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Water Cycle What is a polar molecule Has polar bonds Water has polar covalent bonds Oxygen is more electronegative than H Electrons of covalent bonds spend more time closer to Oxygen than to H ID: 999491 Download Presentation
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Presentation on theme: "Properties of Water What molecule supports all of life"— Presentation transcript
1. Properties of Water
2. What molecule supports all of life?
3. Water Cycle
4. What is a polar molecule?Has polar bonds:Water has polar covalent bondsOxygen is more electronegative than HElectrons of covalent bonds spend more time closer to Oxygen than to HCreates a polar moleculeO region is partially negativeH regions are partially positiveCauses the properties of water
5. POLAR MOLECULEHOHH2O++–
6. HYDROGEN BONDS–Water(H2O)Ammonia(NH3)Hydrogen bond++–+++
7. States of Water
8. How does this change when water is in different states?Slightly positive H of 1 molecule is attracted to slightly negative O of nearby molecule creating a H bond that holds those molecules together
9. Water and PolarityHydrogenbonds
10. What are the Properties of Water?AdhesionCohesionSurface TensionHigh specific heatExpands when frozenUniversal solvent
11. 1. CohesionCohesion – water “sticking” to itself
12. 1. CohesionCohesion contributes to transport of water and dissolved nutrients against gravity in plants
13. 2. AdhesionAdhesion is water “sticking” to something else
14. Cohesion is supported by AdhesionWhat is Adhesion?clinging of one substance to anotherAdhesion of water to cell walls by those same hydrogen bonds
15. Adhesion vs. Cohesion
16. 3. Surface TensionHow is this related to Surface Tension?Surface tension= how difficult it is to stretch or break the surface of a liquid
17. Examples of surface tension
18. Benefits of properties 1-3:Bugs that walk on waterBugs that use air bubble to breathe underwaterLeads to transport of water and its dissolved nutrients against gravity in plantsWater molecules leaving plants by evaporation cause H bonds to tug on water molecules, creating an upward force of water in the plant
19. Water and TemperatureHydrogenbonds
20. 4. High Heat Capacity a.k.a. High Specific Heat Water’s temperature does not change easilyWater can absorb or release a good deal of heat before its overall temperature changes.
21. What is specific heat?the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1 °C
22. Evaporative Cooling
23. Benefits of having a high heat capacity:Keeps temperatures more constant in bodies of water so animals can survive betterKeeps water warm on a cool day and cool on a hot day, and in turn, cools the air around it on a hot day and heats air around it on a cool dayKeeps temperature from fluctuating greatly due to the fact that oceans cover the earthHelps moderate Earth’s climate Contributes to stability of temperature in lakes and ponds Prevents land organisms for overheating
24. What happens to the ice?
25. 5. Expansion Upon FreezingWater is less dense as a solid than as a liquidIce FloatsBegins freezing when its molecules are no longer moving vigorously enough to break their hydrogen bondsBecomes about 10% less dense
26.
27. Hydrogen Bond angles
28. Benefits of water expanding upon freezing:Fish get to survive in cold temperaturesWe get cold drinks
29. 6. Universal Solvent
30. A few terms regarding solutions…Solution-Liquid that is completely homogeneous mixture of two or more substancesSolvent-Dissolving agent of a solutionSolute-Substance that is dissolvedAqueous solution-Solution in which water is the solvent
31. Solution
32. Suspension
33. Colloid(This is why you should shake milk first!)
34. Why is water a versatile solvent?Due to polarity of the ionsIons have mutual affinity through electrical attraction of the opposite chargesCompounds don’t have to be ionic to dissolve waterDissolve when water molecules surround each of the solute molecules, forming hydrogen bonds with them
35. Hydrophilic – any substance that “loves” water and dissolves easily into itHydrophobic – any substance that “hates” or repels water and will not mix with it
36. Benefits of water’s solubility:Allows the movement of solvents through cohesionMakes the solvent hydrophilic, benefitting cellular processes
37. QUIZ TIME!The model illustrates hydrogen bonding found in water. This attraction between water molecules is the result of water’sA ionic bonding.B polar covalent bonding.C positively charged atoms.D negatively charged atoms.
38. Which property of water is displayed here?
39. Which property of water is displayed here?
40. Which property of water is displayed here?
41. Which property of water is displayed here?
42. Which property of water is displayed here?
43. Which property of water is displayed here?