Properties of Seawater

Atoms

Building blocks of matter

Molecule

Substance comprised of bonded atoms

Nucleus

Center of an atom containing protons (+) and neutrons

Electrons

Particles orbiting the nucleus that carry a negative charge

Electron shell

Discrete levels of electron orbits

Isotope

Atoms of the same element with a different number of neutron

Heat

Property that results from the physical vibrations of atoms and molecules

Kinetic energy

Energy of motion

Evaporation

Molecules that contain so much kinetic energy that they escape from the liquid surface and become a gas

Vaporized

When molecules are converted into a gas

Gas

When high energy molecules move independently of one another between collisions

Density

The amount of mass contained in a unit volume

Heat capacity

The quantity of heat required to raise the temperature of 1g of a substance by 1C

Solvent power

The capability of liquid water to dissolve material

Covalent bond

The sharing of electrons between two atoms to create a molecule

Dipole structure

An electrical imbalance in a molecule creating a positive and negative end

Hydrogen bonding

When the negative end of a molecule is attracted to and become electrically bonded to the positive end of a nearby molecule

Cation

Positively charged atom

Anion

Negatively charged atom

Ionic bonds

Bond created by the attraction between a cation and an anion

Saturated

When there is physically no more room in a solution for more ions to dissolve

Hydration

When ions in a solution are surrounded by water molecules

Hexagon

Six sided structure in which the H2O molecules in ice are ordered into

Polymer

Molecules that resemble the open crystalline structure of ice that persist until water reaches 4C

Solvent

The dissolving agent

Solute

The dissolved substances

Two most abundant ions in seawater

Cl- and Na+

Six most abundant ions in seawater

Cl-, Na+, SO4-2, Mg+2, Ca+2, and K+

Conservative property of seawater

Seawater’s major constituents vary little over time

Inert

Unreactive gas

Principle of constant proportion

The relative proportions of the major constituents of seawater are constant

Evaporate

Precipitate produced in an supersaturated environment

Steady state equilibrium

Balance between inputs and outputs

Adsorption

The sticking of ions to a surface

Residence time

Average time that ions remain in a solution

Insolation

The solar energy striking the earth’s surface

Isotherm

Contour lines connecting points of equal water temperature

Thermocline

Sharp vertical temperature gradient

Halocline

Sharp vertical salinity gradient

Stratification

Separation of water in distinct layers based on differences in density

Pycnocline

Sharp vertical density gradient

Saturation value

The amount of gas at equilibrium that can be dissolved by a volume of water at a specific salinity

Solubility

The property of being dissolved or going into a solution

Undersaturation

The state of being below the saturation value

Supersaturation

The state of being over the saturation value

Anoxic

Without oxygen

Advection

The horizontal flow of a fluid

Convection

The vertical flow of a fluid

Buffered system

The mixture of compounds and the nature of the reactions are such that the pH is hardly affected by despite an input or output of H+

Photic zone

Sunlit upper layer

Aphotic zone

No light

Unique properties of seawater

Max density at 4C, exists in three states at all times, high dissolvability, very transparent, surface tension, low compressability, high heat capacity

Effects of salinity on the properties of seawater

Lower freezing temperature, increased density, lower vapor pressure