2. 5/4/2015Mr. Ward Chapter 4 THE CHEMISTRY OF LIFE!

3. 5/4/2015Mr. Ward WATER n WATER IS AN ESSENTIAL INGREDIENT OF LIFE. n IT IS KNOWN AS THE UNIVERSAL SOLVENT. ITS SOLVENT ABILITIES COME FROM ITS POLAR NATURE. n MOST ALL CHEMICAL REACTIONS IN ORGANISMS OCCUR IN WATER.

4. Groups n 1. What is the chemical make-up of water? n 2. What type of bonds are present in water? 5/4/2015Mr. Ward

5. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Covalent Bonds n Covalent bonds form when two atoms share one or more pairs of valence electrons. –Give rise to discrete molecules.

6. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Chemistry of Water n Water molecule consists of an oxygen atom bound to two hydrogen atoms by two single covalent bonds. Copyright © McGraw-Hill Companies Permission required for reproduction or display

7. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Hydrogen Bonds n In a water molecule, both oxygen and hydrogen atoms attract shared electrons in the covalent bonds (electronegativity). –Shared electrons are thus more likely to be found near the oxygen nucleus than near the hydrogen nuclei. n Polar Molecule - Has distinct ends, each with a partial charge.

8. Group n Why is there unequal sharing of electrons in a water molecule? 5/4/2015Mr. Ward

9. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies

10. Water has cohesive and adhesive properties n 1. More than a cup? n 2. Pennies on a slide n 3. Plant transport n 4. Meniscus 5/4/2015Mr. Ward

11. Group n Explain the reason for the results in each of the demonstrations. 5/4/2015Mr. Ward

12. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies Copyright © McGraw-Hill Companies Permission required for reproduction or display

13. 5/4/2015Mr. Ward n IT HELPS TO MAINTAIN TEMPERATURE HOMEOSTASIS BY BEING ABLE TO ABSORB MUCH HEAT. n IN HUMANS WATER ACCOUNTS FOR ROUGHLY TWO-THIRDS OF OUR BODY WEIGHT.

14. Mind check n 1. Why does an ice cube float in water? n A. because the air bubbles in the ice make it lighter n B. because ice is a solid and water is a liquid n C. because ice has a lower density n D. because ice is packed tighter than water 5/4/2015Mr. Ward

15. n 2. At what temperature does water freeze? n A. 0 degrees centigrade n B. 100 degrees centigrade n C. 4 degrees centigrade n D. 32 degrees centigrade 5/4/2015Mr. Ward

16. n 3. Water is different than ice in that n A. they are made of different elements n B. ice has a rigid lattice structure n C. ice contains hydrogen bonds while water does not n D. water molecules in ice are more polar 5/4/2015Mr. Ward

17. n 4. The density of liquid water is 1.0 gm/cu.cm. The density of ice is closest to n A. 1.0 gm/cu.cm. n B. 0.93 gm/cu.cm. n C. 0.70 gm/cu.cm. n D. 1.1 gm/cu.cm. 5/4/2015Mr. Ward

18. n 5. Which of the following statement is not correct? n A. liquid water has a partially ordered structure n B. water molecule are in constant motion forming and breaking hydrogen bonds n C. ice has a rigid lattice structure 5/4/2015Mr. Ward

19. 5/4/2015Mr. Ward MIXTURES n MIXTURES OCCUR WHEN SUBSTANCES ARE PHYSICALLY MIXED WITHOUT FORMING NEW CHEMICAL BONDS. n PROPORTIONS OF SUBSTANCES VARY

20. 5/4/2015Mr. Ward MIXTURE DISTRIBUTION PATTERNS n HOMOGENEOUS - SAME THROUGHOUT n HETEROGENEOUS - DIFFERENT AMOUNTS THROUGHOUT

21. Group n 1. What are some types of mixtures? n 2 Give an least one example of each mixture. 5/4/2015Mr. Ward

22. 5/4/2015Mr. Ward SOLUTIONS n STABLE, HOMOGENEOUS MIXTURES, USUALLY LIQUIDS n SOLVENT n SOLUTE

23. 5/4/2015Mr. Ward SUSPENSIONS n A MIXTURE THAT SEPARATES ON STANDING

24. 5/4/2015Mr. Ward COLLOIDAL DISPERSION n MIXTURE IN WHICH THE DISPERSED PARTICLES ARE LARGE BUT DO NOT SETTLE OUT. n MAY OCCUR IN SOLIDS, LIQUIDS, OR GASES.

25. Group n What are some examples of colloids? Why are they colloids? 5/4/2015Mr. Ward

26. 5/4/2015Mr. Ward ACIDS, BASES AND SALTS n ACIDS ARE HYDROGEN DONORS n BASES ARE HYDROGEN ACCEPTORS n SALTS FORM WHEN A NEUTRALIZATION REACTION OCCURS BETWEEN AN ACID AND A BASE, NaCl IS AN EXAMPLE.

27. 5/4/2015Mr. Ward pH SCALE n SCALE GOES FROM 0 TO 14 n O-7 IS ACIDIC, 7 IS NEUTRAL, AND 7-14 IS BASIC n INDICATORS CHANGE COLORS WHEN DIFFERENT pH’S OCCUR

28. Raven - Johnson - Biology: 6th Ed. - All Rights Reserved - McGraw Hill Companies

29. Groups n What is the reason for the change in color of the solution in the Erlenmeyer flask? 5/4/2015Mr. Ward

30. 5/4/2015Mr. Ward ORGANIC VS INORGANIC COMPOUNDS

31. 5/4/2015Mr. Ward n 1. C, H, O, AND N MAKE UP 96.3% OF THE WEIGHT OF THE HUMAN BODY. n 2. INORGANIC COMPOUNDS ARE PRIMARILY THOSE COMPOUNDS THAT DO NOT CONTAIN CARBON, CARBON DIOXIDE AND WATER ARE INORGANIC.

32. 5/4/2015Mr. Ward n 3. ORGANIC COMPOUNDS CONTAIN CARBON, HYDROGEN, AND USUALLY OXYGEN. n 4. ORGANIC COMPOUNDS ARE SOMEHOW DIRECTLY ASSOCIATED WITH ORGANISMS.

33. 5/4/2015Mr. Ward CHARACTERISTICS OF CARBON

34. 5/4/2015Mr. Ward n 1. ATOMIC STRUCTURE OF CARBON –ATOMIC SYMBOL= C –ATOMIC NUMBER=6 –ATOMIC MASS =12 –ELECTRON DOT CONFIGURATION

35. Group n Draw the electron dot configuration for carbon on paper. 5/4/2015Mr. Ward

36. 5/4/2015Mr. Ward n 2. CARBON HAS THE ABILITY TO FORM 4 STRONG AND STABLE COVALENT BONDS. n 3. CARBON CAN FORM CHAINS OF ALMOST UNLIMITED LENGTH BY BONDING TO OTHER CARBON ATOMS.

37. 5/4/2015Mr. Ward n 4. CARBON MAY FORM SINGLE, DOUBLE, OR TRIPLE COVALENT BONDS. n 5. THE CARBON CHAINS MAY CLOSE ON THEMSELVES TO FORM RINGS.

38. 5/4/2015Mr. Ward POLYMERIZATION OF ORGANIC COMPOUNDS

39. 5/4/2015Mr. Ward n 1. THIS PROCESS OCCURS WHEN LARGE COMPOUNDS ARE CONSTRUCTED BY JOINING TOGETHER SMALLER COMPOUNDS. n 2. THE SMALLER COMPOUNDS ARE CALLED MONOMERS. n 3. THE LARGER COMPOUNDS ARE CALLED POLYMERS.

40. 5/4/2015Mr. Ward n 4. VERY LARGE POLYMERS ARE CALLED MACROMOLECULES.