Unique Water Properties Energy and Matter Unique Water Properties

Water and Solutions In comparison to a jellyfish, our bodies are both made up of cells composed mostly of water. Chemical reactions occurs in aqueous solutions

Polarity Water molecule Hydrogen shares electrons with oxygen Hydrogen bonds are formed at an angle Negative charge on oxygen and positive charges on Hydrogen create a polar compound

Solubility of Water Polar can dissolve other polar substances Dissolved substances are found in all living things Essential to maintain normal body functions Muscle contractions Nerve impulses

Hydrogen Bonding Hydrogen bonds allow water molecules to “cling” to each other & other substances Provide the unique properties of water Adhesion Cohesion Temperature Moderation Density of ice Polarity

Cohesion Water molecules stick to each other Surface tension

Adhesion Attraction to different substances Glass molecules and water Capillary action

Temperature Moderation Absorb or release large amounts of energy with just a slight change in its own temperature Specific heat Hydrogen bonds Water can absorb large amount of energy from sun during the day and slowly release it at night Oceans stabilize Earth’s temperature Organism’s can keep cells at even temperature despite changes in the environment

Temperature Moderation Evaporative cooling Liquid evaporates taking heat with it Remaining liquid is cool Prevents overheating of land organisms

Density of Ice Solid water is less dense than liquid Shape of water molecule & hydrogen bonding Angle between hydrogen atoms so wide that open spaces are formed as it becomes solid Ice floats Ponds and lakes freeze top down Important for aquatic organisms

Acids and Bases Ionization of water Water molecules move Collisions occur & some strong enough to knock off a Hydrogen atom The loose Hydrogen then joins another water molecule H2O <-> H+ + OH- (Hydroxide ion) H+ + H2O <-> H3O + (Hydronium ion) If hydronium ions are greater solution is acidic

pH scale (0 acidic, 7 neutral, 14 basic) Buffers H3O + (Hydronium ion) Sour taste and highly corrosive Basic or Alkaline OH- (Hydroxide ion) Bitter taste and slippery pH scale (0 acidic, 7 neutral, 14 basic) Buffers Chemical substances used to neutralize small amounts of either an acid or base