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Cat’s Cradle

Cat’s Cradle. IMPORTANCE OF WATER. 1,360,000,000 cubic kilometers of water in the hydrosphere 70% of Earth’s surface Comprises 60-90% of all living organisms Key reactant in both synthetic and catabolic (i.e. breakdown) reactions. WHY WATER?.

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Cat’s Cradle

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  1. Cat’s Cradle

  2. IMPORTANCE OF WATER • 1,360,000,000 cubic kilometers of water in the hydrosphere • 70% of Earth’s surface • Comprises 60-90% of all living organisms • Key reactant in both synthetic and catabolic (i.e. breakdown) reactions

  3. WHY WATER?

  4. The unique physical and chemical properties of water derive from its molecular structure

  5. POLAR COVALENT BOND • Oxygen shares e- unevenly with hydrogen due to its higher electronegativity • As a result, the oxygen end of the molecule appears negatively charged while the hydrogen end appears positive

  6. WHY IS THE POLAR COVALENT BOND SO IMPORTANT?

  7. WATER EXHIBITS BOTH ADHESIVE & COHESIVE PROPERTIES DUE TO POLAR COVALENT BONDING

  8. ADHESION • Water molecules stick to other charged particles • Because water is adhesive it also has the properties of • Universal solvent • Capillary action

  9. UNIVERSAL SOLVENT • “Like dissolves like” • Water dissolves polar solutes. • Water cannot easily dissolve non-polar solutes (i.e. fats, oils)

  10. Why is the ability of water to serve as a nearly universal solvent biologically important?

  11. CAPILLARY ACTION • Water adheres to sides of tubes and other charged surfaces, rising against force of gravity

  12. Why is capillary action a biologically significant property?

  13. COHESION • Water molecules stick to themselves • Because water is cohesive it exhibits the properties of • High Heat of Vaporization • High Surface Tension

  14. HEAT OF VAPORIZATION • Because water molecules cohere, more energy is required to break them apart (i.e. evaporation) • Non-polar substances have less cohesion and hence lower heats of vaporization

  15. VAPORIZATION OF WATER ON A MOLECULAR LEVEL

  16. Why is heat of vaporization biologically significant?

  17. STABILITY OF AQUATIC ECOSYSTEMS

  18. Prevent Changes In Solubility of Gases In Blood Plasma

  19. Apocrine & Eccrine Glands

  20. Surface Tension • As water interfaces with air at the surface, water molecules cohere, creating a less penetrable surface • Surfactants are substances that break surface tension

  21. Why is surface tension a biologically significant property?

  22. RDS – Respiratory Distress Syndrome

  23. Properties of Water Review of Concepts

  24. What type of bonding is exhibited between oxygen and hydrogen in water molecules? A Van der Waal B Polar Covalent C Ionic D Intermolecular

  25. Which property best explains why the bond is polar? A Mass B Density C Shape D Electronegativity

  26. True or False? The tendency of water molecules to stick together is an adhesive property A True B False

  27. Which property of water explains why aquatic ecosystems tend to be more stable in terms of temperature than terrestrial ecosystems? A Heat of Vaporization B Conductivity C Surface Tension D Capillary Action

  28. True or False? Capillary action is a property of water that is attributed to the adhesive nature of water. A True B False

  29. The ability of some insects to live on the surface of pond (due to the naturally high surface tension of water) can be negatively impacted by which substances? Type your answer!

  30. Due to its polar nature, water has the unique ability to break apart other polar substances. This property of water is called... A Heat of Vaporization B Capillary Action C Ability to exist in three states D Universal Solvency

  31. Carbon Dioxide, like water, contains covalent bonds, yet CO2 does not exhibit any of the properties of water. This is because while the bonds of CO2 are covalent they are not _______.

  32. Because these properties of water do not depend upon the amount of matter (unlike mass or pH), these properties are.... A Extensive B Intensive

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