Oceanography Chapter 5 & 6.1

The depth at which calcite dissolves rapidly in the ocean is called the __________.

calcite compensation depth or CCD

Carbon dioxide (CO2) combines with water (H2O) to form __________.

carbonic acid (H2CO3)

Latent heat is the quantity of heat gained or lost as a substance undergoes a:

change in state

bonds that involve the sharing of electrons between atoms

covalent bonds

In regions with low rates of precipitation and high rates of evaporation, the halocline will __________.

decrease in salinity with depth The average salinity in the deep sea is 35 ppt. Evaporation increases salinity above average in surface waters, so deeper waters would be expected to have lower salinity.

a pycnocline is a layer of rapidly changing __________

density

As the salinity of seawater increases, its:

density increases.

All the following are methods used to desalinate water

electrolysis. reverse osmosis. freeze separation. distillation.

negatively charged subatomic particles that orbit an atomic nucleus

electrons

All the following processes decrease the salinity of water except :

evaporation

change in state from liquid to gas

evaporation

We would expect the salinity of surface waters to be higher in regions where __________.

evaporation is much greater than precipitation

The primary difficulty that must be overcome in the use of desalination plants to provide fresh water is __________.

the high cost of energy involved Both distillation and reverse osmosis methods have high energy requirements. That makes them most practical in countries where water is scarce and oil is cheap, such as in the Middle East.

The transfer of water between the atmosphere, the oceans, and the continents is known as the:

the hydrologic cycle

Of the following statements about the pH of seawater, which is/are true?

The pH of seawater averages about 8.1 and ranges from about 8.0 to 8.3. Additional carbon dioxide from the atmosphere is getting into the ocean, overwhelming the natural carbonate buffering system. In a natural state, the carbonate buffering system protects the ocean from getting too acidic or too alkaline.

bonds that hold adjacent water molecules together

hydrogen bonds hold water molecules together

Pure water reaches its maximum density at about________, which is a density value higher than at the freezing/melting point.

4ºC

What is the hydrologic cycle?

The hydrologic cycle describes how liquid and gaseous water move between the ocean, atmosphere, and land.

How much of Earth's surface water exists in the oceans?

Almost all of Earth's surface water exists in the oceans.

CCD starts at

around 4500 meters, is where the combination of temperature and pressure result in more acidic water.

change in state from gas to liquid

condensation

river input

decreases seawater salinity

evaporation

increases seawater salinity

pH stands for

power of Hydrogen

Where is most of Earth's freshwater found?

as ice at Earth's surface

basic building blocks of all matter

atom

change in state from solid to gas

sublimation

Remember that a thermocline is a layer of rapidly changing ___________

temperature

The density (mass per volume) of most liquids increases as the __________ is lowered.

temperature

The states of matter in which water exists is primarily determined by:

temperature

The average salinity of typical seawater is:

3.5%

Of the following statements about seawater properties in high and low latitudes, which is/are true?

There is a thermocline in low latitudes. There is a halocline in low latitudes. There is a halocline in high latitudes. There is a pycnocline in low latitudes.

What is the most abundant ion in seawater?

Chloride, which is more abundant than sodium because sources include both dissolved salts and submarine volcanic vents.

There is a general trend of decreasing pH with increasing water depth in the ocean. What is the cause of this pattern?

Deeper, colder ocean water contains more dissolved carbon dioxide, which causes the pH to be lower. As CO2 dissolves, it increases the amount of carbonic acid in the water, thus making it more acidic.

Which process in the hydrologic cycle is most effective at increasing ocean salinity on a global scale?

Evaporation occurs over broad expanses of the ocean, especially in the subtropics, which removes water molecules and makes the ocean water saltier.

T/F: In distillation, saltwater is highly pressurized to drive water molecules through a membrane to remove salts.

FALSE

T/F: Processes that decrease seawater salinity include evaporation and sea ice formation.

FALSE

T/F: At high latitudes, abundant precipitation and runoff from melting of freshwater icebergs both increase salinity.

FALSE, it does not increase salinity

T/F: As a whole, the pH of the ocean is slightly acidic.

FALSE, it is alkaline

T/F: The density of seawater is slightly lower than the density pure water.

FALSE, pure water is more dense

T/F: Greater temperature fluctuations are seen in coastal areas due to the marine effect.

FALSE, the marine effect is not responsible for temperature fluctuations

T/F: Water can pile up higher than the edge of a container due to its low surface tension.

FALSE, water has high surface tension

The ion in sea water that serves as a buffer is:

HCO3-

If you were an explorer stranded in the Arctic Ocean, what method(s) could you use for creating fresh drinking water?

Heat sea ice that formed a long time ago. Boil seawater; catch and condense the water vapor. Take seawater and freeze and melt it several times to purify it. Catch and melt fresh falling snow. Old sea ice that formed a long time ago turns out to be very pure. As time goes on, sea ice tends to purify itself by isolating and removing the trapped solids. This is the process of freeze separation, which is an effective method of purifying seawater. This is the process of distillation, which is an effective method of purifying seawater.

What causes water's density to decrease when it freezes?

Hydrogen bonds which form in an orderly manner with adjacent water molecules when frozen.

Water's latent heat and change in state has qualities such as:

In the vapor state, there are no weak (hydrogen) bonds between water molecules. Latent heat allows water to transfer energy from one place to another. When water evaporates, its latent heat of evaporation absorbs heat. In the solid state, all water molecules are connected by weak (hydrogen) bonds. When water vapor condenses and forms a liquid, its latent heat of condensation releases heat to the environment; this is what powers hurricanes.

How does water get from the oceans onto land?

Ocean water evaporates to form gaseous water and moves into the atmosphere, where it condenses into liquid water and falls out of the atmosphere to land as rain.

What would happen to the oceans if surface runoff and groundwater flow did NOT occur?

Oceans would become smaller

T/F: Precipitation, runoff, melting icebergs, and sea ice formation all decrease salinity.

TRUE

T/F: Hydrogen bonds between water molecules are responsible for the unusual chemical and physical properties of water.

TRUE, Hydrogen is responsible for water's unusual properties

T/F: Evaporation causes cooling in the liquid left behind.

TRUE, evaporation causes cooling in the liquid left behind.

Deep-ocean water contains more carbon dioxide than surface water because deep water is colder and has the ability to dissolve more gases.

TRUE, there is more CO2 in deep ocean water.

T/F: The density of seawater is affected by salinity and temperature.

TRUE, these do affect seawater's density

T/F: Water molecules exhibit strong cohesion.

TRUE, they do exhibit strong cohesion.

T/F: The heat capacity of liquid water is 1 calorie per gram per degree C.

TRUE, water's heat capacity is 1 calorie per gram per degree Celsius

Calorie

The amount of energy that is necessary to raise the temperature of one gram of water by one degree C

Why do ionic compounds dissolve readily in water?

The electrostatic attraction between ions is weakened by the polarity of water.

What increases the salinity of seawater?

The formation of sea ice removes water molecules plus about 30% of the salts, so it increases the salinity of the remaining seawater.

Which requires the greatest amount of heat energy?

Vaporizing one gram of water which requires the input of 540 calories.

Of the following statements about the density of freshwater and the formation of ice, which is/are true?

Water at 2ºC is less dense than it is at 4ºC. Water's maximum density is at 4ºC. As the temperature of water decreases from 4ºC to 0ºC, its density decreases. Ice is less dense than liquid water, which is why ice floats.

What is caused by water's odd geometry?

Water molecules form hydrogen bonds. Water molecules have polarity. Water has cohesion and surface tension. Water has the ability to dissolve just about anything. Snowflakes form six-sided crystals.

layer of the ocean that experiences a rapid change in salinity with depth

halocline

Which property of water causes coastal communities to have only moderate differences in daily highs and lows when compared to inland communities?

high heat capacity

The pH scale is a measure of the __________ ion concentration of a solution.

hydrogen ion

sea ice formation

increases seawater salinity too

charged atoms due to the gain or loss of one or more electrons

ions

The surface tension of water:

is relatively high

Oil and water do not mix, even when shaken is because

oil molecules are non-polar and are not attracted to the poles of the water molecules.

All the following are methods used to desalinate water except :

osmosis

layer of the ocean that experiences a rapid change in density with depth

pycnocline

a halocline is a layer of rapidly changing ________

salinity

The pH of surface seawater usually has a value of around 8.0. That means the water is __________.

slightly basic, or alkaline because it is above 7.0 on the pH scale