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Notes Outline: Students will copy and fill in.

Notes Outline: Students will copy and fill in. Objectives. Understand that water is polar, which results in hydrogen bonding. Identify the major properties of water that result from the hydrogen bonding.

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Notes Outline: Students will copy and fill in.

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  1. Notes Outline: Students will copy and fill in.

  2. Objectives • Understand that water is polar, which results in hydrogen bonding. • Identify the major properties of water that result from the hydrogen bonding. • Distinguish among the factors that make water a unique substance and understand their biological relevance. • Understand how the presence of substances dissolved in water will affect the properties of water. • pH • Acids & Bases

  3. Vocabulary • Cohesion • Adhesion • Solution • Acid • Base • pH • Buffer

  4. Employ the Knowledge • Watch the video and write down at least 5 things mentioned about how amazing water is. http://youtu.be/HVT3Y3_gHGg

  5. Water • One of the most important substances on Earth. • It looks plain. It’s odorless, tasteless, and everywhere. • But, without question, water is one of the biggest reasons life exists as it does.

  6. Water Chemistry • Water is constructed from a covalent bond between two hydrogen atoms and an oxygen molecule. • Because of where oxygen’s absent valence electrons are, this bond forms a bent molecule, making it polar. • Being polar is incredibly important to its properties… how it behaves chemically.

  7. Water is Polar: Electrons are not shared equally. - Partially - - - - - - - - - - Partially +

  8. Properties of Water • Being polar gives water a partial positive charge on one end and a negative charge on the other. • Specifically; • Oxygen = Negative End • Hydrogen = Positive End • The attraction between the positive (H) of one water molecule and the negative (O) of another causes a bond to form, called a HYDROGEN BOND. • These bonds make most of what water does possible.

  9. Properties • Water’s characteristic of being a polar molecule, allowing it to form hydrogen bonds is responsible for many of its properties. Some of these properties are: • Cohesion & Surface Tension • High Heat Capacity/Specific Heat • Resists Evaporation: (High Heat of Vaporization) • Floats in Solid State • Adhesion: • Capillary Action • Universal Solvent

  10. Property #1: Cohesion • The attraction of particles of the same substance, such as water bonding to water, is called cohesion. • The resulting attraction forms hydrogen bonds. • Cohesion keeps water from evaporating easily; thus, water is a liquid at ordinary temperatures. • It allows for water to maintain a high surface tension. Biological Relevance (BR): Water can form hydrogen bonds with itself, giving it many more properties. • What it surface tension? • The resistance water has against something pushing down on it. If the surface tension is greater than the force pushing down, the substance will sit on top of the water… not float, literally sit on top water.

  11. Property #2: High Heat Capacity • More than most substances…Water can absorb a large amount of heat without changing temperature. • BR: This property can help organisms maintain a constant internal temperature when the outside changes dramatically. • This is mostly due to the hydrogen bonds. • When energy in the form of heat enters water it is efficiently distributed the molecules of water by breaking and re-forming new hydrogen bonds • It takes a lot of energy to heat water just 1 degree.

  12. Property #3 Resistance to Evaporation • Evaporation happens as the motion of water molecules causes some to break hydrogen bonds and leave to the atmosphere. • Water is one of the most resistance fluids to boiling and evaporation. • The energy absorbed is dispersed in the trillions of hydrogen bonds in water molecules, rarely allowing water molecules to evaporate. • BR: Water stays more often as a fluid instead of a gas, which allows chemical reactions of life to happen. Energy

  13. Property #4: Water Floats when Frozen • Biological relevance (BR): INSULATION: This enables life to survive in warmer liquid water below the ice, insulated from the elements above and prevents most deep bodies of water from freezing solid. • This is unique to water. Everything else becomes more dense and sinks as it freezes. • When water freezes, the crystal structure formed due to hydrogen bonding makes ice less dense than liquid water. • Because it is less dense than liquid water, when water freezes it floats to the top.

  14. Property #5: Adhesion • The attraction between particles of different substances is called adhesion. • BR: Water molecules also stick and react to other polar molecules. • This is important property for plants especially. • This property, along w/ cohesion, allows water to travel upwards through stems and trunk.

  15. #6. Capillary Action • Adhesion + Cohesion gives water the property of climbing through the tight veins of plants that are also made of polar compounds. • BR: Water can climb against gravity so plants can get water to the top limbs/branches.

  16. #7. Universal Solvent • Because of its polarity, water is capable of dissolving many polar substances with charge (molecules and ions…even itself) • Therefore, water is a very efficient solvent. BR: This property helps water become a medium for chemical reactions in the body. • What’s dissolved in soda? • Carbon dioxide • HFCS • Salts • Caffeine • Ect.

  17. The properties of water revisited Because water is a polar molecule, that forms many hydrogen bonds with itself and other polar molecules, water: • Floats in Solid State • Absorbs Energy: High Heat Capacity/Specific Heat • Resists Evaporation/High Heat of Vaporization • Is Cohesive: Surface Tension • Is Adhesive: • Performs Capillary Action • Is a Universal Solvent It is your responsibility to know these properties, be able to define them, and explain why these are biologically relevant.

  18. Employ the Knowledge • Review the video again. See if it makes more sense. • While watching, reflect on one thing you’ve learned new about water on your warm up log. http://youtu.be/HVT3Y3_gHGg

  19. Water As a Solvent & Solutions • Water is the primary, most important medium for solutions that allowed life to develop on Earth. • A solutionis a mixture in which ions or molecules of one or more substances are evenly distributed in another substance (a fluid). • A solvent is a fluid that dissolves something. • A solute is the substance that gets dissolved. • Facts: • Water dissolves many ionic and polar substances • Water does not dissolve non-polar substances, like oils. • Many substances are transported throughout living things as solutions of water. • Dissolved substances can move more easily within, in and out of, and between cells.

  20. Solutions Acids and Bases • Water is such a good solvent it can dissolve itself. • Spontaneously and reversibly, when this happens water breaks apart to form hydronium and hydroxide ions. • In pure water, hydronium and hydroxide ions are present in equal numbers. • Making it neutral. • Sometimes, when some substances are dissolved in water extra hydronium or hydroxides are formed as well. • Acids and bases are solutions that result from this imbalance of hydronium (or hydrogen ions) or hydroxides and water.

  21. Solutions

  22. Solutions, Acids and Bases • Acids are fluid compounds that form extra hydronium ions dissolved in water. • Bases are fluid compounds that form extra hydroxide ions dissolved in water. • You create acids or bases by dissolving substances, such as chlorine, in water. • When acids and bases are mixed, the extra hydronium and hydroxide ions neutralize each other to form water.

  23. Solutions pH and Buffers • pH is a measure of how acidic or basic a solution is. • Pure water has a pH of 7.0, which is right in the middle of the pH scale • It’s neither acidic or basic • pH is decided by how many hydronium ions are present in the solution. • Each one-point increase in pH represents a 10-fold decrease in hydronium ion concentration. • Eventually, you’ll get to the point where the concentration of hydronium ions is taken over by hydroxide ions. • This occurs at pH 7, which is neutral.

  24. How Do You Measure the pH of Substances? • Pure water has a pH of 7. • Acidic solutions have a pH below 7 (lots of hydronium). • Basic solutions have a pH above 7 (lots of hydroxide).

  25. Solutions • All the properties of water studied so far are based upon water in its pure form…only H2O. • But as a solvent, we can add things to water, which can inspire changes. • It conducts cohesion and adhesion = Chemical reactions can take place and things can dissolve. • pH can change = Acids and bases can form. • Physical properties can change = melting & boiling points can change. • For example, a car’s radiator contains a solution of water and ethylene glycol. This solution acts as antifreeze because the freezing point is −30 °C. It also helps prevent boiling in hot weather because the boiling point is 109 °C. • Another example, the boiling point of pure water is 100 °C and the freezing point is 0 °C. If you dissolve 12 g of sodium chloride in 100 mL of water, the boiling point of the solution increases from 100 °C to 102 °C. The freezing point decreases from 0 °C to −8 °C.

  26. Solutions, continued pH and Buffers • The pH of human blood is close to 7.35, but things we absorb into our blood streams can change this. • The pH of solutions in living things must be stable. • For a stable pH to be maintained, the solutions in living things contain buffers. • Example: Drinking too much soda and not enough water can lower the pH of our blood making our kidneys work too hard • A buffer is a substance that reacts to prevent pH changes in a solution. • Luckily, our blood is buffered in a bicarbonate solution so that when we eat certain foods they don’t affect our pH too much when they are broken down.

  27. Conclusion • Water derives all of its major properties from the fact that it is a polar molecule, capable of forming hydrogen bonds. • You must know: • The structure of water, making it a polar molecule. • What hydrogen bonds are and how they form. • The 7 properties of life & how they are biologically relevant. • That, being a solvent, things dissolved in water changes its chemical properties • pH and other properties.

  28. Think-Pair-Share… take a few minutes and read each situation. Decide which property or characteristic is responsible for the process. ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER

  29. Practice Reviewing Water Properties:Book of Water’s Properties • In a 12-page book, explain the polar characteristic of water, the 7 properties that result from it, and their biological relevance. • Get THREE pieces of paper, fold in half, staple along the seam & Create your book like this: • Cover: Title and Name, with an illustration of what the book’s about. • Page 1: Table of contents • Page 2: Illustrate and explain molecular construction of water, the characteristic of water being a polar molecule, and an explanation of hydrogen bonding. • Pages 3-9: Identify, explain, and illustrate each of the 7 properties discussed today plus the biological relevance in the order given. • Page 10: Summarize the 7 properties of water & Summarize how water is beneficial to life by including 3 biological relevant facts in one paragraph. • Rubric: 60 pts total. 3pts per page = explanation of the characteristics and properties of water. + 2pts per page for illustrations and neatness. Be creative and ask questions if you need to. Due __________. Use time in class appropriately. All written parts must be in your own handwriting. You may include computer illustrations but it’s not required. Just label appropriately.

  30. Practice Reviewing Water Properties:Book of Water’s Properties • In a 12-page book, explain the polar characteristic of water, the 7 properties that result from it, and their biological relevance. • Get THREE pieces of paper, fold in half, staple along the seam & Create your book like this: • Cover: Title and Name, with an illustration of what the book’s about. • Page 1: Table of contents • Page 2: Illustrate and explain molecular construction of water, the characteristic of water being a polar molecule, and an explanation of hydrogen bonding. • Pages 3-9: Identify, explain, and illustrate each of the 7 properties discussed today plus the biological relevance in the order given. • Page 10: Summarize the 7 properties of water & Summarize how water is beneficial to life by including 3 biological relevant facts in one paragraph. • Rubric: 60 pts total. 3pts per page = explanation of the characteristics and properties of water. + 2pts per page for illustrations and neatness. Be creative and ask questions if you need to. Due __________. Use time in class appropriately. All written parts must be in your own handwriting. You may include computer illustrations but it’s not required. Just label appropriately.

  31. Practice Reviewing Water Properties:Book of Water’s Properties • In a 12-page book, explain the polar characteristic of water, the 7 properties that result from it, and their biological relevance. • Get THREE pieces of paper, fold in half, staple along the seam & Create your book like this: • Cover: Title and Name, with an illustration of what the book’s about. • Page 1: Table of contents • Page 2: Illustrate and explain molecular construction of water, the characteristic of water being a polar molecule, and an explanation of hydrogen bonding. • Pages 3-9: Identify, explain, and illustrate each of the 7 properties discussed today plus the biological relevance in the order given. • Page 10: Summarize the 7 properties of water & Summarize how water is beneficial to life by including 3 biological relevant facts in one paragraph. • Rubric: 60 pts total. 3pts per page = explanation of the characteristics and properties of water. + 2pts per page for illustrations and neatness. Be creative and ask questions if you need to. Due __________. Use time in class appropriately. All written parts must be in your own handwriting. You may include computer illustrations but it’s not required. Just label appropriately.

  32. Practice Reviewing Water Properties:Book of Water’s Properties • In a 12-page book, explain the polar characteristic of water, the 7 properties that result from it, and their biological relevance. • Get THREE pieces of paper, fold in half, staple along the seam & Create your book like this: • Cover: Title and Name, with an illustration of what the book’s about. • Page 1: Table of contents • Page 2: Illustrate and explain molecular construction of water, the characteristic of water being a polar molecule, and an explanation of hydrogen bonding. • Pages 3-9: Identify, explain, and illustrate each of the 7 properties discussed today plus the biological relevance in the order given. • Page 10: Summarize the 7 properties of water & Summarize how water is beneficial to life by including 3 biological relevant facts in one paragraph. • Rubric: 60 pts total. 3pts per page = explanation of the characteristics and properties of water. + 2pts per page for illustrations and neatness. Be creative and ask questions if you need to. Due __________. Use time in class appropriately. All written parts must be in your own handwriting. You may include computer illustrations but it’s not required. Just label appropriately.

  33. For HW: Process these properties and apply them to the list of life processes below. ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER ANSWER

  34. Summary • The hydrogen bonding between water molecules explains many of the unique properties that make water an important substance for life. • Acids and bases change the concentration of hydronium ions in aqueous solutions. The pH of solutions in living things must be stable. • Reflection: • Using one property, describe how water makes life possible.

  35. Group Analysis: “Analyze Water Properties” • Get into groups. • Together, work through the questions. • This is due next class (20pts). • Answer key. Is posted online. Check your answers, but please, for your own good, don’t copy.

  36. Pre-Demonstration: Properties of Water • Pre lab questions: • What exactly do expect to happen? Write a hypothesis for this. Be specific and thorough. • We’re going to take some notes today, first we’ll watch a video.

  37. Demonstration: Properties of Water • If you have washable markers (like Crayola or highlighters) get them out. • One sheet of paper per two persons (you and the person sitting next to you). • Follow directions quickly and carefully. • This is a graded “Lab/Exercise” (50 pts) that is due tomorrow. • It is homework and must be turned in 1st thing tomorrow if you do not finish.

  38. Pre-Demonstration: Properties of Water Place this end in the water • Acquire a cup, a large piece of paper towel, and cut a piece of paper towel roughly 3 inches long by 2-3 inches wide. • Fill the cup up most of the way with water and carefully walk it back to your seat. • Carefully color lines across the strip of paper towel about 2 inches from one end. • One mark w/ pencil, one with pen, one with a marker. • If you press too hard you’ll cut your paper in half. • Without submerging your lines…place one end of the paper towel about an inch into the water and let the other end hang off the outer edge of the cup. • Let it sit, undisturbed, for 20 minutes. Two Inches

  39. Post-Demo Analysis (50 pts.) Direction of flow • What do expect to happen? • Write a hypothesis for this. • Write what you observe & draw a picture of it. • What did the water really do? • What properties of water makes this possible? • Research your books and describe what organism uses these same principles and how.

  40. Post-Demo Analysis: Properties of Water 3. Write what you observe & draw a picture of it. What did the water really do? 4. What properties of water makes this possible? 5. Research your books and describe what organism uses these same principles and how. Clean up all materials. Throw paper towels away. Dump water out and stack cups onto pile. Clean up should take less than 3 minutes.

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  42. Water Facts • Water covers 70.9% of the Earth’s surface. • Only 3% of Earth’s water is fresh water. 97% of the water on Earth is salt water... [undrinkable] • 68.7% of the fresh water on Earth is trapped in glaciers, 3% is found in lakes, streams, ponds, and swamps. • 30% of fresh water is in the ground. • Water can dissolve more substances than any other liquid, including sulfuric acid. • A ten meter rise in sea levels due to melting glaciers would flood 25% of the population of the United States. • There is more fresh water in the atmosphere than in all of the rivers on the planet combined. • If all of the water vapor in the Earth’s atmosphere fell at once, distributed evenly, it would only cover the earth with about an inch of water. • Water boils quicker in Denver, Colorado than in New York City. • Approximately 400 billion gallons of water are used in the United States per day. • In one year, the average American residence uses over 100,000 gallons (indoors and outside). • Water is the only substance found on earth naturally in three forms: solid, liquid and gas. • Water makes up between 55-78% of a human’s body weight. • Taking a bath requires up to 70 gallons of water. A five-minute shower uses only 10 to 25 gallons. http://water.epa.gov/learn/kids/drinkingwater/water_trivia_facts.cfm

  43. Water Facts

  44. Did you know.Water Facts • Biological Facts • We are roughly 75% water!

  45. True of False? • 1: Myth – Bottled Water has more minerals • 2: Myth – Vitamin Water is better for you • 3: Fact – The Average American uses around 80 gallons of water a day • 4: Myth – Being thirsty is all down to dehydration • 5: Myth – Drinking water at night will speed your metabolism • 6: Myth – Staying in the pool means that you won’t dehydrate. • 7: Fact – We don’t use much of the Earth’s water. • 8: Fact – You need on average 2.5 liters of water per day. • 9: Myth – All bottled water comes from pure sources. http://eatdrinkbetter.com/2012/08/30/8-water-myths-and-facts/

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