Deck 4: Water and Ocean Structure

Question 1

The amount of dissolved oxygen that seawater can hold in solution will be greater in .

A) colder water
B) warmer water
C) water with a higher salinity
D) water with lower pressure and density

Answer 1

A

Question 2

Eighty calories of heat energy must be removed per gram of pure water at 0°C to form ice. This represents water's .

A) latent heat of evaporation
B) latent heat of fusion
C) sensible heat
D) temperature

Answer 2

B

Question 3

Residence time is the .

A) same for all elements in the ocean
B) average length of time an element spends in the ocean
C) length of time it takes an element to dissolve in the ocean
D) same as mixing time

Answer 3

B

Question 4

The ocean appears to be in because the proportion and amounts of its dissolved salts per unit volume are nearly constant.

A) constant chemical flux
B) acid-base balance
C) thermal inertia
D) chemical equilibrium

Question 5

The hydrogen bonds of water molecules account for which of the following?

A) Water can cause surface tension and wetting.
B) Water has a long residence time in the atmosphere .
C) Water has a low boiling point.
D) Water has a low heat capacity.

Question 6

Oxygen enters seawater .

A) through the respiration of animals
B) as a byproduct of photosynthesis and diffusion from the atmosphere
C) as a result of decomposition of plant and animal remains
D) through the oxidation of metal ions in seawater

Question 7

If the ocean's water evaporated completely leaving its salts behind, what would the dried residue look like?

A) It would cover the entire planet with an even layer 45 meters thick.
B) It would evaporate into the air with the water.
C) It would leave a thin layer of salts at the bottom of the ocean basin.
D) Approximately 35% of the Earth would be covered with salt.

Question 8

As carbon dioxide enters the ocean, it .

A) is used by animals for respiration
B) bonds to water molecules to increase the salinity of the ocean
C) forms a carbonic acid
D) becomes a product of photosynthesis

Question 9

The term "salinity" refers to the total quantity of .

A) dissolved inorganic solids in water
B) sodium chloride dissolved in the ocean
C) chlorine in 1 kilogram of water
D) chloride ions in ocean water

Question 10

At the present time, the salinity of the ocean seems to be .

A) increasing due to evaporation as the Earth warms up
B) decreasing due to several years of excessive rainfall
C) increasing due to pollution
D) in chemical equilibrium, where ions are added to the ocean at the same rate as they are being removed

Question 11

What is the average residence time water stays in the ocean?

A) about 4,100 years
B) only 9 days
C) forever
D) approximately 3 million years

Question 12

Which of the following statements about pH is true?

A) The pH scale measures the concentration of hydrogen ions in a solution.
B) A pH of 3 is alkaline, a pH of 10 is acid.
C) An acid is a substance that combines with a hydrogen in solution.
D) On average, the pH of the ocean is moderately acidic.

Question 13

The property of water that accounts for the ability of liquid water to absorb large amounts of heat and change relatively little in temperature is called .

A) high heat capacity
B) latent heat of evaporation
C) latent heat of fusion
D) freezing coefficient

Question 14

Heat can be carried to the polar regions .

A) in ocean currents from the tropics
B) in the circumpolar ocean current
C) as water is transported away from the poles
D) as water is transported toward lower latitudes

Question 15

The hydrogen atoms in a water molecule tend to bond to .

A) each other
B) oxygen atoms of another water molecule
C) hydrogen atoms of another water molecule
D) all positively charged ions

Question 16

The components of ocean water whose quantities are less than 1 part per million (ppm) are considered .

A) excess volatiles
B) minor constituents
C) major constituents
D) trace elements

Question 17

What type of bond enables water molecules to stick together?

A) covalent bond
B) molecular bond
C) hydrogen bond
D) atomic bond

Question 18

About what percentage does water expand when it freezes?

A) 90%
B) 9.0%
C) 0.9%
D) 0.0%

Question 19

The two most abundant elements (ions) dissolved in seawater are .

A) fluorine and iodine
B) gold and silver
C) bromine and boron
D) sodium and chloride

Question 20

The average salinity of the world ocean is about .

A) 52%
B) 35%
C) 21.5%
D) 3.5%

Question 21

The geometry of the covalent bonds shared by the hydrogen atoms and oxygen atom in a water molecule account for its polarity.

Question 22

Red light is able to penetrate seawater the deepest.

Question 23

The salinity of seawater is a measure of the amount of sodium and chloride in a water sample.

Question 24

Which of the following statements is true regarding sound in the ocean?

A) Sound is scattered as it bounces off suspended particles in the water.
B) Sound intensity increases as it moves through the ocean because of absorption.
C) The speed of sound in the ocean is ten times less than the speed of sound in air.
D) The speed of sound in the ocean decreases as temperature increases.

Question 25

The thin layer of lighted water near the surface of the ocean is called the .

A) SOFAR layer
B) photic zone
C) aphotic zone
D) pycnocline

Question 26

As carbon dioxide dissolves at the surface of the ocean, it combines chemically to form a weak acid called carbonic acid.

Question 27

A zone in which the ocean's salinity changes rapidly with increasing depth is called .

A) halocline
B) thermocline
C) pycnocline
D) metacline

Question 28

The most precise way to calculate the salinity of seawater is to evaporate a known weight of seawater and weigh the residue.

Question 29

The deepest thermoclines can be found .

A) in temperate zones
B) in Antarctica
C) in the tropics
D) anywhere, depending on water salinity

Question 30

Which region of the ocean generally lacks a thermocline?

A) tropical region
B) temperate region
C) sub-tropical region
D) polar region

Question 31

Frozen water is more dense than liquid water.

Question 32

The amount of heat transported by water vapor in the atmosphere is greater than the amount of heat transported by ocean currents.

Question 33

The density of seawater will increase when .

A) the temperature increases
B) the salinity decreases
C) the salinity increases
D) dissolved gases increase

Question 34

The wavelengths of light that penetrate deepest into the ocean are .

A) red and violet
B) red and yellow
C) blue and red
D) green and blue

Question 35

What is the speed of sound in seawater of average salinity at the surface?

A) the same as the speed of light in the same conditions
B) approximately 1,000 feet per second
C) about 1,500 meters per second
D) twice the speed of sound in air

Question 36

The pycnocline can occur at the same range of depths as a halocline.

Question 37

Heat and temperature both measure random vibrations of an atom or a molecule.

Question 38

The bending of light or sound waves is referred to as .

A) reflection
B) refraction
C) absorption
D) transmission

Question 39

The ocean is stratified with respect to .

A) pH and light transmission
B) temperature and salinity
C) the amount of dissolved oxygen
D) the amount of dissolved carbon dioxide

Question 40

The density of seawater is affected by both temperature and salinity.

Question 41

The tendency for a substance to resist change in temperature with the gain or loss of heat energy is called .

A) latent heat
B) temperature
C) heat capacity
D) thermal inertia

Question 42

Where do dense water masses form?

A) near polar continental shelves
B) along the equatorial zone
C) in enclosed basins where river runoff is great
D) along active continental margins

Question 43

Which of the following contains more heat?

A) a pot of boiling water
B) a warm Jacuzzi
C) a room temperature swimming pool
D) the Pacific Ocean

Question 44

River water contributes which ions to the ocean?

A) carbon dioxide and oxygen
B) hydrogen and oxygen
C) calcium and bicarbonate ions
D) nitrogen and carbon dioxide

Question 45

What processes are responsible for the ocean's salinity?

A) weathering and evaporation
B) weathering and outgassing
C) evaporation and outgassing
D) condensation and evaporation

Question 46

Which statement best reflects global temperatures with respect to San Francisco, California and  Norfolk, Virginia, two cities that lie along the same latitude?

A) San Francisco is warmer in the winter and cooler in the summer.
B) Norfolk is warmer in the winter and cooler in the summer.
C) San Francisco and Norfolk have nearly identical temperatures all season long.
D) San Francisco is cooler in the winter and warmer in the summer.

Question 47

Describe how carbon dioxide acts as a buffer in seawater.

Question 48

Seawater is even though dissolved CO₂ forms into a carbonic acid when combined with water.

A) neutral with a pH of 7
B) a strong acid
C) slightly acidic
D) slightly alkaline

Question 49

Carbon dioxide combines chemically with water to form a(n) .

A) weak acid
B) weak base
C) strong base
D) strong acid

Question 50

Sound can travel for much greater distances through water than light waves can before being absorbed because .

A) Sound waves continue to travel until something physically stops it.
B) Sound waves pick up speed the longer it travels.
C) Sound waves get absorbed and then retransmitted through the ocean every 50 feet allowing it to bounce faster than light waves.
D) Sound waves travel through water more efficiently than light waves.

Question 51

How does water dissolve sodium chloride (NaCl)?

A) Water molecules neutralize sodium ions (Na⁺) and chloride ions (Cl^-).
B) The polarity of water causes the sodium ion (Na⁺) to separate from the chloride ion (Cl^-).
C) When seawater evaporates, its ionic components combine to dissolve table salt.
D) Water molecules expand causing sodium ions (Na⁺) and chloride ions (Cl^-) to decompose.

Question 52

Describe the distribution of oxygen in the ocean from the surface to the deep sea.

Question 53

How much more carbon dioxide can water hold than nitrogen or oxygen at saturation?

A) 50% more
B) 1,000 times more
C) twice as much
D) W ater cannot hold more carbon dioxide than nitrogen.

Question 54

Water behaves like a(n) , which prevents broad swings of pH.

A) acid
B) alkaline
C) polar molecule
D) buffer

Question 55

What is meant by the mixing time of the ocean?

Question 56

Describe the factors that affect the distance and the rate at which sound travels in the ocean. Would you expect sound to travel faster through warm or cold water? Shallow or deep? Why?

Question 57

When liquid water gets below 4°C, it .

A) forms a gas by breaking all of its hydrogen bonds
B) behaves like all other liquids and increases in density
C) begins to decrease in density by expanding
D) compresses its molecular structure and becomes more saline

Question 58

The of the ocean absorbs nearly all the infrared radiation that reaches the ocean surface.

A) upper 300 meters
B) lower 100 feet
C) first meter (3.3 feet)
D) top 1 foot

Question 59

Explain at least three processes that happen to light from the sun as it reaches the surface of the ocean.

Question 60

Which property gives water an unusually high surface tension resulting in a surface "skin" capable of supporting small objects?

A) wetting
B) adhesion
C) high heat capacity
D) cohesion

Question 61

Why does the concentration of dissolved oxygen decreases with depth and carbon dioxide increases with depth?

Question 62

Water resists rising in temperature as heat is added, or falling in temperature when heat is removed.

Question 63

Sound intensity increases as it travels through seawater because of spreading, scattering, and absorption.

Question 64

Why does ice float and why is this important for life in our ocean?

Question 65

How does the hydrogen bonds of water influence the physical properties of the ocean?

Question 66

Because CO₂ dissolves readily in the ocean, it forms a carbonic acid making the average pH of the ocean slightly acidic.

Question 67

Cold water can dissolve more CO₂ than warm water.

Question 68

How much water is on Earth and how does it circulate between the ocean, the atmosphere, and the land?

Question 69

Earth's poles have a deficiency of heat, and the equatorial region has an excess of heat. Why don't the polar regions freeze solid and the equatorial region boil over?

Question 70

When a hydrogen atom (the positive end) in one water molecule is attracted to the oxygen atom (the negative end) of an adjacent water molecule, a covalent bond forms.