Chemical Properties of Water

The Water Molecule: Di-hydrogen monoxide H2O Water is a polar molecule. It has a charge like a magnet and will attract or repel other molecules.

Cohesion is the term for attraction between different water molecules Cohesion is the term for attraction between different water molecules. Think surface tension. Adhesion is the term for attraction between water molecules and other molecules. Think capillary action on a paper towel.

Adhesion, Cohesion and Surface Tension Adhesion: Water and Other Things Cohesion: Water and Water Surface Tension: due to cohesion. See the demos!

Parts of a Solution Solvent = the liquid that does the dissolving. Solute = the solid that gets dissolved. Precipitate = a salt that separates from a solution after an acid-base neutralization. Water is considered to be the “universal solvent”. It will dissolve almost anything.

The Acidification of the Oceans Everyday, humans are adding carbon dioxide to our atmosphere and oceans. Carbon dioxide added to water makes the water more acidic. High concentrations of acid are harmful to living organisms especially those who have shells made of calcium carbonate and corals. Watch the video to learn more…

Salinity The amount of solids dissolved in water; usually “salts”. The composition of the oceans has remained unchanged for 1.5 billion yrs. Salts are primarily added through runoff and removed by precipitation and evaporation. The amount of solids dissolved in water; usually “salts”. Salt: not just NaCl (table salt), includes other dissolved minerals. Ocean water is 96.5% H2O, the remaining 3.5% are mostly sodium and chlorine.

Measuring Salinity Number of grams of solids in 1 kg of water. Parts per thousand (grams per liter) Written # 0/00

Fresh vs. Salt Water Salinity: parts of salt / parts of water Density: grams / cubic centimeter  Fresh = 1.00 g/cm3  Salt = 1.026 g/cm3

Sea Salt Cycling The composition of the oceans has remained unchanged for 1.5 billion yrs. Salts are primarily added through runoff and removed by precipitation and evaporation. The Principle of Constant Proportions The proportions of the major conservative elements in seawater remain nearly constant, though total salinity may change by location.

Specific Heat Capacity Every substance has a unique ability of absorb and release heat. This is the specific heat capacity. Water has a very high specific heat capacity and will heat and cool very slowly. NASA BALLOON VIDEO

Temp and Salinity The warmer the water the more you can dissolve in it. Freezing or evaporating water removes the impurities and are processes used for desalinization. [Watch the Video] A thermocline shows the point in the ocean where temperature rapidly changes. A halocline shows the point in the ocean where the salinity rapidly changes.