Unit 2: Ecology 2.5 Properties of Water
Should we control a chemical that: Causes excessive sweating and vomiting. Is a major component in acid rain. Can cause severe burns in its gaseous state. Accidental inhalation can kill you. Contributes to erosion. Decreases the effectiveness of car brakes. Has been found in tumors of terminal cancer patients.
What is the chemical? Dihydrogen monoxide Otherwise known as H2O
Question? What molecule or compound is the most common In living Cells? Water - most cells are 70 - 95% water
The Water Planet
Properties Of Water Cohesive Adhesive High surface tension Specific Heat- Can hold lots of heat Expands when freezes Versatile solvent
Liquid Water Is Cohesive Cohesion: an attraction between molecules of the same substance Water sticks to water due to the polarity of water resulting in hydrogen boding.
Liquid Water is Adhesive Adhesion: an attraction between molecules of different substances. Water sticks to other polar molecules due its hydrogen bonding
Water transport in trees uses Cohesion and Adhesion
Water Transport in Plants Capillary Action: occurs when water sticks to the sides of a tube and creeps up, pulling other water molecules with them. Imbibition: occurs when porous substances soak up water through capillary action.
Water Has A High Surface Tension The surface of water is difficult to stretch or break. Why? Hydrogen bonding!
Water Stabilizes Temperature Water can absorb and store a huge amount of heat from the sun. Result - climate moderation Result - organisms are able to survive temperature changes.
Water Expands When It Freezes The distance between water molecules increases from the liquid to the solid form. Why? Hydrogen bonding Result: aquatic life can live under the ice
Solids and Liquids Water Benzene Sinks Floats
Water Is A Versatile Solvent Water will form a solution with many materials. Why? Hydrogen bonding!
Solutions SOLUTION: the mix of 2 or more different substance with one substance being liquid SOLVENT: the substance in a solution present in greater amounts (liquid that does the dissolving). SOLUTE: the substance in a solution present in lesser amounts (the substance that is being dissolved).
Hydrophilic Materials Materials that dissolve in water. Hydro - water philic - to like or love Have ionic or polar regions (polar covalent bonds) on their molecules for H+ bonds.
Hydrophobic Materials that repel water. Hydro - water phobic - to fear Have non-polar covalent bonds. Ex - lipids.
Without Water Life Would Not Be Possible!!