geologic time.
a.
always changing
b.
decreasing
c.
increasing
d.
constant
Hint
4.
What is the densest and coldest water mass of all Earth's oceans?
a.
Antarctic bottom water
b.
Gulf Stream
c.
Antarctic intermediate water
d.
North Atlantic deep water
Hint
5.
What is the cause of ocean layering?
a.
polar ice caps
b.
evaporation
c.
currents
d.
density differences
Hint
6.
In the graph, what is the sharp drop in temperature from about 20° to about 7° called?
a.
the trophocline
b.
the thermocline
c.
the temperaturcline
d.
the tomocline
Hint
7.
Which element is not an ion found in ocean water?
a.
Na
b.
K
c.
Cl
d.
Ni
Hint
8.
What is the average salinity of ocean water?
a.
35 ppt
b.
37 percent
c.
37 ppt
d.
30 ppt
Hint
9.
According to the graph, which salt is the most abundant in sea water?
sodium chloride (NaCl)
23.48 g
magnesium chloride (MgCl
2
)
4.98 g
sodium sulphate(Na
2
SO
4
)
3.92 g
calcium chloride (CaCl
2
)
1.10 g
potassium chloride (KCl )
0.66 g
sodium nicarbonate (NaHCO
3
)
0.19 g
potassium bromide (KBr)
0.10 g
a.
sodium chloride
b.
magnesium chloride
c.
sodium sulfate
d.
potassium bromide
Hint
10.
The density of seawater is dependent on __________.
a.
temperature and currents
b.
salinity only
c.
temperature only
d.
salinity and temperature
Hint
11.
What is the thermocline?
a.
a transitional layer in the ocean where temperature decreases rapidly with depth
b.
a change in salinity with depth
c.
a layer of cold water in the ocean
d.
the formation of cold water coming from Antarctica
Hint
12.
Why are salinities lower than average in some areas close to the equator?
a.
stronger winds
b.
abundant precipitation
c.
rapid evaporation
d.
larger clouds
Hint
