Chapter 6 - Water and Seawater

Major dissolved constituents of seawater have concentrations greater than _____ parts per million (milligrams per kilogram)

100

The average salinity of seawater is about __ PSU.

35

Normal seawater has a pH of approximately

7.5 - 8.1

Roughly _____ percent of the world's water is stored in the oceans.

97.

If four fluids do not mix in a container and their densities are A 1.00, B 1.05, C 1.04, and D 1.07 they will separate into layers in the following order from the bottom to the top:

D, B, C, A

Ocean sediments are transformed to sedimentary rocks by: the precipitation of minerals between individual grains as water is squeezed out. Answers: A.) pressure due to the weight of additional sediments accumulating on top. B.) the high temperatures of volcanic processes near the ridge. C.) the precipitation of minerals between individual grains as water is squeezed out. being eaten by animals and turned into fecal pellets. D.) A and C

D.) A and C A.) pressure due to the weight of additional sediments accumulating on top. and C.) the precipitation of minerals between individual grains as water is squeezed out. being eaten by animals and turned into fecal pellets.

Naturally occurring organic compounds are introduced to seawater by: A. the decay of marine organisms. B. volcanic processes. C. the excretion of waste material by marine animals. D. A and C

D: A.) the decay of marine organisms and C.) the excretion of waste material by marine animals.

Which of the following elements has the shortest residence time in seawater?

Iron

The concentrations of most elements in seawater have remained approximately the same for millions of years because

The concentrations are in a steady state with the inputs of each element being approximately equal to the removal rates.

Which of the following is true? A. The salt content of seawater is high because the sodium and chlorine atoms can form oppositely charged ions that bind the two atoms together rigidly after they have dissolved. B. The salt content of seawater is high because the hydrogen bond between water molecules is very strong. C. The salt content of seawater is high because water molecules are polar and can surround positively charged and negatively charged atoms called ions and allow them to move around freely. D. The salt content of seawater is high because the water molecules neutralize the van der Waals forces between the ions of dissolved compounds.

The salt content of seawater is high because water molecules are polar and can surround positively charged and negatively charged atoms called ions and allow them to move around freely.

Which of the following statements is true? A. The total quantity of water in the oceans is continually increasing as more is added through volcanism and as a result sea level is rising several millimeters per year. B. Water is continuously evaporated from the oceans but the volume of ocean water stays the same because the evaporated water is replaced through volcanism. C. The total quantity of water in the oceans has remained essentially unchanged for many millions of years. D. Fresh water flowing into the oceans from rivers adds to the total amount of water in the oceans and is responsible for continuously but slowly raising sea level for the past several millions of years.

The total quantity of water in the oceans has remained essentially unchanged for many millions of years.

Elements whose atoms have their outermost shell filled with electrons

are inert and do not react chemically with most other elements.

The average concentration of carbon dioxide in seawater is higher than in the atmosphere because

carbon dioxide reacts with water to produce highly soluble carbonate and bicarbonate ions.

Extremely accurate measurements of salinity are important because changes in salinity

cause changes in density.

Oxygen concentration is generally highest in

cold polar surface water.

Which of the following bonds is the strongest?

covalent bond.

Each water molecule consists of two hydrogen atoms and one oxygen atom. The atoms within each water molecule are held together by

covalent bonds.

When fluids are separated into layers each higher layer has a progressively lower

density.

A stably stratified fluid is one in which

each higher layer is lower in density.

The most precise and widely used method of determining salinity is the measurement of the seawater

electrical conductivity.

Elements that are effectively removed from solution in seawater

generally have short residence times.

Fluids form horizontal layers in response to

gravity.

The pH of seawater or other solutions is a measure of the concentration of their _____ ion concentration.

hydrogen

Saturation solubility of gases in seawater increases with

increasing pressure and decreasing temperature.

Atoms that have lost or gained one or more electrons so they have an unequal numbers of protons and electrons are called

ions.

Which of the following is not a major constituent of seawater?

iron

Seawater samples taken from some coastal areas can appear to have a brownish-yellow color due to the high concentration of

organic compounds washed out of mangrove swamps or salt marshes.

Historically, the salinity of seawater was measured in units of

parts per thousand

The nucleus of an atom consists of

positive charge protons and neutral charge neutrons.

One reason that water is a unique compound is because it is the only known substance that is

present in all three states of matter at the surface of Earth.

The arrangement of different fluids in horizontal layers on top of each other is called

stratification.

In deep water below the surface layer of the oceans, the dominant process affecting the concentration of dissolved oxygen concentrations in seawater is

the consumption of oxygen by respiration and decomposition.

The water molecule is a polar molecule because

the electrons are distributed such that the molecule has electrically positive and negative sides.

Atoms are electrically neutral when

the number of protons equals the number of electrons.

The process of hydration occurs when solid substances are dissolved in seawater. This process occurs as a result of

the polar nature of the water molecule.

The concentration of each element in seawater is determined by

the rate of addition and the rate of removal.

The current accepted definition of salinity is based on

the ratio of the electrical conductivity to that of a standard solution.

If the concentration of a gas in the surface layer of seawater is greater than the saturation solubility

there will be a net transfer of gas from the water to the atmosphere.

Tropical waters are particularly vulnerable to oxygen-consuming organic pollutants because

they have naturally low oxygen levels as the saturation solubility is lower at the warmer temperatures.

Most of the water that Mercury, Venus, and Mars had originally

was lost to space early in these planets' histories because of their low gravity.

Ocean sediments are recycled over millions of years

when the sedimentary rocks are subducted into the mantle, melted, and incorporated into magma.