1 / 54

Properties of Water

Properties of Water. Water Molecule. Like repels – push apart Opposite attracts – come together. Magnet – like charges repel ; unlike (opposite) charges attract Electrically charged particles are polar. Polarity. Oxygen - negative Hydrogen - positive

conlan
Download Presentation

Properties of Water

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Properties of Water

  2. Water Molecule

  3. Like repels – push apartOpposite attracts – come together Magnet – like charges repel; unlike (opposite) charges attract Electrically charged particles are polar

  4. Polarity • Oxygen - negative • Hydrogen - positive • Magnet – like charges repel; unlike (opposite) charges attract • Electrically charged particles are polar • Wateris a“polar molecule”

  5. Water is a Polar Molecule • The polar nature of water molecules causes the molecules to attract each other. Like weak magnets, a positive pole (hydrogen) on each water molelcule attracts thenegative pole (oxygen) • This attraction causes molecules to form temporary bonds. These bonds form and break easily, and help water to stick together.

  6. Water being a Polar Molecule causes it to have many unique properties. Demo

  7. Surface Tension

  8. Surface Tension • A force that causes the tightness across the surface of water • Caused bypolar molecules • Examples • water strider walking on water • raindrops beading on car windshield

  9. Adhesion– is the attractive force between two differentsubstances that are in contact with each other. • Because of their shape, water molecules are attracted to other substances - Ex: Band-Aids • Ex: Drops of water left on your skin after a swim

  10. . Cohesion - the force that holds molecules of a single material together • Because of their shape water molecules are attracted to one another. • Water forms “drops” because of cohesion. • Cohesion is responsible for clouds forming in the atmosphere (drops attract drops)

  11. We see evidence of adhesion and cohesion and surface tension every day. Here’s an example.

  12. Capillary Action • The movement of water within the spaces of a porous material due to the forces of adhesion, cohesion and surface tension

  13. Capillary Action in the “Real World”

  14. Capillary Action

  15. Molecules in Motion • Candy – roll it around • Molecules in motion • Dissolving • Solute • Solvent • Solution Leads us to another Property of Water

  16. Universal Solvent • Solute – the dissolved substance – Candy • Solvent – liquid capable of dissolving - Saliva • Solution – a substance dissolved in water – the substance after the candy has dissolved with your saliva • Water is called theUniversal Solventbecause it can dissolve more substances than any other known substance. Most substances dissolve in WATER

  17. Water Changes States • Evaporation • Condensation

  18. Density – the amount of mass per volume in a given substance D=m/vDifferent of Different Substances Density of water is 1g/cm3 Ice – 0.92g/cm3 Oil – 0.8 g/cm3 Aluminum – 2.7 g/cm3 Iron – 7.87 g/cm3 Glass – 2.6 g/cm3 Oak (wood)– 0.7 g/cm3 Dogwood – 0.75 g/cm3

  19. 1. When water cools, the molecules line up in a grid like crystal structure 2. The molecules take up more space as ice than it did in liquid form Therefore, ice is less dense than liquid water Density of water is 1g/cm3 It has buoyancy - the ability to float Why Ice Floats

  20. Picture of Gridlock Structure that enables ICE to float.

  21. Ice Floating • Important for fish and other organisms that live in water. WHY? • When lakes and ponds freeze in winter, the ice stays at the top. • The fish are able to live in the water below the ice and find food on the bottom of the lake. • If ice acted as most substances do when they freeze, the ice would sink to the bottom of the lake as it formed. Oh no!! What would happen to the “TURTLES”!!

  22. Review: Density of Water • Density of water = 1g/cm3 • Water becomes less dense when it becomes a solid. • Reason: Due to the water molecules grid-like structure; ice is less dense than water • **Water is actually most dense at 40C

  23. If the buoyant force is greater than or equal to the weight of the object, than it will float

  24. Specific Heat - continued • Water requires a lot of heat to increase its temperature • Water has a high specific heat due to the many attractions among water molecules • Effect: • Land has less dramatic temperature changes • Air is warmer inland than on the coast • Water remains warm and keeps the air above it warmer than the air over the cold land

  25. Water and Land - different temperatures because of Specific Heat

  26. Substance Gold Silver Iron Air Wood Olive Oil Water Specific Heat (cal/g C) .03 .06 .11 .24 .44 .47 1.0 Specific HeatAnother Property of WaterThe amount of heat needed to raise the temperature of one gram of a substance by one degree Celsius.

  27. Properties of Water Many are due to it’s Polar StructureOne Negative Oxygen atom + 2 Positive Hydrogen atoms = • Surface Tension • Adhesion – cohesion – capillary action • Universal solvent • Ice floats • Condensation – Evaporation • Specific Heat • Density of water – 1g/cm3 H2O

  28. Standardized Test Practice Question 1 A water molecule is composed of which of the following? A. one hydrogen atom and an oxygen atom B. one hydrogen atom and two oxygen atoms C. three oxygen atoms and one hydrogen atom D. two hydrogen atoms and one oxygen atom NC: 3.01

  29. Standardized Test Practice The answer is D. Water is composed of two hydrogen atoms bonded to one oxygen atom. It is called a “polar molecule” NC: 3.01

  30. Question 2 . Water has a ________ and ________ end making it a polar molecule. Because of its polarity, water can dissolve other substances. Because of the polarity of the water molecule, ice will _______ on water. positive negative float NC: 3.01

  31. Question 3 What property of water causes water to stick to other water molecules? NC: 3.01

  32. Cohesion is the attraction between water molecules. It helps keep water liquid at room temperature and allows water to form into drops. NC: 3.01

  33. Standardized Test Practice Question 4 During which process does water cycle from Earth’s surface to the atmosphere? A. condensation B. evaporation C. infiltration D. precipitation

  34. Standardized Test Practice The answer is B. Water evaporates from Earth’s surface and enters the atmosphere as water vapor.

  35. Standardized Test Practice Question 5 The attraction between water molecules is called ________. A. aquifer B. cohesion C. density D. specific heat NC: 3.01

  36. Standardized Test Practice The answer is B. Cohesionis the attraction between water molecules that allows water to form droplets. NC: 3.01

  37. Properties of Water Polar Molecule Cohesion Adhesion Capillary Action Universal Solvent Why ice floats Density of water Buoyancy Specific Heat Know more than just the definition.Understand how to apply the term!

  38. Time for Quiz

  39. Time for Activity

  40. Penny Predictions • Independent Variable- The part of the experiment that you changed. • Dependent Variable - The part of the experiment that changed as a result of what you changed. • Controlled Variables: What stayed the same?

More Related