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An Introduction to the World's Oceans, 10/e
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The Chemistry of Seawater

Multiple Choice Quiz



1

The removal of ions and molecules from sea water through adherence to a clay particle is termed:
A)absorption.
B)coagulation.
C)adsorption.
D)weathering.
2

Which of the following statements on ocean salinity is not correct?
A)Average salinity is 35 percent.
B)There are, on average, 35g of dissolved salt in every kg of seawater.
C)Salinity of ocean surface water is associated with latitude.
D)Salinities will be lower in areas of high precipitation.
3

Select the ion which is not a major constituent of seawater.
A)sodium
B)chloride
C)iodine
D)calcium
4

Which of the following is not a trace element in sea water?
A)nickel
B)manganese
C)titanium
D)boron
5

Which of the following is not a mechanism for regulating the ocean's salt balance?
A)river discharge
B)sea spray
C)hydrothermal vent activity
D)All of the above are mechanisms.
6

Which of the following statements on the abundance of salts is not correct?
A)The average time that a substance remains in solution is measured by its half-life.
B)Aluminum remains in solution for only short periods of time relative to other ions.
C)Sodium is very soluble and will remain in solution for very long periods of time.
D)Calcium is removed quickly from solution to form shells for organisms.
7

The principle of constant proportion:
A)applies to only the trace elements.
B)can only be applied near river mouths.
C)states that the ratio of major ions does not change with salinity.
D)is different at the ocean bottom than on the surface.
8

The following method is not used to accurately determine the salinity of seawater.
A)electrical conductivity
B)chloride concentration
C)light refraction
D)taste
9

Which of the following describes the saturation values of a gas?
A)Temperature, salinity, and pressure do not affect saturation value.
B)If the temperature increases, the saturation value increases.
C)As pressure increases, saturation value decreases.
D)Decreasing the temperature increases the saturation value.
10

The depth that represents equilibrium between oxygen and carbon dioxide production is termed the ____________ depth.
A)equilibrium
B)compensation
C)decomposition
D)anaerobic
11

Which of the following statements about the distribution of gases is not correct?
A)Plants produce oxygen through photosynthesis at all depths.
B)Oxygen values of quiet surface waters may become supersaturated.
C)Anoxic conditions may occur on the floor of deep basins.
D)Carbon dioxide levels at the surface are typically very low because of photosynthesis.
12

The concentration of this ion determines the pH of water.
A)CO32-
B)Ca2+
C)HCO3-
D)H+
13

Carbon dioxide and water combine to form:
A)CO32-.
B)Ca2+.
C)H2CO3.
D)H+.
14

Research on ice cores recovered in Greenland and Antarctica have revealed all but which of the following?
A)Carbon dioxide concentrations in the atmosphere dropped rapidly at the end of the last ice age.
B)Volcanic dust trapped in the ice reveals when and where eruptions occurred.
C)Pollution from the ancient Greeks and Romans reached Greenland.
D)Climate changes may occur very rapidly.
15

The rate at which the oceans absorb CO2 is controlled by all but which of the following?
A)presence of calcium and carbonate ions
B)transfer of carbon from CO2 to organic molecules
C)circulation of deep ocean water
D)presence of oxygen
16

Carbon dioxide is not released by which of the following?
A)burning of fossil fuels
B)decay of organic material
C)respiration of organisms
D)production of calcium carbonate by organisms
17

Which of the following statements regarding salt sources is not correct?
A)Water carrying sulfate ions is acidic and helps liberate cations in bedrock.
B)The chemical composition of most rivers mirrors that of the oceans.
C)Water emerging from a hydrothermal vent is more saline than water entering the hydrothermal system.
D)There are large quantities of cations in volcanic rocks.
18

Select the following statement that does not accurately discuss chemical resources of the oceans.
A)Less than 50 percent of the world's table salt is extracted from seawater.
B)Uranium and gold have been found to be economically feasible to extract from ocean water.
C)Sea salt can be extracted in cold climate ponds by freezing sea water to a concentrated brine.
D)The majority of the world's supply of magnesium comes from the sea.
19

Which of the following statements on desalination is not correct?
A)Solar powered stills can produce fresh water, but at a very slow rate.
B)Distillation through boiling water and capturing condensate is energy intensive and expensive.
C)Low salinity water can be desalinated by ion exchange.
D)Solar evaporation does not work because the salt evaporates with the water.
20

The process of reverse osmosis in desalination:
A)is more energy intensive than the evaporative processes.
B)is powered by the natural movement of water from high salinity to low salinity.
C)produces no brines to be disposed of.
D)is replacing older distillation plants in water poor areas.
21

Which of the following is an example of a cation?
A)Na+
B)Cl-
C)NaCl
D)H2
22

Which is not true about the latitudinal variations in seawater salinity?
A)Surface salinity is lower near the equator where precipitation exceeds evaporation.
B)Surface salinity is high near 30oN and 30oS where evaporation exceeds precipitation.
C)Salinity is high at the poles where evaporation is low.
D)Salinity is low in the mid latitudes (60oN and 60oS) where precipitation exceeds evaporation.
23

Arrange the following constituents in seawater in order from highest to lowest concentration:
A)magnesium, sodium, potassium, chloride, sulfate
B)chloride, sodium, sulfate, magnesium, calcium, potassium
C)chloride, sodium, calcium, potassium, magnesium, sulfate
D)magnesium, sodium, calcium, potassium, sulfate
24

Which of the following is not a process that adds salt to the ocean?
A)hydrothermal activities at mid ocean ridges
B)volcanoes
C)river runoff
D)sea spray
25

Which of the following ions has the greatest residence time in the oceans?
A)sodium
B)potassium
C)aluminum
D)calcium
26

Which of the following substance has the lowest pH?
A)coffee
B)seawater
C)hydrochloric acid
D)milk