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Water Properties SC.912.L.18.12. Water has unique properties that make it an important substance for life. Cohesion and Adhesion. Hkhkhjhkjhkh Cohesion is an attraction between substances of the same kind.
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Water PropertiesSC.912.L.18.12 Water has unique properties that make it an important substance for life.
Cohesion and Adhesion Hkhkhjhkjhkh Cohesion is an attraction between substances of the same kind. Example: Hydrogen bonds between water molecules cause the cohesion of liquid water. Because of cohesion, water and other liquids form thin films and drops.
Adhesion • Adhesion is an attraction • between different substances. • Water molecules are attracted • to many other similarly polarized • substances • Example: Adhesion powers • capillary action, where H20 • molecules move upward thru • a narrow tube, such as the stem • of a plant.
Stores Heat Energy • Water absorbs heat • more slowly and • retains this energy • longer than many other substances do. Many organisms release excess heat through water evaporation. Example: Humans cool themselves by sweating. The water vapor lost through the evaporation of sweat carries heat away from the body.
Universal Solvent • Water has the ability to • dissolve many substances. • The polarity of water • enables many substances to dissolve in water. Example: Ionic compounds and polar molecules dissolve best in water
Surface Tension • Water molecules • like to cling to one • another. At the • surface, there are fewer water molecules to cling since there is air above (no water molecules). This results in a stronger bond between those molecules that actually do come in contact with one another and a layer of strongly bonded water. Example: Small insects such as the water strider can walk on water because their weight is not enough to penetrate the surface.
Review Questions: Why is water a good solvent for many ionic compounds? Water has the ability to store heat longer than other substances. What benefit does this property of water provide to organisms?