1. How many single covalent bonds can this phosphorus atom form? 02.01Q 1.1 2.2 3.3 4.4 5.5 6.6 7.7 8.8

2. 02.01A 1.1 2.2 3.3 4.4 5.5 6.6 7.7 8.8 How many single covalent bonds can this phosphorus atom form?

3. How many single covalent bonds can this phosphorus atom form? Answer: 3 Explanation: The innermost orbital can hold 2 electrons, but the outer orbitals can hold 8. Since phosphorus has 15 electrons, its innermost orbitals have 2 + 8 electrons, leaving 5 in the outermost orbital; thus there is room to share 3 more electrons. 02.01E

4. 1.Two electrons completely fill its outermost electron shell. 2.Eight electrons completely fill its outermost electron shell. 3.The outermost electron shell is half-empty. 4.Helium atoms react readily with oxygen. 5.Hydrogen atoms react to form helium. Why is a helium atom (atomic number = 2) more stable than a hydrogen atom (atomic number = 1)? 02.02Q

5. 1.Two electrons completely fill its outermost electron shell. 2.Eight electrons completely fill its outermost electron shell. 3.The outermost electron shell is half-empty. 4.Helium atoms react readily with oxygen. 5.Hydrogen atoms react to form helium. Why is a helium atom (atomic number = 2) more stable than a hydrogen atom (atomic number = 1)? 02.02A

6. Why is a helium atom (atomic number = 2) more stable than a hydrogen atom (atomic number = 1)? 02.02E Answer: Two electrons completely fill its outermost electron shell. Explanation: An atom is termed stable if its outermost electron shell is “full” of electrons. The first shell needs only two electrons to be full. The rest of the orbitals require 8 electrons to be full. Helium’s outermost shell (the first orbital) contains two electrons which is considered full for that orbital.

7. 1.A and B are stable. 2.C and D are stable. 3.A is stable but B is not. 4.D is stable but A, B, and C are not. 5.None of these atoms are stable. Indicate which of the figures at left depict stable atoms. 02.03Q

8. 1.A and B are stable. 2.C and D are stable. 3.A is stable but B is not. 4.D is stable but A, B, and C are not. 5.None of these atoms are stable. Indicate which of the figures at left depict stable atoms. 02.03A

9. Indicate which of the figures depict stable atoms. Answer: C and D are stable. Explanation: Atoms C and D are ions. They have lost or gained an electron in order to become stable (that is, to have 8 electrons in their outer shell). Atoms A and B do not have 8 electrons in their outer shell and are therefore unstable. 02.03E

10. Why are hydrophobic molecules, such as fats and oils, unable to dissolve in watery solutions? 3.Water cannot interact with hydrophobic molecules, such as fats and oils, because hydrophobic molecules form hydrogen bonds with each other, excluding the water. 4.Water molecules form hydrogen bonds with each other, excluding the hydrophobic molecules. 1.Water cannot interact with molecules that have polar covalent bonds, such as fats and oils. 2.Water cannot interact with molecules with ionic bonds, such as fats and oils. 02.04Q

11. Why are hydrophobic molecules, such as fats and oils, unable to dissolve in watery solutions? 3.Water cannot interact with hydrophobic molecules, such as fats and oils, because hydrophobic molecules form hydrogen bonds with each other, excluding the water. 4.Water molecules form hydrogen bonds with each other, excluding the hydrophobic molecules. 1.Water cannot interact with molecules that have polar covalent bonds, such as fats and oils. 2.Water cannot interact with molecules with ionic bonds, such as fats and oils. 02.04A

12. Why are hydrophobic molecules, such as fats and oils, unable to dissolve in watery solutions? 02.04E Answer: Water molecules form hydrogen bonds with each other, excluding the hydrophobic molecules. Explanation: Fats and oils do not contain polar covalent bonds, and water interacts strongly with molecules that have polar covalent bonds. Additionally, fats and oils do not contain ionic bonds. Hydrophobic molecules do not contain polar covalent bonds and, therefore, cannot form hydrogen bonds. This leaves choice four as the only correct answer.

13. 1. 100; fewer 2. 100; more 3. 2; fewer 4. 2; more A solution of pH 7 has ________ times _________ H+ ions than a solution of pH 9. 02.05Q

14. 1. 100; fewer 2. 100; more 3. 2; fewer 4. 2; more A solution of pH 7 has ________ times _________ H+ ions than a solution of pH 9. 02.05A

15. A solution of pH 7 has ________ times _________ H+ ions than a solution of pH 9. 02.05E Answer: 100; more Explanation: A solution of lower pH has more H+ ions; each unit on the pH scale represents a tenfold change in H+ concentration.

16. 1.hydrolysis. 2.dehydration synthesis of a disaccharide. The reaction shown below is an example of 02.06Q 3.synthesis of DNA. 4.breakdown of a fat molecule.

17. 1.hydrolysis. 2.dehydration synthesis of a disaccharide. The reaction shown below is an example of 02.06A 3.synthesis of DNA. 4.breakdown of a fat molecule.

18. Answer: dehydration synthesis of a disaccharide. Explanation: This picture shows a larger molecule being produced from two smaller molecules. This allows you to cross out choices 1 and 4 as possible answers. By taking a closer look at the picture, you see that the molecule being produced is a sugar with two rings (a disaccharide). The reaction shown below is an example of 02.06E

19. 1.oil; fat 2.chitin; lipids 3.RNA; DNA 4.amino acid; protein 5.hydrolysis; condensation Glucose is to starch as _______ is to _______. 02.07Q

20. 1.oil; fat 2.chitin; lipids 3.RNA; DNA 4.amino acid; protein 5.hydrolysis; condensation Glucose is to starch as _______ is to _______. 02.07A

21. Glucose is to starch as _______ is to _______. Answer: amino acid; protein Explanation: Monosaccharides of glucose are joined together to form a large polysaccharide such as starch. Subunits known as amino acids are joined together to form a large polymer known as a protein. None of the other answers have the monomer; polymer connection. 02.07E

22. 1.Naturally occurring fats contain a glycerol and three fatty acids. 2.Naturally occurring fats contain a glycerol, two fatty acids, and a phosphate group. The fat substitute Olestra contains a sucrose backbone with six to eight fatty acids attached. How is this different from a naturally occurring fat? 02.08Q 3.Naturally occurring fats contain a sucrose backbone and three fatty acid chains. 4.Olestra and natural fats have the same structure; they just have different tastes.

23. 1.Naturally occurring fats contain a glycerol and three fatty acids. 2.Naturally occurring fats contain a glycerol, two fatty acids, and a phosphate group. The fat substitute Olestra contains a sucrose backbone with six to eight fatty acids attached. How is this different from a naturally occurring fat? 02.08A 3.Naturally occurring fats contain a sucrose backbone and three fatty acid chains. 4.Olestra and natural fats have the same structure; they just have different tastes.

24. Answer: Naturally occurring fats contain a glycerol and three fatty acids. Explanation: This question tested your knowledge of the structure of a fat molecule. Refer to the picture at right, which also appears in your book. The fat substitute Olestra contains a sucrose backbone with six to eight fatty acids attached. How is this different from a naturally occurring fat? 02.08E

25. The diagram at right illustrates 02.09Q 1.the formation of a polysaccharide. 2.the four levels of protein structure. 3.the breakdown of a nucleic acid. 4.the synthesis of a saturated fat.

26. The diagram at right illustrates 02.09A 1.the formation of a polysaccharide. 2.the four levels of protein structure. 3.the breakdown of a nucleic acid. 4.the synthesis of a saturated fat.

27. Answer: the four levels of protein structure. Explanation: A chain of amino acids must fold into the correct structure in order to function as a given protein. Fats, polysaccharides, and nucleic acids are not subject to such specific levels of folding, organization, and structure. The diagram at right illustrates 02.09E

28. 1.RNA 2.Starch 3.Phospholipid 4.DNA 5.All of the above 6.Both 1 & 4 7.Both 2 & 3 The molecule at right could be 02.10Q

29. 1.RNA 2.Starch 3.Phospholipid 4.DNA 5.All of the above 6.Both 1 & 4 7.Both 2 & 3 The molecule at right could be 02.10A

30. Answer: Both 1 & 4 Explanation: The nucleotide building blocks of nucleic acids consist of a sugar, a phosphate group, and a nitrogen-containing base. Given this information, you can narrow down the answer choices to only nucleic acids, including DNA and RNA. Since the picture doesn’t specify the type of 5-carbon sugar, you would determine that it could be either DNA or RNA. The molecule at right could be 02.10E