Water Notes:

Water:

Composed of two hydrogen atoms and one oxygen atoms

H2OPolar Molecule

Polarity:

Unevenly distributed charges due to unequal forces placed on bonding electrons

Oxygen ends slightly negativeHydrogen end slightly positive

Results of Polarity:

Allows water to form Hydrogen Bonds

Result of Polarity:

Hydrophilic: All polar molecules attracted to water

Result of Polarity:

Hydrophobic: Repels non-polar substances such as water

Stabilizes Temperature:

Hydrogen bonds between molecules absorb heat energy, thus molecules do not move faster, therefore temperature does not rise as quickly

Need more heat energy to change temperature

Cohesiveness:

Hydrogen bonding locks molecules together

Surface Tension: Cohesion at the water’s surface

Cohesiveness:

Adhesion: when water attaches to non-water molecules

ADHESION

COHESION

Cohesiveness:

Capillary Action: Movement of water up

Universal Solvent:

Ions and polar molecules readily dissolve in water

Substances such as salt are pulled apart by attraction of opposite charges due to polar structures

Density:

Water has a density of 1g/mLOne of the few substances that is less

dense as a solid than liquidDue to hydrogen bonding and resultant

pockets

Seawater:

Seawater is slightly different due to the materials dissolved in it

These materials come from the chemical weathering of rocks on land and carried to the sea by rivers while the others are released into the ocean by hydrothermal vents

Solutes:

Solutes – dissolved materials98% of the solutes in sea water are

comprised of 6 ions (charged atoms)Of which 85% of the solids are comprised

of Sodium and Chloride, hence the salt taste

Salinity:

Total amount of salt dissolved in seawaterExpressed as number of grams of salt left

behind when 1,000g of seawater is evaporated

Effects on Organisms:

Slight changes in salinity can harm organisms

Some have developed adaptations to live in estuarine environments

Temperature:

The open ocean will range from -2° C and +30° C

Salt water freezes at a colder temperature than pure water

Density:

If it has more salt it is more denseIf it is colder it is more dense

Dissolved Gases:

The three most important gases for life are dissolved in the ocean:◦Oxygen◦Carbon Dioxide◦Nitrogen

Pressure:

The deeper you go in the ocean, the more pressure

This is due to all the weight of the water and air above you