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Explore the fascinating properties of water and its role in chemical reactions and solutions. Discover the polarity of water, its solubility, and the importance of hydrogen bonding. Learn about cohesion, adhesion, temperature moderation, density of ice, and the chemical behavior of acids and bases.
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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
Acidic • 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