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The Extraordinary Properties of Water Warm up When atoms loose or gain electrons and become charged, What are they called? What are positively charged.

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Presentation on theme: "The Extraordinary Properties of Water Warm up When atoms loose or gain electrons and become charged, What are they called? What are positively charged."— Presentation transcript:

1 The Extraordinary Properties of Water Warm up When atoms loose or gain electrons and become charged, What are they called? What are positively charged ones called? What are the negatively charged ones called?

2 Water threeA water molecule (H 2 O), is made up of three atoms --- one oxygen and two hydrogen. H H O

3 Water is Polar oxygen atom attracts more electronsIn each water molecule, the oxygen atom attracts more than its "fair share" of electrons oxygennegativeThe oxygen end acts negative hydrogenpositiveThe hydrogen end acts positive POLARCauses the water to be POLAR neutral Zero Net ChargeHowever, Water is neutral (equal number of e- and p+) --- Zero Net Charge

4 Hydrogen Bonds Exist Between Water Molecules Formed between a highly Electronegative atom of a polar molecule and a HydrogenFormed between a highly Electronegative atom of a polar molecule and a Hydrogen One hydrogen bond is weak, but many hydrogen bonds are strongOne hydrogen bond is weak, but many hydrogen bonds are strong

5 Interaction Between Water Molecules Negative Oxygen end of one water molecule is attracted to the Positive Hydrogen end of another water molecule to form a HYDROGEN BOND

6 What are the Properties of Water?

7 Properties of Water At sea level, pure water boils at 100 °C and freezes at 0 °C.At sea level, pure water boils at 100 °C and freezes at 0 °C. The boiling temperature of water decreases at higher elevations (lower atmospheric pressure).The boiling temperature of water decreases at higher elevations (lower atmospheric pressure). For this reason, an egg will take longer to boil at higher altitudesFor this reason, an egg will take longer to boil at higher altitudes

8 Cohesion Attraction between particles of the same substance (why water is attracted to itself)Attraction between particles of the same substance ( why water is attracted to itself) Results in Surface tension (a measure of the strength of waters surface) Results in Surface tension (a measure of the strength of waters surface) Produces a surface film on water that allows insects to walk on the surface of waterProduces a surface film on water that allows insects to walk on the surface of water

9 Cohesion … Helps insects walk across water

10 Introduction: Surface tension refers to water s ability to stick to itself. Surface tension van be measured and observed by dropping water (drop by drop) onto a penny. The number of water drops that can fit on a penny will surprise you. 1.Use the dropper and count how many drops of plain tap water you can fit on a penny. QUESTION: How does soap affect waters surface tension? 2.Rewrite the question and then write a hypothesis that answers the question at the top of page 19 in your BIN.

11 2.Test your hypothesis by comparing the number of drops of plain tap water to the number of drops of soapy water. 3.Do 5 trials of each and determine their averages 4.Create a data table for your results below your hypothesis on page 19 of your BIN 5. Analyze the data and draw conclusions. Write a paragraph below your data table (using complete sentences) that explains how soap affects the surface tension of water, using your data to help you answer the question. Suggest a reason for your observation (why did it happen). Support or reject your hypothesis. Trial 1Trial 2trial3Trial 4Trial 5average Tap water Soapy water

12 Adhesion Attraction between two different substances. Attraction between two different substances. Water will make hydrogen bonds with other surfaces such as glass, soil, plant tissues, and cotton. Water will make hydrogen bonds with other surfaces such as glass, soil, plant tissues, and cotton. Capillary action-water molecules will tow each other along when in a thin glass tube.Capillary action-water molecules will tow each other along when in a thin glass tube. Example: transpiration process which plants and trees remove water from the soil, and paper towels soak up water.Example: transpiration process which plants and trees remove water from the soil, and paper towels soak up water.

13 Adhesion Causes Capillary Action Which gives water the ability to climb structures

14 Adhesion Also Causes Water to … Form spheres & hold onto plant leaves Attach to a silken spider web

15 Water is Less Dense as a Solid Ice is less dense Ice is less dense as a solid than as a liquid (ice floats) hydrogen bonds constantly being broken and reformed. Liquid water has hydrogen bonds that are constantly being broken and reformed. Frozen water crystal-like lattice Frozen water forms a crystal-like lattice whereby molecules are set at fixed distances.

16 Water is Less Dense as a Solid Which is ice and which is water?Which is ice and which is water?

17 Water is Less Dense as a Solid WaterIce

18 Homeostasis Ability to maintain a steady state despite changing conditionsAbility to maintain a steady state despite changing conditions Water is important to this process because:Water is important to this process because: a. Makes a good insulator b. Resists temperature change c. Universal solvent d. Coolant e. Ice protects against temperature extremes (insulates frozen lakes)

19 Solution Ionic compounds disperse as ions in waterIonic compounds disperse as ions in water Evenly distributedEvenly distributed SOLUTESOLUTE –Substance that is being dissolved SOLVENTSOLVENT –Substance into which the solute dissolves

20 Solution


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