Chapter 3: Water & Life

1. Chapter 3: Water & Life

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

3. Review: Polar Covalent & Hydrogen Bonds

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

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

6. What is the charge on this protein?

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

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

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

10. 2. Water Moderates Temperature • 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

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

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

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

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

15. Affect on Life Ice floats

16. Crash Course: Water- Liquid Awesome

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

18. Figure 3.10 pH Scale 0 1 Battery acid 2 Gastric juice, lemon juice H+ H+ H+ Vinegar, wine, cola OH 3 H+ Increasingly Acidic [H+] > [OH] H+ OH H+ H+ H+ 4 Tomato juice Acidic solution Beer Black coffee 5 Rainwater 6 Urine OH Saliva Neutral [H+] = [OH] OH 7 Pure water OH H+ H+ OH OH Human blood, tears H+ H+ H+ 8 Seawater Neutral solution Inside of small intestine 9 10 Increasingly Basic [H+] < [OH] Milk of magnesia OH OH 11 OH H+ OH Household ammonia OH OH OH H+ 12 Basic solution Household bleach 13 Oven cleaner 14

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

20. Buffers • 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!