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What makes water so special?. Water three A water molecule (H 2 O), is made up of three atoms --- one oxygen and two hydrogen. H H O.

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Presentation on theme: "What makes water so special?. Water three A water molecule (H 2 O), is made up of three atoms --- one oxygen and two hydrogen. H H O."— Presentation transcript:

1 What makes water so special?

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

3 So…what makes water so special?

4 Water is Polar!!!! oxygennegative The oxygen end acts negative hydrogenpositive The hydrogen end acts positive POLAR, like a magnet. Causes the water to be POLAR, like a magnet.

5 Hydrogen Bonds Exist Between Water Molecules Formed between a highly Electronegative atom (like oxygen in another water) of a polar molecule and a hydrogen Formed between a highly Electronegative atom (like oxygen in another water) of a polar molecule and a hydrogen Weak bond, but strong in great numbers (ask about Crocodile Dundee) Weak bond, but strong in great numbers (ask about Crocodile Dundee)

6 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

7 What are the Properties of Water?

8 Properties of Water Cohesion Cohesion

9 Properties of Water Cohesion Cohesion Adhesion Adhesion

10 Properties of Water Cohesion Cohesion Adhesion Adhesion High Specific Heat High Specific Heat

11 Properties of Water Cohesion Cohesion Adhesion Adhesion High Specific Heat High Specific Heat High Heat of Vaporization High Heat of Vaporization

12 Properties of Water Cohesion Cohesion Adhesion Adhesion High Specific Heat High Specific Heat High Heat of Vaporization High Heat of Vaporization Less Dense as a Solid Less Dense as a Solid

13 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)

14 Cohesion … Helps insects walk across water, but how is it helpful to people?

15 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.

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

17 High Specific Heat Amount of heat needed to raise or lower 1g of a substance 1° C. Amount of heat needed to raise or lower 1g of a substance 1° C. Water resists temperature change, both for heating and cooling. Water resists temperature change, both for heating and cooling. – Would you rather walk on sand or in water on a beach on a hot summer day? – Which would be warmer that night? Why?

18 High Heat of Vaporization

19 Water vapor Water vapor forms a kind of global blanket which helps to keep the Earth warm. Heat radiated from the sun Heat radiated from the sun warmed surface of the earth is absorbed and held by the vapor by the vapor.

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

21 Solutions & Suspensions Water is usually part of a mixture. Water is usually part of a mixture. There are two types of mixtures: There are two types of mixtures: – Solutions: substance dissolves in liquid – Suspensions: substance suspends in liquid Come up with examples Come up with examples

22 Solutions Water is the solvent, salt is the solute salt water is the solution

23 Suspensions dont dissolve but separate Substances that dont dissolve but separate into tiny pieces.

24 Acids, Bases and pH One water molecule is made of two ions, (H+) and a Hydroxide Ion (OH-) Hydrogen Ion Hydroxide Ion Acid Base Acid Base H 2 O H + + OH -

25 Acids and Bases A solution with lots of H + ions Acid: A solution with lots of H + ions 0 up to 7 is acid (acidic) pH 0 up to 7 is acid (acidic) A solution with lots of ions Base: A solution with lots of OH - ions above 7 – 14 is b pH above 7 – 14 is basic (alkaline)

26 percent of H + ions Indicates the percent of H + ions 0 – 14 Ranges from 0 – 14 7 is neutral pH of 7 is neutral 10X Each pH unit represents a factor of 10X change in concentration – pH 3 is 10 x 10 x 10 (1000x) stronger than a pH of 6 The pH Scale…acids

27 The pH Scale…bases

28 Buffers Weak acids or bases that react with strong acids or bases to prevent sharp, sudden changes in pH (neutralization). Weak acids or bases that react with strong acids or bases to prevent sharp, sudden changes in pH (neutralization). Produced naturally by the body to maintain homeostasis Produced naturally by the body to maintain homeostasis Weak Acid Weak Base

29 Human biology and pH Your blood maintains a pH of 7.35 – 7.45 (slightly basic) – Balance is maintained by buffers in blood, breathing, and urinating The human vaginal canal has a pH of 3.8 – 4.5… Why?

30 Write down 3 questions you have.

31 Quick Quiz

32 1.Draw a water molecule with labeled atoms and charges. 2.What is the property called that describes water sticking to itself? 3.What makes a solution acidic? 4.What has a higher pH, bleach or lemon juice? 5.Why do we sweat?

33 Quick Quiz 1.Draw a water molecule with labeled atoms and charges.

34 Quick Quiz 1.Draw a water molecule with labeled atoms and charges. 2.What is the property called that describes water sticking to itself?

35 Quick Quiz 1.Draw a water molecule with labeled atoms and charges. 2.What is the property called that describes water sticking to itself? 3.What makes a solution acidic?

36 Quick Quiz 1.Draw a water molecule with labeled atoms and charges. 2.What is the property called that describes water sticking to itself? 3.What makes a solution acidic? 4.What has a higher pH, bleach or lemon juice?

37 Quick Quiz 1.Draw a water molecule with labeled atoms and charges. 2.What is the property called that describes water sticking to itself? 3.What makes a solution acidic? 4.What has a higher pH, bleach or lemon juice? 5.Why do we sweat?


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