Chapter 3: Water & Life

1.I can explain the significance of polar covalent and hydrogen bonds within and between water molecules. a.I can determine how many water molecules can bond with each other. b. I can describe the four emergent properties of water and explain how each property effects life 1.Adhesion and cohesion 2.Water moderates temperature  High specific heat  Evaporative cooling  High heat of vaporization 3.Water is a versatile solvent 4.Water is less dense when it freezes. Learning targets

Review: Polar Covalent, Non-Polar Covalent & Hydrogen Bonds

 Hydrophilic  Water loving  Ex: salts, sugars, most solubles  Hydrophobic  Water fearing  Ex: fats, oils, waxes Terms to know: Hydrophilic & Hydrophobic

1.I can explain the significance of polar covalent and hydrogen bonds within and between water molecules. a.I can determine how many water molecules can bond with each other. b.I can describe the four emergent properties of water and explain how each property effects life 1.Adhesion and cohesion 2.Water moderates temperature  High specific heat  Evaporative cooling  High heat of vaporization 3.Water is a versatile solvent 4.Water is less dense when it freezes. Learning targets

 How many water molecules can bond with each other? Practice…

What is the charge on this protein? How do you know?

1.I can explain the significance of polar covalent and hydrogen bonds within and between water molecules. a.I can determine how many water molecules can bond with each other. b. I can describe the four emergent properties of water and explain how each property effects life 1.Adhesion and cohesion 2.Water moderates temperature  High specific heat  Evaporative cooling  High heat of vaporization 3.Water is a versatile solvent 4.Water is less dense when it freezes. Learning targets

 Cohesion  Hydrogen bonds make water “stick” to itself  Adhesion  Hydrogen bonds make water “stick” to other polar or charged surfaces 1. Adhesion & Cohesion

 Water transport in plants…. Transpiration  Surface tension Affect on Life

 High specific heat  It takes a lot of energy to change temp  Evaporative cooling  When water molecules evaporate, the remaining surface liquid cools  High heat of vaporization  It takes a lot of energy to convert to gaseous state 2. Water Moderates Temperature

 Climate control near large bodies of water  Sweat dissipates body heat, transpiration keeps plants cool Affect on Life

 Polar molecules mean water is attracted to charged and polar substances that can form H-bonds  Hydrophilic = water loving substances  Hydrophobic = water hating substances 3. Water is a versatile solvent

 Chemical reactions involve or occur in water  Biological fluids  Cell membranes and homeostasis Affect on Life

 Water expands as it freezes  H-bonds lock in place 4. Water is less dense as it freezes

 Ice floats Affect on Life

 Adhesion, cohesion together allow water to “climb” in narrow spaces 5. Capillary Action

 Water moves into and through small spaces  Roots  Leaves of plants (through xylem)  Tears through tear ducts  Absorption into paper towels Affect on Life

 Crash Course: Water- Liquid Awesome Crash Course: Water- Liquid Awesome

2.I can describe how acids and bases affect living organisms. a.I can determine the relationship between H+ and OH- in acidic, basic, and neutral solutions. b.I can relate the relative amounts of H+ and OH- to the pH scale. c.I can explain the logarithmic connection the pH scale. d.I can explain what a buffer is, how it works and how it affects living organisms. Learning Targets

 Occasionally, water breaks apart into hydrogen and hydroxide ions  An imbalance of these ions leads to pH of solutions  More H+ = acid  More OH- = base Disassociation of Water

Figure 3.10 pH Scale Battery acid Gastric juice, lemon juice Vinegar, wine, cola Beer Tomato juice Black coffee Rainwater Urine Saliva Pure water Human blood, tears Seawater Inside of small intestine Milk of magnesia Household ammonia Household bleach Oven cleaner Basic solution Neutral solution Acidic solution Neutral [H + ] = [OH  ] Increasingly Basic [H + ] < [OH  ] Increasingly Acidic [H + ] > [OH  ] H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ OH  H+H+ H+H+ H+H+ H+H+ H+H+ H+H+ H+H

2.I can describe how acids and bases affect living organisms. a.I can determine the relationship between H+ and OH- in acidic, basic, and neutral solutions. b.I can relate the relative amounts of H+ and OH- to the pH scale. c.I can explain the logarithmic connection the pH scale. d.I can explain what a buffer is, how it works and how it affects living organisms. Learning Targets

 Minimizes changes to pH in a solution  Example: carbonic acid in blood  If pH is too acidic: accepts access H+ ions  If pH is too basic: donates H+ ions  Living organisms must maintain homeostasis! Buffers