Test Bank for Life: The Science of Biology, 11th Edition

Test Bank to accompany Life: The Science of Biology, Eleventh Edition Sadava • Hillis • Heller • Hacker Chapter 2: Small Molecules and the Chemistry of Life TEST BANK QUESTIONS Multiple Choice 1. An atom with _______ has an atomic mass of 14. a. 14 neutrons b. 14 electrons c. 7 neutrons and 7 electrons d. 7 protons and 7 electrons e. 6 protons and 8 neutrons Answer: e Learning Outcome: 2.1.1.a Describe the structure of an atom. Bloom’s Level: 3. Applying 2. Which statement about an atom is true? a. Only protons contribute significantly to the atom’s mass. b. Only neutrons contribute significantly to the atom’s mass. c. Only electrons contribute significantly to the atom’s mass. d. Both protons and neutrons together contribute significantly to the atom’s mass. e. Both protons and electrons together contribute significantly to the atom’s mass. Answer: d Learning Outcome: 2.1.1.a Describe the structure of an atom. Bloom’s Level: 1. Remembering 3. What is the difference between an atom and an element? a. An atom is made of protons, electrons, and (most of the time) neutrons; an element is composed of only one kind of atom. b. An element is made of protons, electrons, and (most of the time) neutrons; an atom is composed of only one kind of element. c. An atom does not contain electrons, whereas an element does. d. An atom contains protons and electrons, whereas an element contains protons, electrons, and neutrons. e. All atoms are the same, whereas elements differ in structure and properties. Answer: a Learning Outcome: 2.1.1.a Describe the structure of an atom. Bloom’s Level: 2. Understanding © 2017 Sinauer Associates, Inc. 4. In the history of the discovery of the parts of an atom, the neutron was discovered after the proton and electron. What property of a neutron made it more difficult than the proton or electron to discover? a. Diameter b. Location in the nucleus c. Mass d. Lack of charge e. Presence in isotopes Answer: d Learning Outcome: 2.1.2.a Compare and contrast the properties of protons, neutrons, and electrons. Bloom’s Level: 3. Applying 5. The number of protons in a neutral atom equals the number of a. electrons. b. neutrons. c. electrons plus neutrons. d. neutrons minus electrons. e. isotopes. Answer: a Learning Outcome: 2.1.3.a Explain why atoms typically have no overall electrical charge. Bloom’s Level: 1. Remembering 6. Which of the following statements about the atom is true? a. There are usually more protons than electrons in an atom because the negative charge of an electron is larger than the positive charge of a proton. b. The negative charge of an electron adds mass to an atom without influencing other properties. c. In an atom with a neutral charge, the number of electrons is equal to the number of protons. d. The number of electrons determines whether an atom of an element is radioactive. e. The energy level of electrons is higher in shells close to the nucleus of the atom. Answer: c Learning Outcome: 2.1.3.a Explain why atoms typically have no overall electrical charge. Bloom’s Level: 2. Understanding 7. A lithium atom contains three protons. For this atom to remain inert in an electric field, it must also contain a. three neutrons. b. three electrons. c. two neutrons and two electrons. d. no electrons. e. no neutrons. Answer:b Learning Outcome: 2.1.3.a Explain why atoms typically have no overall electrical charge. © 2017 Sinauer Associates, Inc. Bloom’s Level: 3. Applying 8. Refer to the table below. Four samples taken from an underground geologic site were analyzed in a chemistry lab. The table summarizes the elements found in greatest abundance in each sample. Which sample(s) could have originated from living sources? a. C only b. A and B c. B and C d. A and C e. B, C, and D Answer: c Learning Outcome: 2.1.4.a Compare the elements found in living tissue with elements found in nonliving matter. Bloom’s Level: 4. Analyzing 9. The six elements most common in organisms are a. calcium, iron, hydrogen, phosphorus, potassium, and oxygen. b. water, carbon, hydrogen, nitrogen, sodium, and oxygen. c. carbon, oxygen, hydrogen, phosphorus, sulfur, and nitrogen. d. nitrogen, carbon, iron, sulfur, calcium, and hydrogen. e. phosphorus, helium, carbon, potassium, hydrogen, and oxygen. Answer: c Learning Outcome: 2.1.4.a Compare the elements found in living tissue with elements found in nonliving matter. Bloom’s Level: 1. Remembering 10. The number of different natural elements found in the universe is closest to a. 18. b. 54. c. 86. d. 94. e. 146. Answer: d © 2017 Sinauer Associates, Inc. Learning Outcome: 2.1.4.a Compare the elements found in living tissue with elements found in nonliving matter. Bloom’s Level: 1. Remembering 11. The best reference source for the atomic number and mass number of an element is a. a good chemistry text. b. a dictionary. c. the periodic table. d. a general physics book. e. a good biology text. Answer: c Learning Outcome: 2.1.5.b Use the periodic table to compare and contrast the atomic structures of different elements. Bloom’s Level: 1. Remembering 12. Which element has a higher atomic mass than phosphorus? a. Hydrogen b. Oxygen c. Sodium d. Magnesium e. Calcium Answer: e Learning Outcome: 2.1.5.b Use the periodic table to compare and contrast the atomic structures of different elements. Bloom’s Level: 4. Analyzing 13. According to the periodic table, which element has the same number of outer shell (valence) electrons as oxygen? a. Calcium b. Nitrogen c. Fluorine d. Sodium e. Sulfur Answer: e Learning Outcome: 2.1.5.b Use the periodic table to compare and contrast the atomic structures of different elements. Bloom’s Level: 3. Applying 14. According to the periodic table, the compound that sulfur forms with hydrogen is most like a. NH4+. b. NH3. c. H2O. d. HF. e. HCl. Answer: c © 2017 Sinauer Associates, Inc. Learning Outcome: 2.1.5.b Use the periodic table to compare and contrast the atomic structures of different elements. Bloom’s Level: 4. Analyzing 15. Carbon and silicon have the same number of a. protons. b. valence (outershell) electrons. c. neutrons. d. electrons. e. protons and neutrons. Answer: b Learning Outcome: 2.1.5.b Use the periodic table to compare and contrast the atomic structures of different elements. Bloom’s Level: 3. Applying 16. Which pair has similar chemical properties? a. 12C and 14C b. 12C and 40Ca c. 16O and 16N d. 1H and 22Na e. 18O and 45Ca Answer: a Learning Outcome: 2.1.5.b Use the periodic table to compare and contrast the atomic structures of different elements. Bloom’s Level: 2. Understanding 17. The atomic number of an element is the same as the number of _______ in each atom. a. neutrons b. neutrons plus electrons c. neutrons plus protons d. protons e. protons plus electrons Answer: d Learning Outcome: 2.1.6.a Analyze the number of protons and neutrons present in an atom from its atomic number and mass number. Bloom’s Level: 1. Remembering 18. The mass number of an atom is determined primarily by the _______ it contains. a. number of electrons b. number of protons c. sum of the number of protons and the number of electrons d. sum of the number of protons and the number of neutrons e. number of charges Answer: d © 2017 Sinauer Associates, Inc. Learning Outcome: 2.1.6.a Analyze the number of protons and neutrons present in an atom from its atomic number and mass number. Bloom’s Level: 1. Remembering 19. A stable isotope of phosphorus has an atomic number of 15 and an atomic mass of 31. How many neutrons does this isotope of phosphorus have? a. 14 b. 16 c. 30 d. 31 e. 46 Answer: b Learning Outcome: 2.1.6.a Analyze the number of protons and neutrons present in an atom from its atomic number and mass number. Bloom’s Level: 3. Applying 20. Carbon-12 is the most abundant isotope of carbon on Earth. Carbon-13 makes up about 1 percent of Earth’s carbon atoms and is useful for radio imaging. Which of the following is true? a. Carbon-13 has more protons than carbon-12. b. Carbon-13 has more neutrons than carbon-12. c. Carbon-13 has more electrons than carbon-12. d. Carbon-13 has an electronic configuration that is different from that of carbon-12. e. Carbon-13 has an equal number of protons and neutrons. Answer: b Learning Outcome: 2.1.6.a Analyze the number of protons and neutrons present in an atom from its atomic number and mass number. Bloom’s Level: 3. Applying 21. Nitrogen-14 and nitrogen-15 are isotopes. Nitrogen-15 is used to determine protein structure. Which of the following is true? a. Nitrogen-15 has more neutrons than nitrogen-14. b. Nitrogen-15 has more protons than nitrogen-14. c. Nitrogen-15 has more electrons than nitrogen-14. d. Nitrogen-15 has an electronic configuration that is different from that of nitrogen-14. e. Nitrogen-15 has an equal number of protons and neutrons. Answer: a Learning Outcome: 2.1.6.a Analyze the number of protons and neutrons present in an atom from its atomic number and mass number. Bloom’s Level: 3. Applying 22. Drawings of hydrogen, deuterium, and tritium would contain different numbers of a. protons. b. neutrons. c. electrons. d. nuclei. © 2017 Sinauer Associates, Inc. e. electron shells. Answer: b Learning Outcome: 2.1.7.a Draw the atomic structures of three isotopes of hydrogen. Bloom’s Level: 3. Applying 23. P and P have virtually identical chemical and biological properties because they have the same a. half-life. b. number of neutrons. c. atomic weight. d. mass number. e. number of electrons. Answer: e Learning Outcome: 2.1.9.a Explain the role that the outermost electron shell plays in determining how an atom may combine with other atoms. Bloom’s Level: 3. Applying 24. What part of the atom determines how the atom reacts chemically? a. Proton b. Neutron c. Electron d. Innermost shell e. Nucleus Answer: c Learning Outcome: 2.1.9.a Explain the role that the outermost electron shell plays in determining how an atom may combine with other atoms. Bloom’s Level: 1. Remembering 25. The ability of an atom to combine with other atoms is determined by the atom’s a. atomic weight. b. ability to form isomers. c. number and distribution of electrons. d. nuclear configuration. e. mass number. Answer: c Learning Outcome: 2.1.9.a Explain the role that the outermost electron shell plays in determining how an atom may combine with other atoms. Bloom’s Level: 2. Understanding 26. An atom is most stable when a. it can have one unpaired valence electron, allowing it to follow the octet rule. b. it can share electrons with other atoms to form an uneven number of pairs of electrons. c. it has eight electrons. d. it can fill its outermost shell by sharing electrons or by gaining or losing one or more electrons until it is filled. e. its outermost electron shell follows the quartet rule. © 2017 Sinauer Associates, Inc. Answer: d Learning Outcome: 2.1.9.a Explain the role that the outermost electron shell plays in determining how an atom may combine with other atoms. Bloom’s Level: 2. Understanding 27. Which element is the most chemically reactive? a. Carbon b. Helium c. Neon d. Argon e. Krypton Answer: a Learning Outcome: 2.1.9.b Explain how elements can be grouped according to their chemical properties in a periodic fashion. Bloom’s Level: 2. Understanding 28. All of the elements listed below follow the octet rule except a. hydrogen. b. chlorine. c. carbon. d. sodium. e. nitrogen. Answer: a Learning Outcome: 2.1.9.b Explain how elements can be grouped according to their chemical properties in a periodic fashion. Bloom’s Level: 2. Understanding 29. Which of the elements listed below requires two additional electrons to fill the outermost electron shell? a. Lithium b. Carbon c. Nitrogen d. Oxygen e. Fluorine Answer: d Learning Outcome: 2.1.9.b Explain how elements can be grouped according to their chemical properties in a periodic fashion. Bloom’s Level: 3. Applying 30. Which correctly shows the relative strengths of chemical bonds in decreasing order? a. Covalent, ionic, hydrogen, van der Waals forces b. Ionic, covalent, hydrogen, van der Waals forces c. van der Waals forces, covalent, ionic, hydrogen d. Hydrogen, covalent, van der Waals forces, ionic e. Ionic, covalent, van der Waals forces, hydrogen Answer: a © 2017 Sinauer Associates, Inc. Learning Outcome: 2.2.1.a Identify examples of chemical bonds. Bloom’s Level: 2. Understanding 31. Which atom usually has the greatest number of covalent bonds with other atoms? a. Carbon b. Oxygen c. Sulfur d. Hydrogen e. Nitrogen Answer: a Learning Outcome: 2.2.2.a Give an example of a covalent bond and show how electrons are involved in formation of the bond. Bloom’s Level: 1. Remembering 32. In a hydrogen molecule, the two atoms are held together by a. hydrogen bonds. b. a shared pair of electrons. c. van der Waals forces. d. ionic attractions. e. differences in electronegativity. Answer: b Learning Outcome: 2.2.2.a Give an example of a covalent bond and show how electrons are involved in formation of the bond. Bloom’s Level: 2. Understanding 33. Which statement is true? a. Carbon makes the same number of covalent bonds as phosphorus does. b. Oxygen makes more covalent bonds than sulfur does. c. Sulfur makes more covalent bonds than carbon does. d. Hydrogen makes more covalent bonds than carbon does. e. Oxygen makes fewer covalent bonds than nitrogen does. Answer: e Learning Outcome: 2.2.2.a Give an example of a covalent bond and show how electrons are involved in formation of the bond. Bloom’s Level: 3. Applying 34. Oxygen forms _______ covalent bond(s), carbon forms _______, and hydrogen forms _______. a. one; four; one b. four; four; four c. two; four; none d. two; four; one e. two; two; two Answer: d Learning Outcome: 2.2.2.a Give an example of a covalent bond and show how electrons are involved in formation of the bond. © 2017 Sinauer Associates, Inc. Bloom’s Level: 1. Remembering 35. Refer to the Bohr model of methane shown below. Which statement about this structure is true? a. All bonds are ionic bonds. b. All bonds are hydrogen bonds. c. All bonds contain paired electrons from carbon. d. All bonds contain paired electrons from hydrogen. e. All bonds contain paired electrons shared between carbon and hydrogen. Answer: e Learning Outcome: 2.2.2.a Give an example of a covalent bond and show how electrons are involved in formation of the bond. Bloom’s Level: 3. Applying 36. A double covalent chemical bond represents the sharing of _______ electron(s). a. one b. two c. three d. four e. six Answer: d Learning Outcome: 2.2.2.a Give an example of a covalent bond and show how electrons are involved in formation of the bond. Bloom’s Level: 1. Remembering 37. Two carbon atoms held together in a double covalent bond share _______ electron(s). a. one b. two c. four d. six e. eight Answer: c © 2017 Sinauer Associates, Inc. Learning Outcome: 2.2.2.a Give an example of a covalent bond and show how electrons are involved in formation of the bond. Bloom’s Level: 2. Understanding 38. Differences in the electronegativity of atoms that share electronsin a bond are involved in a. a polar covalent bond. b.an ionic bond. c. a hydrogen bond. d. van der Waals forces. e. hydrophobic interactions. Answer: a Learning Outcome: 2.2.4.a Identify examples of polar covalent and nonpolar covalent bonds. Bloom’s Level: 2. Understanding 39. The two covalent bonds in a water molecule are polar because a. oxygen is more electronegative than hydrogen. b. oxygen and hydrogen have similar electronegativities. c. oxygen is less electronegative than hydrogen. d. water is a small molecule. e. water is hydrophilic. Answer: a Learning Outcome: 2.2.4.a Identify examples of polar covalent and nonpolar covalent bonds. Bloom’s Level: 2. Understanding 40. Which statement about ionic and covalent bonds is true? a. An ionic bond is stronger than a covalent bond. b. Compared with an ionic bond, a nonpolar covalent bond has more equal electron sharing. c. An ionic bond is almost identical to a nonpolar covalent bond. d. Ionic bonds vary in length, but covalent bonds are all the same length. e. An ionic bond can have multiple bonds, but a covalent bond cannot. Answer: b Learning Outcome: 2.2.4.a Identify examples of polar covalent and nonpolar covalent bonds; 2.2.6.a Give an example of an ionic attraction and show how electrons are involved in its formation. Bloom’s Level: 2. Understanding 41. Refer to the figure below. The figure shows the molecular structure of carbon dioxide. Carbon dioxide is nonpolar, © 2017 Sinauer Associates, Inc. whereas water is polar. Which of the true statements below explains these differences? a. Carbon dioxide does not contain any polar covalent bonds, whereas water does. b. Carbon dioxide contains only double bonds, whereas water contains only single bonds. c. Carbon dioxide is a linear molecule, whereas water has a bent shape. d. Carbon dioxide contains carbon atoms, whereas water does not. e. Carbon and oxygen do not differ greatly in electronegativity, whereas hydrogen and oxygen do. Answer: c Learning Outcome: 2.2.5.a Explain why water is a polar molecule. Bloom’s Level: 5. Evaluating 42. The ball-and-stick structure of methane (CH4) shows that a. the molecule is flat. b. the molecule is not polar. c. all bonds are hydrogen bonds. d. all bond angles are different. e. all bond lengths are different. Answer: b Learning Outcome: 2.2.5.a Explain why water is a polar molecule. Bloom’s Level: 4. Analyzing 43. All of the following are nonpolar except a. O2. b. N2. c. CH4. d. NaCl. e. H2. Answer: d Learning Outcome: 2.2.5.a Explain why water is a polar molecule. Bloom’s Level: 3. Applying 44. When magnesium (Mg) bonds with another element, it a. gains two electrons from the other element. b. shares four electrons with the other element. c. loses two electrons to the other element. d. forms a hydrogen bond. e. gains six electrons from the other element. Answer: c Learning Outcome: 2.2.6.a Give an example of an ionic attraction and show how electrons are involved in its formation. Bloom’s Level: 3. Applying 45. A covalent bond is formed by the sharing of _______ between atoms, whereas an ionic bond is formed by the _______. a. neutrons; sharing of electrons b. electrons; electric attraction between two neutral atoms © 2017 Sinauer Associates, Inc. c. protons; electric attraction between two neutral atoms d. protons; sharing of electrons e. electrons; transfer of electrons from one atom to another Answer: e Learning Outcome: 2.2.6.a Give an example of an ionic attraction and show how electrons are involved in its formation. Bloom’s Level: 2. Understanding 46. Particles that have a net negative charge are called a. electronegative. b. cations. c. anions. d. acids. e. bases. Answer: c Learning Outcome: 2.2.6.a Give an example of an ionic attraction and show how electrons are involved in its formation. Bloom’s Level: 1. Remembering 47. Which compound is held together by ionic bonds? a. Water b. Sugar c. Sodium chloride d. Methane e. Ammonia Answer: c Learning Outcome: 2.2.6.a Give an example of an ionic attraction and show how electrons are involved in its formation. Bloom’s Level: 1. Remembering 48. Hydrogen bonds a. form between two hydrogen atoms. b. form only between hydrogen and oxygen atoms within a molecule. c. form only between a weak electronegative atom and hydrogen. d. involve a transfer of electrons. e. form weak interactions but can provide structural stability when many are found in a single molecule. Answer: e Learning Outcome: 2.2.7.a Draw an example of a hydrogen bond and explain how it forms. Bloom’s Level: 2. Understanding 49. Hydrogen bonds are attractions a. between oppositely charged ions. b. between atoms, resulting in electron sharing. c. between cations. © 2017 Sinauer Associates, Inc. d. between atoms, each with partial electrical charges. e. that rely on hydrophobic interactions. Answer: d Learning Outcome: 2.2.7.a Draw an example of a hydrogen bond and explain how it forms. Bloom’s Level: 1. Remembering 50. Cholesterol is a lipid most often found in cell membranes. It is composed primarily of carbon and hydrogen atoms and has the following chemical formula: C27H46O. Based on this information, one would expect cholesterol to be a. insoluble in water. b. a highly polar molecule. c. a cation. d. an anion. e. insoluble in hexane. Answer: a Learning Outcome: 2.2.8.a Distinguish between hydrophilic and hydrophobic interactions using examples. Bloom’s Level: 3. Applying 51. Refer to the figure below showing the chemical structures of several molecules. Which pair of molecules is most likely to be miscible (each soluble in the other)? a. Octane and water b. Water and methanol c. Amino acid and octane d. Methanol and octane e. Amino acid and methanol Answer: b © 2017 Sinauer Associates, Inc. Learning Outcome: 2.2.8.a Distinguish between hydrophilic and hydrophobic interactions using examples. Bloom’s Level: 4. Analyzing 52. A van der Waals interaction is an attraction between a. the electrons and the nucleus of one molecule. b. two nonpolar molecules, due to the exclusion of water. c. the electrons of one molecule and the protons of a nearby molecule. d. two adjacent nonpolar molecules, due to variations in their electron distribution. e. two polar molecules, because they are surrounded by water molecules. Answer: d Learning Outcome: 2.2.9.a Identify instances in which van der Waals forces are important. Bloom’s Level: 2. Understanding 53. Carbon-14 is a radioactive isotope of carbon. When an organism is alive, the total amount of carbon-14 in the organism’s body remains constant. As soon as the organism dies, the amount of carbon-14 begins to decrease in a predictable way. This provides evidence for which statement about living organisms? a. Different organisms have different life-spans. b. Living organisms are dynamic and constantly exchanging matter with the environment. c. There is a huge diversity of life-forms represented among the organisms living today. d. All living organisms are composed of cells. e. Living organisms pass on biological information to their offspring. Answer: b Learning Outcome: 2.3.1.a Justify the claim that living organisms are dynamic. Bloom’s Level: 5. Evaluating 54. A biologist is conducting experiments on human muscle and collects a variety of data, listed below. Which type of data would provide evidence for the claim that living organisms are chemically dynamic? a. Amount of force generated by a muscle fiber b. Length of a muscle fiber c. Elemental composition of a muscle fiber d. Rate of metabolism of glucose by a muscle fiber e. Duration of contraction of a muscle fiber Answer: d Learning Outcome: 2.3.1.a Justify the claim that living organisms are dynamic. Bloom’s Level: 3. Applying 55. A chemist measures the masses of two substances separately, then combines them in a reaction flask and heats the mixture. After several minutes, the chemist cools the flask and measures the mass of the contents. The final mass of the contents is less than the sum of the masses of the two substances placed in the flask before heating. Which statement provides a possible explanation for this observation? © 2017 Sinauer Associates, Inc. a. Physical changes in the two starting substances resulted in products with less combined mass than the starting substances. b. Heating caused the substances to melt, which resulted in a change in overall volume and mass. c. The two starting substances absorbed energy from the heat, which destroyed some of the atoms making up the substances. d. Only one product was formed from the combination of two reactants, resulting in less overall mass at the end. e. The two starting substances underwent chemical change to produce two products, one of which was a gas. Answer: e Learning Outcome: 2.3.2.a Describe changes taking place during a chemical reaction. Bloom’s Level: 5. Evaluating 56. Refer to the oxidation-reduction reaction below. Fe + Cu2+ Cu + Fe2+ Thisreaction occurs spontaneously when a strip of iron metal is placed into a solution of copper sulfate dissolved in water. During the reaction, iron metal is oxidized to form a cation, and copper ion is reduced to form copper metal. Which statement describes the change taking place? a. The change is not a chemical change because no covalent bonds were broken and new ones formed. b. The change is not a chemical change because there were too few elements involved. c. The change is a chemical change because the products differ chemically from the reactants. d. The change is a chemical change because it occurred spontaneously. e. The change is a chemical change because there was no overall change in mass. Answer: c Learning Outcome: 2.3.2.a Describe changes taking place during a chemical reaction. Bloom’s Level: 5. Evaluating 57. Refer to the figure showing reactants before chemical change occurs. Which diagram could represent the products of this change? a. b. © 2017 Sinauer Associates, Inc. c. d. e. Answer: e Learning Outcome: 2.3.3.a Compare the products and reactants of a chemical reaction. Bloom’s Level: 4. Analyzing 58. Refer to the figure below. Which statement about the figure is true? a. It shows a chemical change because the products differ from the reactants. b. It shows a chemical change because the three molecules were transformed into two molecules. c. It shows a chemical change because energy was released as a result of the change. d. It does not accurately show a chemical change because the numbers of atoms on the two sides of the arrow differ. e. It does not accurately show a chemical change because energy is shown on the wrong side of the arrow. Answer: d Learning Outcome: 2.3.3.a Compare the products and reactants of a chemical reaction. Bloom’s Level: 4. Analyzing 59. Some reactions, such as the decomposition of nitroglycerin in dynamite, release large amounts of energy in the form of heat. Others, such as those taking place inside cells, release much smaller amounts of heat. Which statement is true about these reactions? a. The total amount of energy involved in the cellular reactions is conserved, but new energy is created during the explosive reaction involving nitroglycerin. b. Though a larger overall change in energy occurs in the nitroglycerin reaction, the total amount of energy present before and after each reaction does not change. c. Cells use up energy, causing an overall decrease in the total amount of energy present before cellular reactions, while nonliving things, such as dynamite, do not. © 2017 Sinauer Associates, Inc. d. Both living cells and nonliving things, such as dynamite, cause an overall loss of energy when they release heat during reactions. e. Only living things conserve energy from their reactions in the form of chemical bond energy, while nonliving things, such as dynamite, lose energy when they react. Answer: b Learning Outcome: 2.3.4.a Explain how the law of conservation of energy applies to chemical reactions. Bloom’s Level: 3. Applying 60. Which statement about biochemical reactions is false? a. They obey the rules of chemistry and physics. b. They must always balance the number of atoms in the reactants and the products. c. They can create new energy during the reaction. d. They can store energy in the form of a covalent bond. e. They can change the form of energy found in the cell. Answer: c Learning Outcome: 2.3.4.a Explain how the law of conservation of energy applies to chemical reactions. Bloom’s Level: 2. Understanding 61. Refer to the reaction shown. C3H8 + 5 O2 3 CO2 + 4 H2O + energy Which statement about the reaction is true? a. O2 is a product. b. Chemical bonds are conserved during the reaction. c. The same atoms are present before and after the reaction. d. A net input of energy is needed for this reaction. e. The products are similar to the reactants. Answer: c Learning Outcome: 2.3.4.b Demonstrate an example to show that chemical reactions obey the law of conservation of matter. Bloom’s Level: 3. Applying 62. Refer to the balanced chemical equation below. CH4 + 2O2  CO2 +2H2O + 890 kJ Which graph represents the energy changes accompanying this reaction? a. © 2017 Sinauer Associates, Inc. b. c. d. e. Answer: d Learning Outcome: 2.3.5.a Explain how energy is involved in a chemical reaction. Bloom’s Level: 3. Applying 63. Which observation makes a strong case that the study of water and its properties is relevant to the study of structural biology? a. Corals are marine animals that live in close association with photosynthetic algae that supply the corals with a source of food. b. Some Arctic fish produce antifreeze proteins to prevent ice crystals from forming in their cells. c. Animals that live in caves their entire lives rely on nutrients brought into their habitats by running water or by other organisms. d. Ice loses mass as water molecules go from the solid state directly to the gas state. e. Lake ecosystems can be destroyed by chemical fertilizers carried from farmland into lakes in rain runoff. Answer: b © 2017 Sinauer Associates, Inc. Learning Outcome: 2.4.1.a Explain why the study of water and its properties is relevant to the study of living organisms. Bloom’s Level: 3. Applying 64. Which statement explains why ice floats in liquid water? a. As water molecules go from the liquid to the solid state, their rate of motion decreases. b. Water molecules maintain the same bent shape in liquid and solid states. c. The ordered lattice structure of water molecules in ice is maintained by hydrogen bonds. d. The arrangement of water molecules in ice results in fewer molecules per unit volume than in liquid water. e. Water molecules maintain the same mass as they transition from the liquid to the solid state. Answer: d Learning Outcome: 2.4.2.a Justify the difference in densities of ice and liquid water. Bloom’s Level: 3. Applying 65. Ice floats because the ice crystals a. contain fewer water molecules per volume than the liquid water. b. are more dense than liquid water. c. form heat, which makes water expand. d. can move quickly and therefore can float. e. have a high surface tension. Answer: a Learning Outcome: 2.4.2.a Justify the difference in densities of ice and liquid water. Bloom’s Level: 2. Understanding 66. Which characteristic of water contributes most to the relatively constant temperatures of the oceans? a. Water has the ability to ionize slightly. b. Water has a high specific heat. c. Salt water has low surface tension. d. Salt water is denser than freshwater. e. Water requires a small amount of heat energy to raise its temperature. Answer: b Learning Outcome: 2.4.3.a Explain how the structure of water can be used to understand why water temperature changes slowly under the same conditions that causes the temperatures of other substances to change rapidly. Bloom’s Level: 2. Understanding 67. In the summer, ice is used to cool beverages primarily because it a. floats. b. is inexpensive. c. does not affect taste. d. is composed only of water. e. absorbs a lot of heat as it melts. © 2017 Sinauer Associates, Inc. Answer: e Learning Outcome: 2.4.3.a Explain how the structure of water can be used to understand why water temperature changes slowly under the same conditions that causes the temperatures of other substances to change rapidly. Bloom’s Level: 3. Applying 68. A car sitting in the sun on a hot summer day becomes very hot to the touch. Water in a bucket sitting next to the car under the same conditions for the same length of time feels cool to the touch. Which statement explains this difference? a. Radiant energy goes into breaking the forces of attraction between water molecules before increasing their rate of motion. b. Radiant energy is reflected off the surface of water rather than being absorbed by the water molecules. c. Radiant energy cannot easily penetrate water because of its density and is therefore not absorbed readily. d. Radiant energy is absorbed poorly by liquids, compared with solids. e. Radiant energy is absorbed by certain elements more readily than by other elements. Answer: a Learning Outcome: 2.4.3.a Explain how the structure of water can be used to understand why water temperature changes slowly under the same conditions that cause the temperatures of other substances to change rapidly. Bloom’s Level: 3. Applying 69. Refer to the figures below. The correct ranking of these compounds in order of lowest to highest heat capacity per mole of compound is B < A ionic attraction > hydrogen bond > hydrophobic interaction > van der Waals. b. Covalent bond > ionic attraction = hydrogen bond > hydrophobic interaction > van der Waals. c. Covalent bond < ionic attraction < hydrogen bond < hydrophobic interaction < van der Waals. d. Covalent bond < ionic attraction = hydrogen bond < hydrophobic interaction < van der Waals. e. Covalent bond < ionic attraction = van der Waals < hydrophobic interaction < hydrogen bond. Answer: b Hint: Check Table 2.1 to compare the ranges of bond energies that characterize the different types of bonds. Learning Outcome: 2.2.3.a Explain why covalent bonds are so strong. Bloom’s Level: 4. Analyzing Difficulty Level: Difficult © 2017 Sinauer Associates, Inc. 30. What type of chemical bond connects the two carbon atoms in the molecule shown below? a. Nonpolar covalent bond b. Asymmetric bond c. Polar covalent bond d. Hydrogen bond e. Double covalent bond Answer: a Hint: How does the bonding of two atoms of the same element affect the polarity of a bond? Learning Outcome: 2.2.4.a Identify examples of polar covalent and nonpolar covalent bonds. Bloom’s Level: 3. Applying Difficulty Level: Moderate 31. The electronegativity of an atom is a relative measure of the a. number of electrons in an atom. b. number of electrons in the atom’s outermost electron shell. c. difference between the number of atoms and the number of protons. d. affinity an atom has for electrons and its ability to capture additional electrons. e. affinity an atom has for protons and its ability to capture additional protons. Answer: d Hint: Remember that the attractive force exerted on electrons by an atom’s nucleus varies depending on the number of protons in the nucleus. Learning Outcome: 2.2.4.a Identify examples of polar covalent and nonpolar covalent bonds. Bloom’s Level: 1. Remembering Difficulty Level: Easy 32. Which covalent bond is most polar? a. Nitrogen–oxygen b. Carbon–oxygen c. Hydrogen–oxygen d. Nitrogen–hydrogen e. Carbon–hydrogen Answer: c Hint: Consider the differences in electronegativities of the atoms. Learning Outcome: 2.2.4.a Identify examples of polar covalent and nonpolar covalent bonds. Bloom’s Level: 3. Applying Difficulty Level: Difficult © 2017 Sinauer Associates, Inc. 33. Five statements describing water are given below. Which could best be used to explain why water is polar? a. The water molecule is composed of three atoms held together by two covalent bonds. b. The water molecule contains oxygen and hydrogen. c. The two O–H bonds in water are oriented such that the molecule has a bent shape. d. The oxygen atom is the central atom in a water molecule. e. The two O–H bonds in a water molecule are identical. Answer: c Hint: Remember that each O–H bond is polar, but the shape of the molecule determines how this characteristic affects the overall polarity of the molecule. Learning Outcome: 2.2.5.a Explain why water is a polar molecule. Bloom’s Level: 5. Evaluating Difficulty Level: Moderate 34. The figures below have all been used to represent a water molecule. Which could best be used to explain why water is polar? a. b. c. d. e. Answer: c Hint: How are bond angles important in allowing polar bonds to contribute to forming a polar molecule? Learning Outcome: 2.2.5.a Explain why water is a polar molecule. Bloom’s Level: 5. Evaluating © 2017 Sinauer Associates, Inc. Difficulty Level: Moderate 35. How does the ionic compound magnesium chloride form? a. A magnesium atom loses one electron, a chlorine atom gains one electron, and an ionic bond forms between the chloride ion and the magnesium ion. b. A magnesium atom loses two electrons, two chlorine atoms each gain one electron, and an ionic bond forms between each chloride ion and the magnesium ion. c. Two magnesium atoms each lose one electron, two chlorine atoms each gain one electron, and an ionic bond forms between each chloride ion and each magnesium ion. d. A chlorine atom loses one electron, a magnesium atom gains one electron, and an ionic bond forms between the chloride ion and the magnesium ion. e. Two chlorine atoms each lose one electron, a magnesium atom gains two electrons, and an ionic bond forms between each chloride ion and the magnesium ion. Answer: b Hint: Check the periodic table to decide how each element gains or loses electrons and how many electrons are gained or lost. Learning Outcome: 2.2.6.a Give an example of an ionic attraction and show how electrons are involved in its formation. Bloom’s Level: 3. Applying Difficulty Level: Moderate 36. Refer to the figure below. Does this figure accurately show how the ionic compound lithium oxide forms? a. Yes, because it shows two atoms forming ions that attract one another. b. Yes, because it shows how lithium and oxygen share electrons to form a bond. c. No, because lithium should gain electrons from oxygen, not the other way around, as shown. d. No, because oxygen has an incomplete outer shell and needs an electron from a second lithium atom. e. No, because the figure does not show how lithium and oxygen share electrons. Answer: d Hint: Remember that when they form ions, atoms gain or lose as many electrons as needed to fill their valence shells. © 2017 Sinauer Associates, Inc. Learning Outcome: 2.2.6.a Give an example of an ionic attraction and show how electrons are involved in its formation. Bloom’s Level: 5. Evaluating Difficulty Level: Difficult 37. A(n) _______ bond is created by a(n) _______ attraction between two _______. a. ionic; electrical; ions b. cation; ionic; atoms c. anion; ionic; molecules d. ionic; van der Waals; ions e. anion; cation; atoms Answer: a Hint: Remember that particles of opposite charges attract one another in forming one kind of chemical bond. Learning Outcome: 2.2.6.a Give an example of an ionic attraction and show how electrons are involved in its formation. Bloom’s Level: 2. Understanding Difficulty Level: Easy 38. A cation has the opposite charge from a(n) a. hydrophilic interaction. b. anion. c. nonpolar bond. d. ionic interaction. e. complex ion. Answer: b Hint: Remember that a cation is a positively charged ion. Learning Outcome: 2.2.6.aGive an example of an ionic attraction and show how electrons are involved in its formation. Bloom’s Level: 1. Remembering Difficulty Level: Easy 39. Which figure shows an example of a hydrogen bond? a. b. c. © 2017 Sinauer Associates, Inc. d. e. Answer: c Hint: Remember that hydrogen bonds are not covalent bonds. Learning Outcome: 2.2.7.a Draw an example of a hydrogen bond and explain how it forms. Bloom’s Level: 3. Applying Difficulty Level: Easy 40. Refer to the figure below. Two molecules are shown. Where is it most likely that a hydrogen bond would form? a. Between one of the hydrogen atoms in acetone and the oxygen atom in water b. Between one of the hydrogen atoms in acetone and one of the hydrogen atoms in water c. Between the oxygen atom in acetone and the oxygen atom in water d. Between the oxygen atom in acetone and one of the hydrogen atoms in water e. Between the carbon atom in acetone and one of the hydrogen atoms in water Answer: d Hint: Remember that hydrogen bonds form whenever a highly polar bond containing a hydrogen atom exists. This situation creates a hydrogen atom that has a strong partial positive charge. Learning Outcome: 2.2.7.a Draw an example of a hydrogen bond and explain how it forms. Bloom’s Level: 3. Applying Difficulty Level: Moderate 41. Refer to the figure below. © 2017 Sinauer Associates, Inc. The figure shows the molecular structure of methanol. One type of hydrogen bond has been observed to form between molecules of methanol. Which diagram shows the most likely set of atoms involved in these hydrogen bonds? a. b. c. d. e. Answer: a Hint: Remember that hydrogen bonds form whenever a highly polar bond containing a hydrogen atom exists. This situation creates a hydrogen atom that has a strong partial positive charge. © 2017 Sinauer Associates, Inc. Learning Outcome: 2.2.7.a Draw an example of a hydrogen bond and explain how it forms. Bloom’s Level: 3. Applying Difficulty Level: Difficult 42. Vegetable oil is composed of long-chain hydrocarbon molecules. Vegetable oil and water do not mix but form separate layers. Which statement describes the interactions between molecules in this case? a. The water molecules and the hydrocarbon molecules interact with their own kind through hydrogen bonding, but they do not interact with each other. b. The water molecules and the hydrocarbon molecules interact with their own kind through hydrophilic interactions, but they do not interact with each other. c. The water molecules and the hydrocarbon molecules interact with their own kind through hydrophobic interactions, but they do not interact with each other. d. The water molecules interact through hydrophobic interactions, and the hydrocarbon molecules interact through hydrophilic interactions. e. The water molecules interact through hydrophilic interactions, and the hydrocarbon molecules interact through hydrophobic interactions. Answer: e Hint: What type of intermolecular interactions would you expect to observe between nonpolar long-chain hydrocarbon molecules? Learning Outcome: 2.2.8.a Distinguish between hydrophilic and hydrophobic interactions using examples. Bloom’s Level: 3. Applying Difficulty Level: Moderate 43. Refer to the figure below. The figure shows four examples of molecular interactions in biological samples. Can any of these be used as examples of hydrophilic or hydrophobic interactions? a. 1, 2, and 3 hydrophilic; 4 hydrophobic b. 2 and 3 hydrophilic; 4 hydrophobic © 2017 Sinauer Associates, Inc. c. 2 hydrophilic; 4 hydrophobic d. 3 hydrophilic; 1 and 4 hydrophobic e. 2 and 3 hydrophilic; 1 and 4 hydrophobic Answer: b Hint: Remember that hydrophilic interactions are those that involve polar bonds. Learning Outcome: 2.2.8.a Distinguish between hydrophilic and hydrophobic interactions using examples. Bloom’s Level: 3. Applying Difficulty Level: Difficult 44. Refer to the figure below. The figure shows a molecule found in biological samples. What interactions will occur if 1 part of this compound is mixed with 20 parts of water, and why? a. Hydrophobic interactions will cause these molecules to disperse evenly between the water molecules. b. Hydrophilic interactions will cause these molecules to disperse evenly between the water molecules. c. Hydrophobic interactions between these molecules and water will cause all of the molecules to form a separate layer. d. Both hydrophobic and hydrophilic interactions between these molecules and water will cause groups of the molecules to form small spherical bunches dispersed in the water. e. Both hydrophobic and hydrophilic interactions between these molecules and water will cause single molecules to disperse evenly between the water molecules. Answer: d Hint: How will the different parts of this molecule interact with water molecules and with other molecules of its kind? Learning Outcome: 2.2.8.a Distinguish between hydrophilic and hydrophobic interactions using examples. Bloom’s Level: 3. Applying Difficulty Level: Difficult 45. The opposite of hydrophobic is a. hydrophilic. b. hygroscopic. c. hydrochloric. d. anisotropic. e. acidophilic. Answer: a Hint: Consider that the root words “hydro” and “phobic” mean “water” and “hating.” What set of root words mean “water” and “loving”? © 2017 Sinauer Associates, Inc. Learning Outcome: 2.2.8.a Distinguish between hydrophilic and hydrophobic interactions using examples. Bloom’s Level: 1. Remembering Difficulty Level: Easy 46. Which statement is false? a. Covalent bonds can be polar or nonpolar depending on whether the atoms in the bond share electrons equally or unequally. b. Hydrogen bonds form between or within molecules. c. Ionic attractions and hydrogen bonds are noncovalent interactions involving differences in charge. d. van der Waals forces are so weak that they have no significant importance in molecular interactions. e. Hydrophobic molecules tend to aggregate together. Answer: d Hint: Remember which types of bonds are fleeting but occur in both polar and nonpolar molecules and can add up to a substantial attractive force. Learning Outcome: 2.2.9.aIdentify instances in which van der Waals forces are important. Bloom’s Level: 2. Understanding Difficulty Level: Difficult 47. Which is an instance of van der Waals forces operating in nature? a. Plants germinating from seeds b. Salt dissolving in water c. Oil separating from water d. Mammalian hearts pumping blood e. Houseflies walking on walls and ceilings Answer: e Hint: Each case represents some action. Which action results from many van der Waals forces operating at once? Learning Outcome: 2.2.9.a Identify instances in which van der Waals forces are important. Bloom’s Level: 3. Applying Difficulty Level: Moderate 48. Which statement about spiders illustrates the importance of van der Waals forces in biology? a. Some spider species live as solitary animals, while others form communal webs. b. On a per-weight basis, spider silk is more resistant to breakage than steel. c. Some spiders paralyze their prey by injecting venom into their bodies. d. Some spider silks are extremely sticky and can adhere to smooth surfaces, such as glass. e. Some spiders secrete digestive juices onto their prey to begin digestion before swallowing it. Answer: d © 2017 Sinauer Associates, Inc. Hint: Think about the properties that a substance would have if it were able to apply a large number of van der Waals forces. Learning Outcome: 2.2.9.a Identify instances in which van der Waals forces are important. Bloom’s Level: 3. Applying Difficulty Level: Difficult 49. Which experimental procedure could be used to provide evidence that living organisms are dynamic systems? a. Analyze the elemental composition of a living plant. b. Follow radioactive carbon atoms in glucose molecules consumed by a mouse. c. Measure water in a fungus by weighing before and after drying the fungus in an oven. d. Compare DNA sequences in bacteria with DNA sequences in yeast. e. Burn plant material in the presence of oxygen and determine the products of combustion. Answer: b Hint: Think about the properties of living things that reveal their constantly changing nature. Learning Outcome: 2.3.1.a Justify the claim that living organisms are dynamic. Bloom’s Level: 3. Applying Difficulty Level: Moderate 50. Which statement provides evidence that living organisms undergo constant change? a. Living organisms contain molecules that can be combusted to form carbon dioxide and water. b. Living organisms contain a large variety of molecules of many different sizes and types. c. Living organisms are composed of cells that function using chemical reactions. d. Living organisms follow the same laws of chemistry and physics that nonliving things follow. e. Living organisms are composed mainly of the elements carbon, hydrogen, oxygen, and nitrogen. Answer: c Hint: What property listed is associated with constant change? Learning Outcome: 2.3.1.a Justify the claim that living organisms are dynamic. Bloom’s Level: 5. Evaluating Difficulty Level: Difficult 51. Consider two scenarios: (1) a living cell metabolizes glucose to carbon dioxide and water, and (2) a pan of water boils on a stove. Which statement correctly compares these scenarios? a. Changes in energy occur as the cell metabolizes glucose, but not as the water boils. b. Atoms are rearranged as the cell metabolizes glucose, but not as the water boils. c. Matter is conserved as the cell metabolizes glucose, but not as the water boils. d. Interactions between molecules change as the cell metabolizes glucose, but not as the water boils. © 2017 Sinauer Associates, Inc. e. Energy is conserved as the cell metabolizes glucose, but not as the water boils. Answer: b Hint: Consider that chemical change is taking place in a cell as it divides, but physical change is taking place in water as it boils. Learning Outcome: 2.3.2.a Describe changes taking place during a chemical reaction. Bloom’s Level: 4. Analyzing Difficulty Level: Moderate 52. Which general chemical principles can be applied to all chemical reactions? a. The number of atoms in the reactants can differ from the number of atoms in the products. b. Matter can neither be created nor destroyed during a chemical reaction. c. Energy cannot change its form during a chemical reaction. d. Some chemical reactions occur without being accompanied by a change in energy. e. Chemical bonds remain unchanged during a chemical reaction. Answer: b Hint: Remember that chemical reactions obey the laws of conservation of energy and conservation of matter. Learning Outcome: 2.3.2.a Describe changes taking place during a chemical reaction. Bloom’s Level: 1. Remembering Difficulty Level: Easy 53. Which statement best explains how atoms change partners when propane combusts? a. Carbon breaks a bond with hydrogen and forms a new bond with hydrogen. b. Carbon breaks a bond with oxygen and forms a bond with hydrogen and oxygen. c. Oxygen breaks a bond with carbon and forms a bond with hydrogen. d. Oxygen breaks a bond with hydrogen and forms a bond with carbon. e. Oxygen breaks a bond with oxygen and forms a bond with carbon or hydrogen. Answer: e Hint: Write out the chemical equation describing the reaction, and use it to think about which bonds are broken and which are formed. Learning Outcome: 2.3.2.a Describe changes taking place during a chemical reaction. Bloom’s Level: 2. Understanding Difficulty Level: Difficult 54. Consider the following statement: In a chemical reaction, the properties of the products are usually similar to the reactants. a. This is true because chemical properties don’t change much when chemical partners change. b. This is true because redox reactions don’t change the properties. c. This is false because the chemical properties can be significantly altered when chemical partners change. d. This is false because a chemical reaction usually changes the mass of the reactants but not their energy. e. This is false because energy can’t be created or destroyed. Answer: c © 2017 Sinauer Associates, Inc. Hint: Consider that chemical reactions cause striking changes. Learning Outcome: 2.3.3.a Compare the products and reactants of a chemical reaction. Bloom’s Level: 1. Remembering Difficulty Level: Moderate 55. The Australian environmental protection agency defines bioremediation as a“process using microorganisms to degrade and detoxify organic substances to harmless compounds, such as carbon dioxide and water, in a confined and controlled environment.” Bioremediation is being used to clean up oil spills, pesticide-contaminated estuaries, contaminated groundwater, and many other cases of pollution. Which statement would be true of bioremediations? a. The products of a bioremediation process have very different properties than the reactants do. b. Bioremediations do not obey the law of conservation of matter. c. The law of conservation of energy does not apply to bioremediations. d. In bioremediations, chemical bonds are conserved as reactants are converted to products. e. Bioremediations involve no change in energy. Answer: a Hint: Consider that bioremediation processes are chemical processes that obey the laws of conservation of energy and matter. Learning Outcome: 2.3.3.a Compare the products and reactants of a chemical reaction. Bloom’s Level: 3. Applying Difficulty Level: Easy 56. Refer to the balanced chemical equation below. C3H8 + 5 O2 4 H2O + 3 CO2 Which statement correctly describes this reaction? a. The products contain the same chemical bonds as the reactants. b. The combined mass of the products differs from the combined mass of the reactants. c. The products contain the same elements in different numbers than the reactants do. d. The products differ from the reactants in their elemental composition. e. The products contain the same number and type of atoms present in the reactants. Answer: e Hint: Remember that products and reactants are not the same but that the laws of conservation of energy and matter must be obeyed whenever reactants are converted to products. Learning Outcome: 2.3.3.a Compare the products and reactants of a chemical reaction. Bloom’s Level: 4. Analyzing Difficulty Level: Moderate 57. Refer to the figure below. © 2017 Sinauer Associates, Inc. A living cell carries out this chemical reaction in many steps with a very small release of heat. The same chemical reaction can be carried out in one step in a chemistry lab using special equipment with the release of a very large amount of heat. Which statement related to this observation is correct? a. Although the overall chemical reactions are the same, the cellular reaction involves less energy release than the reaction carried out in the lab. b. The total amount of energy present before a reaction can change by the end of the reaction, depending on how the reaction proceeds. c. Energy is not conserved in reactions carried out in laboratories; it is only conserved in reactions in living organisms. d. Energy that escapes as heat is not considered when accounting for the changes in energy during any chemical reaction. e. Energy in equals energy out in both cases, but most of the energy released is diverted to chemical bond energy in the cell instead of being released as heat. Answer: e Hint: Consider that the law of conservation of energy applies to all chemical reactions regardless of where they take place. Learning Outcome: 2.3.4.a Explain how the law of conservation of energy applies to chemical reactions. Bloom’s Level: 3. Applying Difficulty Level: Difficult 58. The equation C4H10 + 7 O2  4 CO2 + 6 H2O + energy is incorrect because a. two carbon atoms are missing from the products. b. two hydrogen atoms are missing from the products. c. two carbon atoms are missing from the reactants. d. two hydrogen atoms are missing from the reactants. e. two oxygen atoms are missing from the products. Answer: d Hint: Compare the number of each element on the reactant side to the number of each element on the product side. Learning Outcome: 2.3.4.b Demonstrate an example to show that chemical reactions obey the law of conservation of matter. Bloom’s Level: 3. Applying Difficulty Level: Easy 59. Which set of numbers correctly balances the chemical equation below, describing the combustion of hexane? 2 CXHY + 19 O2 Z CO2 + 14 H2O + energy a. X = 6, Y = 12, Z = 10 b. X = 6, Y = 14, Z = 10 c. X = 6, Y = 14, Z = 12 © 2017 Sinauer Associates, Inc. d. X = 6, Y = 14, Z = 14 e. X = 6, Y = 16, Z = 12 Answer: c Hint: The number of hydrogen atoms is given in the equation and can be used as a starting point for finding the solution. Learning Outcome: 2.3.4.b Demonstrate an example to show that chemical reactions obey the law of conservation of matter. Bloom’s Level: 3. Applying Difficulty Level: Difficult 60. When a chemical reaction occurs, changes in the form of _______ occur, which represents the capacity of the reaction to _______. a. work; release energy b. reactants; absorb energy c. products; do work d. reactants; make products e. energy; do work Answer: e Hint: Remember that energy can be used to perform a useful task. Learning Outcome: 2.3.5.a Explain how energy is involved in a chemical reaction. Bloom’s Level: 2. Understanding Difficulty Level: Moderate 61. Refer to the balanced chemical equation below. 2 H2 + O2 2 H2O + energy When this reaction occurs, energy is released explosively in the form of heat and light. Based on this information and your knowledge of chemical reactions, which statement is correct? a. More energy is stored in two H2 and one O2 than is stored in four O–H bonds. b. The sum of the energy of two H2 and one O2 is equal to the sum of the energy of four O–H bonds. c. A water molecule has more stored energy in its bonds than two H2 and one O2 combined. d. Energy is conserved during this reaction, which means that the chemical bond energies in the products are the same as the chemical bond energies in the reactants. e. Energy is observed during this reaction because all chemical reactions involve a release of energy; some reactions just release more than others. Answer: a Hint: Consider that energy must be put in to break bonds in the reactants and then energy is released when new, different bonds are formed. Learning Outcome: 2.3.5.a Explain how energy is involved in a chemical reaction. Bloom’s Level: 4. Analyzing Difficulty Level: Difficult © 2017 Sinauer Associates, Inc. 62. In an organic chemistry lab, chemical reactions are mainly carried out in organic solvents such as dichloromethane or hexane. Just down the hall in a biochemistry lab, chemical reactions are mainly carried out in aqueous buffers in which water is the solvent. If biochemical reactions involve organic compounds from biological sources, why aren’t biochemical reactions carried out in organic solvents? a. Organic solvents are more hazardous to use than water-based solvents. b. Organic solvents require special disposal not required for water-based solvents. c. Biochemical reactions can be slowed for easier study in aqueous solvents. d. Biochemical reactions normally take place in a water-based solvent. e. Biochemical reactions do not follow the same principles of chemistry that organic reactions follow. Answer: d Hint: Consider that water is the most abundant molecule in a living cell. Learning Outcome: 2.4.1.a Explain why the study of water and its properties is relevant to the study of living organisms. Bloom’s Level: 3. Applying Difficulty Level: Moderate 63. Refer to the figures below. © 2017 Sinauer Associates, Inc. A student is creating a diagram to illustrate the structure of water in an Arctic lake. The student has identified three zones of the lake to label. How should the smaller images be attached to the larger one? a. Ice = A, warm water = C, cold water = B b. Ice = C, warm water = A, cold water = B c. Ice = B, warm water = A, cold water = C d. Ice = C, warm water = B, cold water = A e. Ice = B, warm water = C, cold water = A Answer: b Hint: Which arrangement of water molecules is consistent with the observation that ice floats in liquid water? Learning Outcome: 2.4.2.a Justify the difference in densities of ice and liquid water. Bloom’s Level: 4. Analyzing Difficulty Level: Moderate 64. Refer to the table and three diagrams below. © 2017 Sinauer Associates, Inc. How can the diagrams be used to justify the density measurements of water at the different temperatures given? a. 0.0°C = Z, 4.0°C = Y, 4.4°C = X b. 0.0°C = X, 4.0°C = Y, 4.4°C = Z c. 0.0°C = Y, 4.0°C = Z, 4.4°C = X d. 0.0°C = Z, 4.0°C = X, 4.4°C = Y e. 0.0°C = Y, 4.0°C = X, 4.4°C = Z Answer: b Hint: Estimate the densities of water molecules in the diagrams, rank them from low to high, and then match them to the numerical densities in the table. Learning Outcome: 2.4.2.a Justify the difference in densities of ice and liquid water. Bloom’s Level: 4. Analyzing Difficulty Level: Moderate 65. Although air temperatures at a site on the coast of California can swing widely in very short periods of time, marine animals in the ocean at this site do not experience the same wide temperature swings. Which statement explains this observation? a. Hydrogen bonding between water molecules results in the formation of a rigid latticelike structure in the solid state. b. The density of water changes with temperature as the average distance between water molecules changes. c. A great deal of energy absorbed by water goes into breaking hydrogen bonds between water molecules. d. Water molecules at the surface are hydrogen-bonded to other water molecules below them. e. The polar nature of water molecules makes it an excellent solvent for dissolving polar substances. Answer: c © 2017 Sinauer Associates, Inc. Hint: How do hydrogen bonds between water molecules enable water to absorb so much energy and yet only mildly raise its temperature? Learning Outcome: 2.4.3.a Explain how the structure of water can be used to understand why water temperature changes slowly under the same conditions that cause the temperatures of other substances to change rapidly. Bloom’s Level: 3. Applying Difficulty Level: Moderate 66. Which substance is predicted to have a greater heat capacity per mole than water? a. b. c. d. e. Answer: c Hint: Which structure will have the most types of intermolecular forces of attraction? Learning Outcome: 2.4.3.b Analyze the chemical structures of various compounds including water and predict their relative heat capacities. Bloom’s Level: 4. Analyzing Difficulty Level: Easy 67. Which compound is expected to have a heat capacity per mole most similar to that of water? a. © 2017 Sinauer Associates, Inc. b. c. d. e. Answer: b Hint: Which compound has intermolecular forces of attraction most similar to those of water? Learning Outcome: 2.4.3.b Analyze the chemical structures of various compounds including water and predict their relative heat capacities. Bloom’s Level: 4. Analyzing Difficulty Level: Moderate 68. Refer to the figures below. Rank the compounds in order of lowest to highest heat capacity per mole of compound. a. C < A < B b. A < C < B c. B < A < C © 2017 Sinauer Associates, Inc. d. B < C < A e. C < B P > N > O > H b. P > O > C > N > H c. P > C > N > O > H d. P > C > O > N > H e. P > C > O > H > N Answer: c Learning Outcome: 2.2.2.a Give an example of a covalent bond and show how electrons are involved in formation of the bond. Bloom’s Level: 3. Applying 9. Which interaction between atoms is the strongest? a. Hydrophobic interactions b. Ionic attraction c. Covalent bonds d. van der Waals forces e. Hydrogen bonds Answer: c Learning Outcome: 2.2.3.a Explain why covalent bonds are so strong. Bloom’s Level: 2. Understanding 10. For a covalent bond to be polar, the two atoms that form the bond must have a. differing atomic weights. b. differing numbers of neutrons. c. differing melting points. d. differing electronegativities. e. similar electronegativities. Answer: d Learning Outcome: 2.2.4.a Identify examples of polar covalent and nonpolar covalent bonds. Bloom’s Level: 2. Understanding 11. Polar molecules a. have electric charges that are unequally distributed. b. have the ability to form ions when dissolved in water. c. have electric charges that are equally distributed. d. have bonds with an overall negative charge. e. have bonds with an overall positive charge. Answer: a Learning Outcome: 2.2.5.a Explain why water is a polar molecule. Bloom’s Level: 2. Understanding © 2017 Sinauer Associates, Inc. 12. Hydrocarbons are _______ and _______, whereas salts are _______ and _______. a. nonpolar; hydrophobic; polar; hydrophilic b. nonpolar; hydrophilic; polar; hydrophobic c. nonpolar; hydrophobic, nonpolar, hydrophilic d. polar; hydrophilic; nonpolar; hydrophobic e. polar; hydrophobic; nonpolar; hydrophilic Answer: a Learning Outcome: 2.2.8.a Distinguish between hydrophilic and hydrophobic interactions using examples. Bloom’s Level: 3. Applying 13. Which finding can be used to justify the claim that living organisms are dynamic? a. Microscopic examination of tissue removed from a multicellular organism reveals cells as the underlying basic units of structure. b. Combustion of living plants results in formation of carbon dioxide and water along with a great deal of heat. c. Examination of fossilized remains of dinosaurs indicates that these organisms share some anatomical features with modern birds. d. Elemental analysis of living tissue reveals the presence of many elements in trace quantities. e. Radioisotopic tracing shows that living organisms transform glucose and oxygen to carbon dioxide and water. Answer: e Learning Outcome: 2.3.1.a Justify the claim that living organisms are dynamic. Bloom’s Level: 5. Evaluating 14. Which statement about chemical reactions is false? a. They occur when atoms combine or change their bonding partners. b. They may lead to the creation or destruction of energy. c. They may go to completion. d. They may lead to changes in forms of energy. e. They convert reactants into products. Answer: b Learning Outcome: 2.3.2.a Describe changes taking place during a chemical reaction. Bloom’s Level: 2. Understanding 15. Which equation represents a chemical reaction that obeys the law of conservation of matter? a. C6H12O6 + O2 CO2 + H2O b. C6H12O6 + 8 O2 6 CO2 + 8 H2O c. C6H12O6 + 12 O2 3 CO2 + 8 H2O d. C6H12O6 + 6 O2 6 CO2 + 6 H2O e. 2 C6H12O6 + 6 O2 12 CO2 + 6 H2O Answer: d © 2017 Sinauer Associates, Inc. Learning Outcome: 2.3.4.b Demonstrate an example to show that chemical reactions obey the law of conservation of matter. Bloom’s Level: 4. Analyzing 16. Of the statements below, which best explains why the study of water is relevant to the study of living organisms? a. Water is produced when amino acids polymerize to form proteins and when nucleotides polymerize to form RNA and DNA. b. Ninety-six percent of water on Earth is found in the oceans, 1 percent is found in bays and estuaries, and 3 percent is found in freshwater locations. c. An average rainstorm drops about 100,000 liters of water over 1 acre of land. d. Sixty percent of an adult human’s body weight is due to water, with two-thirds of this water located inside cells and one-third outside cells. e. Water is the only compound on Earth that can be found as a gas, a liquid, and a solid in different natural settings. Answer: d Learning Outcome: 2.4.1.a Explain why the study of water and its properties is relevant to the study of living organisms. Bloom’s Level: 5. Evaluating 17. Which property of water contributes most to the ability of fish in lakes to survive very cold winters? a. Strong cohesive forces b. High heat capacity c. Density differences at different temperatures d. High surface tension e. High heat of vaporization Answer: c Learning Outcome: 2.4.2.a Justify the difference in densities of ice and liquid water. Bloom’s Level: 3. Applying 18. Sweating is a useful cooling device for humans because water a. absorbs a great deal of heat in changing from its liquid state to its gaseous state. b. absorbs a great deal of heat in changing from its solid state to its liquid state. c. can exist in three states at temperatures common on Earth. d. is an outstanding solvent. e. ionizes readily. Answer: a Learning Outcome: 2.4.4.b Describe how water’s heat of vaporization affects living organisms. Bloom’s Level:3. Applying 19. Given that Avogadro’s number is 6.02 × 1023, how many molecules of KCl are there in 10–13 liter of a 1 MKCl solution? a. 6.02 × 1036 b. 6.02 × 1010 © 2017 Sinauer Associates, Inc. c. 6.02 × 10–10 d. 6.02 × 103 e. 6.02 × 1013 Answer: b Learning Outcome: 2.4.7.a Perform quantitative analyses of biochemical compounds using the mole concept. Bloom’s Level: 4. Analyzing 20. Why is the pH of a 0.1 M solution of acetic acid in water higher than that of a 0.1 M solution of HCl in water? a. HCl is a weaker acid than acetic acid. b. The acetic acid does not fully ionize in water, whereas HCl does. c. HCl does not fully ionize in water, whereas acetic acid does. d. Acetic acid is a better buffer than HCl. e. Acetate (ionized acetic acid) is a strong base. Answer: b Learning Outcome: 2.4.8.a Predict and explain changes in pH caused by changes in concentration of weak acids or bases in living tissue. Bloom’s Level: 3. Applying © 2017 Sinauer Associates, Inc.