Summary Test Bank for Campbell Biology, 12th Edition by Urry, Cain, Wasserman, Minorsky & Orr (Chapters 1–56) | 2026 Updated Comprehensive Biology Exam Questions

1 Copyright © 2011 Pearson Education, Inc. Campbell's Biology, 12e Chapter 1: Evolution, the Themes of Biology, and Scientific Inquiry This introductory chapter explores the basic themes and concepts of biology, with emphasis on the core theme of evolution. It also introduces students to the thinking of scientists. Questions are therefore general; however, an effort has been made to include some from each skill level. As in the rest of this test bank, questions that feature art or those for which several questions follow upon some data or a scenario are placed together at the end of the chapter. Multiple-Choice Questions 1) A localized group of organisms that belong to the same species is called a A) biosystem. B) community. C) population. D) ecosystem. E) family. Answer: C Topic: Concept 1.1 Skill: Knowledge/Comprehension 2) Organisms interact with their environments, exchanging matter and energy. For example, plant chloroplasts convert the energy of sunlight into A) the energy of motion. B) carbon dioxide and water. C) the potential energy of chemical bonds. D) oxygen. E) kinetic energy. Answer: C Topic: Concept 1.1 Skill: Knowledge/Comprehension 3) The main source of energy for producers in an ecosystem is A) light energy. B) kinetic energy. C) thermal energy. D) chemical energy. E) ATP. Answer: A Topic: Concept 1.1 Skill: Knowledge/Comprehension 2 Copyright © 2011 Pearson Education, Inc. 4) Which of the following types of cells utilize deoxyribonucleic acid (DNA) as their genetic material but do not have their DNA encased within a nuclear envelope? A) animal B) plant C) archaea D) fungi E) protists Answer: C Topic: Concept 1.1 Skill: Application/Analysis 5) To understand the chemical basis of inheritance, we must understand the molecular structure of DNA. This is an example of the application of which concept to the study of biology? A) evolution B) emergent properties C) reductionism D) the cell theory E) feedback regulation Answer: C Topic: Concept 1.1 Skill: Application/Analysis 6) Once labor begins in childbirth, contractions increase in intensity and frequency until delivery. The increasing labor contractions of childbirth are an example of which type of regulation? A) a bioinformatic system B) positive feedback C) negative feedback D) feedback inhibition E) enzymatic catalysis Answer: B Topic: Concept 1.1 Skill: Application/Analysis 7) When the body's blood glucose level rises, the pancreas secretes insulin and, as a result, the blood glucose level declines. When the blood glucose level is low, the pancreas secretes glucagon and, as a result, the blood glucose level rises. Such regulation of the blood glucose level is the result of A) catalytic feedback. B) positive feedback. C) negative feedback. D) bioinformatic regulation. E) protein-protein interactions. Answer: C Topic: Concept 1.1 Skill: Application/Analysis 3 Copyright © 2011 Pearson Education, Inc. 8) Which branch of biology is concerned with the naming and classifying of organisms? A) informatics B) schematic biology C) taxonomy D) genomics E) evolution Answer: C Topic: Concept 1.1 Skill: Knowledge/Comprehension 9) Prokaryotic and eukaryotic cells generally have which of the following features in common? A) a membrane-bounded nucleus B) a cell wall made of cellulose C) ribosomes D) flagella or cilia that contain microtubules E) linear chromosomes made of DNA and protein Answer: C Topic: Concept 1.1 Skill: Knowledge/Comprehension 10) Prokaryotes are classified as belonging to two different domains. What are the domains? A) Bacteria and Eukarya B) Archaea and Monera C) Eukarya and Monera D) Bacteria and Protista E) Bacteria and Archaea Answer: E Topic: Concept 1.1 Skill: Knowledge/Comprehension 11) Global warming, as demonstrated by observations such as melting of glaciers, increasing CO2 levels, and increasing average ambient temperatures, has already had many effects on living organisms. Which of the following might best offer a solution to this problem? A) Continue to measure these and other parameters of the problem. B) Increase the abilities of animals to migrate to more suitable habitats. C) Do nothing; nature will attain its own balance. D) Limit the burning of fossil fuels and regulate our loss of forested areas. E) Recycle as much as possible. Answer: D Topic: Concept 1.1 Skill: Synthesis/Evaluation 4 Copyright © 2011 Pearson Education, Inc. 12) A water sample from a hot thermal vent contained a single-celled organism that had a cell wall but lacked a nucleus. What is its most likely classification? A) Eukarya B) Archaea C) Animalia D) Protista E) Fungi Answer: B Topic: Concept 1.2 Skill: Application/Analysis 13) A filamentous organism has been isolated from decomposing organic matter. This organism has a cell wall but no chloroplasts. How would you classify this organism? A) domain Bacteria, kingdom Prokaryota B) domain Archaea, kingdom Bacteria C) domain Eukarya, kingdom Plantae D) domain Eukarya, kingdom Protista E) domain Eukarya, kingdom Fungi Answer: E Topic: Concept 1.2 Skill: Application/Analysis 14) Which of these provides evidence of the common ancestry of all life? A) ubiquitous use of catalysts by living systems B) near universality of the genetic code C) structure of the nucleus D) structure of cilia E) structure of chloroplasts Answer: B Topic: Concept 1.2 Skill: Application/Analysis 15) Which of the following is (are) true of natural selection? A) It requires genetic variation. B) It results in descent with modification. C) It involves differential reproductive success. D) It results in descent with modification and involves differential reproductive success. E) It requires genetic variation, results in descent with modification, and involves differential reproductive success. Answer: E Topic: Concept 1.2 Skill: Knowledge/Comprehension 5 Copyright © 2011 Pearson Education, Inc. 16) Charles Darwin proposed a mechanism for descent with modification that stated that organisms of a particular species are adapted to their environment when they possess A) non-inheritable traits that enhance their survival in the local environment. B) non-inheritable traits that enhance their reproductive success in the local environment. C) non-inheritable traits that enhance their survival and reproductive success in the local environment. D) inheritable traits that enhance their survival and reproductive success in the local environment. E) inheritable traits that decrease their survival and reproductive success in the local environment. Answer: D Topic: Concept 1.2 Skill: Knowledge/Comprehension 17) Which of these individuals is likely to be most successful in an evolutionary sense? A) a reproductively sterile individual who never falls ill B) an organism that dies after five days of life but leaves 10 offspring, all of whom survive to reproduce C) a male who mates with 20 females and fathers one offspring D) an organism that lives 100 years and leaves two offspring, both of whom survive to reproduce E) a female who mates with 20 males and produces one offspring that lives to reproduce Answer: B Topic: Concept 1.2 Skill: Application/Analysis 18) In a hypothetical world, every 50 years people over 6 feet tall are eliminated from the population before they reproduce. Based on your knowledge of natural selection, you would predict that the average height of the human population will A) remain unchanged. B) gradually decline. C) rapidly decline. D) gradually increase. E) rapidly increase. Answer: B Topic: Concept 1.2 Skill: Application/Analysis 19) Through time, the lineage that led to modern whales shows a change from four-limbed land animals to aquatic animals with two limbs that function as flippers. This change is best explained by A) natural philosophy. B) creationism. C) the hierarchy of the biological organization of life. D) natural selection. E) feedback inhibition. Answer: D Topic: Concept 1.2 Skill: Application/Analysis 6 Copyright © 2011 Pearson Education, Inc. 20) What is the major difference between a kingdom and a domain? A) A kingdom can include several subgroups known as domains. B) All eukarya belong to one domain. C) All prokaryotes belong to one domain. D) The importance of fungi has led scientists to make them the whole of one domain. E) Only organisms that produce their own food belong to one of the domains. Answer: B Topic: Concept 1.2 Skill: Knowledge/Comprehension 21) Which of the following best describes what occurred after the publication of Charles Darwin's On the Origin of Species? A) The book received little attention except from a small scientific community. B) The book was banned from schools. C) The book was widely discussed and disseminated. D) The book's authorship was disputed. E) The book was discredited by most scientists. Answer: C Topic: Concept 1.2 Skill: Knowledge/Comprehension 22) Why is Darwin considered original in his thinking? A) He provided examples of organisms that had evolved over time. B) He demonstrated that evolution is continuing to occur now. C) He described the relationship between genes and evolution. D) He proposed the mechanism that explained how evolution takes place. E) He observed that organisms produce large numbers of offspring. Answer: D Topic: Concept 1.2 Skill: Knowledge/Comprehension 23) Darwin's finches, collected from the Galápagos Islands, illustrate which of the following? A) mutation frequency B) ancestors from different regions C) adaptive radiation D) vestigial anatomic structures E) the accuracy of the fossil record Answer: C Topic: Concept 1.2 Skill: Knowledge/Comprehension 24) Which of the following categories of organisms is least likely to be revised? A) kingdom B) class C) order D) phylum E) species Answer: E Topic: Concept 1.2 Skill: Synthesis/Evaluation 7 Copyright © 2011 Pearson Education, Inc. 25) What is the major distinguishing characteristic of fungi? A) gaining nutrition through ingestion B) being sedentary C) being prokaryotic D) absorbing dissolved nutrients E) being decomposers of dead organisms Answer: D Topic: Concept 1.2 Skill: Knowledge/Comprehension 26) What are archaea? A) Prokaryotes characterized as extremophiles that share some bacterial and some eukaryotic traits. B) Organisms that are adapted to high temperature environments, such as in volcanic springs. C) Single-celled organisms that are killed by the application of antibiotics at certain concentrations. D) Bacteria-like organisms that can live only in extreme salt environments. E) Primitive protist-like creatures possessing fewer than two chromosomes per cell. Answer: A Topic: Concept 1.2 Skill: Knowledge/Comprehension 27) According to Darwinian theory, which of the following exhibits the greatest fitness for evolutionary success? A) the species with the longest life B) the individuals within a population that have the greatest reproductive success C) the phylum with members that occupy the greatest number of habitats D) the community of organisms that is capable of living in the most nutrient-poor biome E) the organism that produces its own nutrients most efficiently Answer: B Topic: Concept 1.2 Skill: Knowledge/Comprehension 28) Similarities and differences among/between life-forms over time are most efficiently recorded by scientists in which field(s) of study? A) paleontology B) paleontology and anatomy C) paleontology, anatomy, and taxonomy D) paleontology, anatomy, taxonomy, and genetics E) paleontology, anatomy, taxonomy, genetics, and ecology Answer: E Topic: Concept 1.2 Skill: Synthesis/Evaluation 8 Copyright © 2011 Pearson Education, Inc. 29) Why is the theme of evolution considered to be the core theme of biology by biologists? A) It provides a framework within which all biological investigation makes sense. B) It is recognized as the core theme of biology by organizations such as the National Science Foundation. C) Controversy about this theory provides a basis for a great deal of experimental research. D) Since it cannot be proven, biologists will be able to study evolutionary possibilities for many years. E) Biologists do not subscribe to alternative models. Answer: A Topic: Concept 1.2 Skill: Synthesis/Evaluation 30) The method of scientific inquiry that describes natural structures and processes as accurately as possible through careful observation and the analysis of data is known as A) hypothesis-based science. B) discovery science. C) experimental science. D) quantitative science. E) qualitative science. Answer: B Topic: Concept 1.3 Skill: Knowledge/Comprehension 31) Collecting data based on observation is an example of ; analyzing this data to reach a conclusion is an example of reasoning. A) hypothesis-based science; inductive B) the process of science; deductive C) discovery science; inductive D) descriptive science; deductive E) hypothesis-based science; deductive Answer: C Topic: Concept 1.3 Skill: Application/Analysis 32) When applying the process of science, which of these is tested? A) a question B) a result C) an observation D) a prediction E) a hypothesis Answer: D Topic: Concept 1.3 Skill: Knowledge/Comprehension 9 Copyright © 2011 Pearson Education, Inc. 33) A controlled experiment is one in which A) the experiment is repeated many times to ensure that the results are accurate. B) the experiment proceeds at a slow pace to guarantee that the scientist can carefully observe all reactions and process all experimental data. C) there are at least two groups, one of which does not receive the experimental treatment. D) there are at least two groups, one differing from the other by two or more variables. E) there is one group for which the scientist controls all variables. Answer: C Topic: Concept 1.3 Skill: Application/Analysis 34) Why is it important that an experiment include a control group? A) The control group is the group that the researcher is in control of, the group in which the researcher predetermines the results. B) The control group provides a reserve of experimental subjects. C) A control group is required for the development of an "If…then" statement. D) A control group assures that an experiment will be repeatable. E) Without a control group, there is no basis for knowing if a particular result is due to the variable being tested. Answer: E Topic: Concept 1.3 Skill: Application/Analysis 35) The application of scientific knowledge for some specific purpose is known as A) technology. B) deductive science. C) inductive science. D) anthropologic science. E) pure science. Answer: A Topic: Concept 1.3 Skill: Knowledge/Comprehension 36) Which of the following are qualities of any good scientific hypothesis? I. It is testable. II. It is falsifiable. III. It produces quantitative data. IV. It produces results that can be replicated. A) I only B) II only C) III only D) I and II E) III and IV Answer: D Topic: Concept 1.3 Skill: Knowledge/Comprehension 10 Copyright © 2011 Pearson Education, Inc. 37) When a hypothesis cannot be written in an "If…then" format, what does this mean? A) It does not represent deductive reasoning. B) It cannot be a scientific hypothesis. C) The subject cannot be explored scientifically. D) The hypothesizer does not have sufficient information. E) It cannot be testable. Answer: A Topic: Concept 1.3 Skill: Knowledge/Comprehension 38) In presenting data that result from an experiment, a group of students show that most of their measurements fall on a straight diagonal line on their graph. However, two of their data points are "outliers" and fall far to one side of the expected relationship. What should they do? A) Do not show these points but write a footnote that the graph represents the correct data. B) Average several trials and therefore rule out the improbable results. C) Show all results obtained and then try to explore the reason(s) for these outliers. D) Throw out this set of data and try again. E) Change the details of the experiment until they can obtain the expected results. Answer: C Topic: Concept 1.3 Skill: Synthesis/Evaluation 39) Which of the following is the best description of a control for an experiment? A) The control group is kept in an unchanging environment. B) The control is left alone by the experimenters. C) The control group is matched with the experimental group except for the one experimental variable. D) The control group is exposed to only one variable rather than several. E) Only the experimental group is tested or measured. Answer: C Topic: Concept 1.3 Skill: Knowledge/Comprehension 40) Given the cooperativity of science, which of the following is most likely to result in an investigator being intellectually looked down upon by other scientists? A) Making money as the result of studies in which a new medication is discovered. B) Doing meticulous experiments that show data that contradict what has been previously reported by the scientific community. C) Spending most of a lifetime investigating a small and seemingly unimportant organism. D) Getting negative results from the same set of experiments. E) Being found to have falsified or created data to better fit a hypothesis. Answer: E Topic: Concept 1.3 Skill: Synthesis/Evaluation 11 Copyright © 2011 Pearson Education, Inc. 41) Which of these is an example of inductive reasoning? A) Hundreds of individuals of a species have been observed and all are photosynthetic; therefore, the species is photosynthetic. B) These organisms live in sunny parts of this area so they are able to photosynthesize. C) If horses are always found grazing on grass, they can be only herbivores and not omnivores. D) If protists are all single-celled, then they are incapable of aggregating. E) If two species are members of the same genus, they are more alike than each of them could be to a different genus. Answer: A Topic: Concept 1.3 Skill: Knowledge/Comprehension 42) In a high school laboratory, which of the following constitutes an experiment? I. learning to use a microscope by examining fixed specimens on slides II. being able to examine swimming protists under a microscope III. extracting pigments from plant leaves and separating the types of pigments for identification IV. preparing root tips for examination by staining them A) I only B) II only C) III only D) II and III only E) II, III, and IV Answer: C Topic: Concept 1.3 Skill: Knowledge/Comprehension 43) Which of the following best describes a model organism? A) It is often pictured in textbooks and easy for students to imagine. B) It lends itself to many studies that are useful to beginning students. C) It is well studied, easy to grow, and results are widely applicable. D) It is small, inexpensive to raise, and lives a long time. E) It has been chosen for study by the earliest biologists. Answer: C Topic: Concept 1.4 Skill: Knowledge/Comprehension 44) Why is a scientific topic best discussed by people of varying points of view, a variety of subdisciplines, and diverse cultures? A) They can rectify each other's approach to make it truly scientific. B) Robust and critical discussion between diverse groups improves scientific thinking. C) Scientists can explain to others that they need to work in isolation to utilize the scientific method more productively. D) This is another way of making science more reproducible. E) Scientists need to exchange their ideas with other disciplines and cultures so that all groups are in consensus with the course of future research. Answer: B Topic: Concept 1.4 Skill: Synthesis/Evaluation 12 Copyright © 2011 Pearson Education, Inc. Art Questions 45) The illustration above most probably represents A) a computer simulation of the structure of a eukaryotic cell. B) a map of a network of protein interactions within a eukaryotic cell. C) an inventory of all the genes in a fruit fly. D) an X-ray diffraction image of the nucleus and cytoplasm of a eukaryotic cell. E) a computer-generated map of the interaction of genes and cytoplasm in a prokaryotic cell. Answer: B Topic: Concept 1.1 Skill: Knowledge/Comprehension 13 Copyright © 2011 Pearson Education, Inc. 46) What do these two plants have in common? A) adaptations to extreme heat B) adaptations to conserve water C) identical stem structures D) identical flower structures E) lack of photosynthesis Answer: B Topic: Concept 1.1 Skill: Synthesis/Evaluation 14 Copyright © 2011 Pearson Education, Inc. Use the following information to answer the questions below. Golden algae are a group of protists whose color is due to carotenoid pigments: yellow and brown. Most have two flagella and all are photosynthetic. A group of students was given a significant sample of one of these (Dinobryon) that is colonial. Their instructions for the project were to design two or more experiments that could be done with these organisms. 47) Since these organisms are protists, which of these characteristics could the students assume to be true? A) The organisms are photosynthetic. B) All of them are marine. C) They are single-celled. D) They lack membrane-bound organelles. E) Each has a single circular molecule of DNA. Answer: A Topic: Concept 1.3 Skill: Knowledge/Comprehension 48) The students decide that for one of their experiments, they want to see whether the organisms can photosynthesize. Which of the following is the best hypothesis? A) If the Dinobryon can live 5 days without added food, they must be able to photosynthesize. B) If the Dinobryon can live without exposure to light for 5 days, they must be able to photosynthesize. C) If the Dinobryon photosynthesize, they must need no other minerals or nutrients and will be able to live in distilled water and light alone. D) If the Dinobryon are kept in the dark, one-half will be expected to die in 5 days. E) If the Dinobryon are able to photosynthesize, the students should be able to extract photosynthetic pigments. Answer: E Topic: Concept 1.3 Skill: Application/Analysis 15 Copyright © 2011 Pearson Education, Inc. 49) For their second experiment, the students want to know whether the Dinobryon have to live in colonies or can be free living. How might they proceed? A) Observe each day to see whether new organisms are ever reproduced as single cells. B) Observe whether only specialized cells are able to divide to produce new colonies. C) Divide a sample into single cells and measure the length of time they remain this way. D) Divide a sample into single cells and observe them. E) Divide a sample into single cells and see whether they come back together. Answer: C Topic: Concept 1.3 Skill: Application/Analysis 50) The students plan to gather data from the project. Which of the following would be the best way to present what they gather from experimental groups as opposed to controls? A) qualitatively, noting color, size, and so on B) measuring the number of new colonies formed during every 12-hour period C) counting the number of new colonies after a week D) measuring the size of each new colony in millimeters (mm) of length E) measuring the dry weight of all new colonies in grams Answer: B Topic: Concept 1.3 Skill: Synthesis/Evaluation Scenario Questions The following is a list of biology themes discussed in Chapter 1. Use them to answer the following questions. I. New properties emerge at each level in the biological hierarchy. II. Organisms interact with other organisms and the physical environment. III. Life requires energy transfer and transformation. IV. Structure and function are correlated at all levels of biological organization. V. Cells are an organism's basic units of structure and function. VI. The continuity of life is based on heritable information in the form of DNA. VII. Feedback mechanisms regulate biological systems. VIII. Evolution accounts for the unity and diversity of life. 51) Which theme(s) is/are best illustrated by an experiment in which a biologist seeks a medication that will inhibit pain responses in a cancer patient? A) II B) VII C) III and V D) V and VIII E) VI and VII Answer: B Topic: Concept 1.1 Skill: Application/Analysis 16 Copyright © 2011 Pearson Education, Inc. 52) Which theme(s) is/are best illustrated by a group of investigators who are trying to classify and explain the ecology of an area known as the Big Thicket? A) I only B) II only C) VIII only D) IV and VI E) I and II Answer: E Topic: Concept 1.1 Skill: Application/Analysis 53) Which theme(s) is/are illustrated when a group of students is trying to establish which phase of cell division in root tips happens most quickly? A) IV only B) V only C) VII only D) IV, V, and VI E) V, VI, and VII Answer: D Topic: Concept 1.1 Skill: Application/Analysis 54) Which theme(s) is/are illustrated when a biology class is comparing the rates of photosynthesis between leaves of a flowering plant species (Gerbera jamesonii) and a species of fern (Polypodium polypodioides)? A) I only B) II only C) I and III D) I and VII E) I, III, and V Answer: E Topic: Concept 1.1 Skill: Application/Analysis End-of-Chapter Questions The following questions are from the end-of-chapter “Test Your Understanding” section in Chapter 1 of the textbook. 55) All the organisms on your campus make up A) an ecosystem. B) a community. C) a population. D) an experimental group. E) a taxonomic domain. Answer: B Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 17 Copyright © 2011 Pearson Education, Inc. 56) Which of the following is a correct sequence of levels in life's hierarchy, proceeding downward from an individual animal? A) brain, organ system, nerve cell, nervous tissue B) organ system, nervous tissue, brain C) organism, organ system, tissue, cell, organ D) nervous system, brain, nervous tissue, nerve cell E) organ system, tissue, molecule, cell Answer: D Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 57) Which of the following is not an observation or inference on which Darwin's theory of natural selection is based? A) Poorly adapted individuals never produce offspring. B) There is heritable variation among individuals. C) Because of overproduction of offspring, there is competition for limited resources. D) Individuals whose inherited characteristics best fit them to the environment will generally produce more offspring. E) A population can become adapted to its environment over time. Answer: A Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 58) Systems biology is mainly an attempt to A) analyze genomes from different species. B) simplify complex problems by reducing the system into smaller, less complex units. C) understand the behavior of entire biological systems. D) build high-throughput machines for the rapid acquisition of biological data. E) speed up the technological application of scientific knowledge. Answer: C Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 59) Protists and bacteria are grouped into different domains because A) protists eat bacteria. B) bacteria are not made of cells. C) protists have a membrane-bounded nucleus, which bacterial cells lack. D) bacteria decompose protists. E) protists are photosynthetic. Answer: C Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 18 Copyright © 2011 Pearson Education, Inc. 60) Which of the following best demonstrates the unity among all organisms? A) matching DNA nucleotide sequences B) descent with modification C) the structure and function of DNA D) natural selection E) emergent properties Answer: C Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 61) A controlled experiment is one that A) proceeds slowly enough that a scientist can make careful records of the results. B) tests experimental and control groups in parallel. C) is repeated many times to make sure the results are accurate. D) keeps all variables constant. E) is supervised by an experienced scientist. Answer: B Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 62) Which of the following statements best distinguishes hypotheses from theories in science? A) Theories are hypotheses that have been proved. B) Hypotheses are guesses; theories are correct answers. C) Hypotheses usually are relatively narrow in scope; theories have broad explanatory power. D) Hypotheses and theories are essentially the same thing. E) Theories are proved true; hypotheses are often falsified. Answer: C Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 63) Which of the following is an example of qualitative data? A) The temperature decreased from 20°C to 15°C. B) The plant's height is 25 centimeters (cm). C) The fish swam in a zigzag motion. D) The six pairs of robins hatched an average of three chicks. E) The contents of the stomach are mixed every 20 seconds. Answer: C Topic: End-of-Chapter Questions Skill: Application/Analysis 64) Which of the following best describes the logic of scientific inquiry? A) If I generate a testable hypothesis, tests and observations will support it. B) If my prediction is correct, it will lead to a testable hypothesis. C) If my observations are accurate, they will support my hypothesis. D) If my hypothesis is correct, I can expect certain test results. E) If my experiments are set up right, they will lead to a testable hypothesis. Answer: D Topic: End-of-Chapter Questions Skill: Application/Analysis 1 Copyright © 2011 Pearson Education, Inc. Campbell's Biology, 12e Chapter 2 The Chemical Context of Life This chapter presents basic chemical principles for understanding the chemical context of living organisms, from atomic structure to the nature of chemical bonds and an introduction to chemical equilibrium. These questions focus on elements most important to life or the study of life, including the elements that comprise organic molecules and important trace elements. Some isotopes are important in geologic dating and in biological tracer studies. How elements participate in forming different types of chemical bonds is essential to mastering subsequent topics on the behavior and properties of biological molecules, structures, and energy metabolism. Multiple-Choice Questions 1) About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter? A) carbon, sodium, hydrogen, nitrogen B) carbon, oxygen, phosphorus, hydrogen C) oxygen, hydrogen, calcium, nitrogen D) carbon, hydrogen, nitrogen, oxygen E) carbon, oxygen, nitrogen, calcium Answer: D Topic: Concept 2.1 Skill: Knowledge/Comprehension 2) Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants? A) nitrogen B) calcium C) iodine D) sodium E) phosphorus Answer: C Topic: Concept 2.1 Skill: Knowledge/Comprehension 3) Which of the following statements is false? A) Carbon, hydrogen, oxygen, and nitrogen are the most abundant elements of living matter. B) Some trace elements are very abundant on Earth. C) Virtually all organisms require the same elements in the same quantities. D) Iron is an example of an element needed by all organisms. E) Other than some trace elements, animals are mostly made up of the same elements as plants, in similar proportions. Answer: C Topic: Concept 2.1 Skill: Application/Analysis 2 Copyright © 2011 Pearson Education, Inc. 4) What factors are most important in determining which elements are most common in living matter? A) the relative abundances of the elements in Earth's crust and atmosphere B) the emergent properties of the simple compounds made from these elements C) the reactivity of the elements with water D) the chemical stability of the elements E) both the relative abundances of the elements and the emergent properties of the compounds made from these elements Answer: E Topic: Concept 2.1 Skill: Synthesis/Evaluation 5) Why is each element unique and different from other elements in chemical properties? A) Each element has a unique atomic mass. B) Each element has a unique atomic weight. C) Each element has a unique number of protons in its nucleus. D) Each element has a unique number of neutrons in its nucleus. E) Each element has different radioactive properties. Answer: C Topic: Concept 2.2 Skill: Knowledge/Comprehension 6) Knowing just the atomic mass of an element allows inferences about which of the following? A) the chemical properties of the element B) the number of protons in the element C) the number of neutrons in the element D) the number of protons plus neutrons in the element E) both the number of protons and the chemical properties of the element Answer: D Topic: Concept 2.2 Skill: Application/Analysis 7) In what way are elements in the same column of the periodic table the same? A) They have the same number of protons. B) They have the same number of neutrons. C) They have the same number of electrons. D) They have the same number of electrons in their valence shell. E) They have the same number of electron shells. Answer: D Topic: Concept 2.2 Skill: Knowledge/Comprehension 3 Copyright © 2011 Pearson Education, Inc. 8) Oxygen has an atomic number of 8 and a mass number of 16. Thus, what is the atomic mass of an oxygen atom? A) exactly 8 grams B) exactly 8 daltons C) approximately 16 grams D) approximately 16 daltons E) 24 amu (atomic mass units) Answer: D Topic: Concept 2.2 Skill: Knowledge/Comprehension 9) The nucleus of a nitrogen atom contains 7 neutrons and 7 protons. Which of the following is a correct statement concerning nitrogen? A) The nitrogen atom has a mass number of approximately 7 daltons and an atomic mass of 14. B) The nitrogen atom has a mass number of approximately 14 daltons and an atomic mass of 7. C) The nitrogen atom has a mass number of 14 and an atomic mass of 7 grams. D) The nitrogen atom has a mass number of 7 and an atomic number of 14. E) The nitrogen atom has a mass number of 14 and an atomic mass of approximately 14 daltons. Answer: E Topic: Concept 2.2 Skill: Knowledge/Comprehension 10) Molybdenum has an atomic number of 42. Several common isotopes exist, with mass numbers of 92, 94, 95, 96, 97, 98, and 100. Therefore, which of the following can be true? A) Molybdenum atoms can have between 50 and 58 neutrons. B) The isotopes of molybdenum have different electron configurations. C) The isotopes of molybdenum can have between 50 and 58 protons. D) The isotopes of molybdenum have between 50 and 58 neutrons and have different electron configurations. E) The isotopes of molybdenum have between 50 and 58 protons and have different electron configurations. Answer: A Topic: Concept 2.2 Skill: Knowledge/Comprehension 11) Carbon-12 is the most common isotope of carbon, and has an atomic mass of 12 daltons. A mole of carbon in naturally occurring coal, however, weighs slightly more than 12 grams. Why? A) The atomic mass does not include the mass of electrons. B) Some carbon atoms in nature have an extra proton. C) Some carbon atoms in nature have more neutrons. D) Some carbon atoms in nature have a different valence electron distribution. E) Some carbon atoms in nature have undergone radioactive decay. Answer: C Topic: Concept 2.2 Skill: Application/Analysis 4 Copyright © 2011 Pearson Education, Inc. 12) Which of the following best describes the relationship between the atoms described below? Atom 1 Atom 2 H H A) They are isomers. B) They are polymers. C) They are isotopes. D) They contain 1 and 3 protons, respectively. E) They each contain 1 neutron. Answer: C Topic: Concept 2.2 Skill: Knowledge/Comprehension 13) The precise weight of a mole of some pure elements like silicon (Si) can vary slightly from the standard atomic mass, or even from sample to sample. Why? A) The element may undergo radioactive decay. B) The element may react with itself and gain or lose subatomic particles. C) The atoms of the element form chemical bonds with each other, and that changes the weight of the element. D) The element may have multiple stable isotopes, and the isotopic composition may vary from sample to sample. E) The amount of energy absorbed by the element affects the mass of its electrons, and thus the atomic mass can vary slightly. Answer: D Topic: Concept 2.2 Skill: Application/Analysis 14) One difference between carbon-12 ( 12C) is that carbon-14 ( 14C) has 6 6 A) two more protons than carbon-12. B) two more electrons than carbon-12. C) two more neutrons than carbon-12. D) two more protons and two more neutrons than carbon-12. E) two more electrons and two more neutrons than carbon-12. Answer: C Topic: Concept 2.2 Skill: Knowledge/Comprehension 15) An atom has 6 electrons in its outer shell. How many unpaired electrons does it have? A) 0 B) 2 C) 4 D) 6 E) 2 or 4 Answer: B Topic: Concept 2.2 Skill: Knowledge/Comprehension 5 Copyright © 2011 Pearson Education, Inc. 16) The atomic number of nitrogen is 7. Nitrogen-15 is heavier than nitrogen-14 because the atomic nucleus of nitrogen-15 contains how many neutrons? A) 6 B) 7 C) 8 D) 12 E) 14 Answer: C Topic: Concept 2.2 Skill: Knowledge/Comprehension 17) Electrons exist only at fixed levels of potential energy. However, if an atom absorbs sufficient energy, a possible result is that A) an electron may move to an electron shell farther away from the nucleus. B) an electron may move to an electron shell closer to the nucleus. C) the atom may become a radioactive isotope. D) the atom would become a positively charged ion, or cation, and become a radioactive isotope. E) the atom would become a negatively charged ion, or anion. Answer: A Topic: Concept 2.2 Skill: Knowledge/Comprehension 18) The atomic number of neon is 10. Therefore, which of the following is most correct about an atom of neon? A) It has 8 electrons in its outer electron shell. B) It is inert. C) It has an atomic mass of 10 daltons. D) It has 8 electrons in its outer electron shell and it is inert. E) It has 8 electrons in its outer electron shell, it is inert, and it has an atomic mass of 10 daltons. Answer: D Topic: Concept 2.2 Skill: Knowledge/Comprehension 19) From its atomic number of 15, it is possible to predict that the phosphorus atom has A) 15 neutrons. B) 15 protons. C) 15 electrons. D) 8 electrons in its outermost electron shell. E) 15 protons and 15 electrons. Answer: E Topic: Concept 2.2 Skill: Knowledge/Comprehension 6 Copyright © 2011 Pearson Education, Inc. 6 20) Atoms whose outer electron shells contain 8 electrons tend to A) form ions in aqueous solutions. B) form hydrogen bonds in aqueous solutions. C) be stable and chemically nonreactive, or inert. D) be gaseous at room temperature. E) be both chemically inert and gaseous at room temperature. Answer: E Topic: Concept 2.2 Skill: Knowledge/Comprehension 21) The atomic number of each atom is given to the left of each of the elements below. Which of the atoms has the same valence as carbon (12C )? A) 7N nitrogen B) 9F flourine C) 10Ne neon D) 12Mg magnesium E) 14Sisilicon Answer: E Topic: Concept 2.2 Skill: Application/Analysis 22) Two atoms appear to have the same mass number. These atoms A) must have the same atomic number. B) must have the same number of electrons. C) must have the same chemical properties. D) must have the same number of protons + neutrons. E) must have the same atomic number, the same number of protons + neutrons, the same number of electrons, and the same chemical properties. Answer: D Topic: Concept 2.2 Skill: Synthesis/Evaluation 23) Fluorine has an atomic number of 9 and a mass number of 19. How many electrons are needed to complete the valence shell of a fluorine atom? A) 1 B) 3 C) 0 D) 7 E) 9 Answer: A Topic: Concept 2.2 Skill: Knowledge/Comprehension 7 Copyright © 2011 Pearson Education, Inc. 24) What is the maximum number of electrons in a single 2 p orbital of an atom? A) 1 B) 2 C) 3 D) 4 E) 5 Answer: B Topic: Concept 2.2 Skill: Knowledge/Comprehension 25) The organic molecules in living organisms have a measurably lower ratio of carbon-13/carbon-12, two stable isotopes of carbon that comprise approximately 1.1% and 98.9% of atmospheric carbon, respectively. What is a reasonable explanation for this phenomenon? A) Photosynthesis preferentially uses carbon dioxide molecules with carbon-12, and the lower carbon13/carbon-12 ratio propagates through the food chain. B) Carbon dioxide molecules with carbon-13 stay in the upper atmosphere and are less available to terrestrial plants and algae. C) Carbon-13 has a different valence electron configuration and is therefore less chemically reactive than carbon-12. D) Oxygen atoms preferentially react with carbon-13, thereby enriching the atmosphere with carbon dioxide molecules containing carbon-13 atoms. E) Carbon dioxide molecules containing carbon-13 are heavier and sink into the ocean depths, making them less available to living organisms. Answer: A Topic: Concepts 2.2, 2.4 Skill: Synthesis/Evaluation 26) Phosphorus-32, a radioactive isotope of phosphorus-31 (atomic number 15), undergoes a form of radioactive decay whereby a neutron turns into a proton and emits radiation in the form of an electron. What is the product of such radioactive decay of phosphorus-32? A) phosphorus-31 B) a positively charged phosphorus-31 ion C) a negatively charged phosphorus-32 ion D) sulfur-32 (atomic number 16) E) the conversion of the phosphorus-32 atom into pure energy Answer: D Topic: Concept 2.2 Skill: Application/Analysis 27) An atom with atomic number 12 would have what type of chemical behavior in bonding with other elements? A) It would form ions with a +1 charge. B) It would form ions with a +2 charge. C) It would form ions with a -1 charge. D) It would form ions with a -2 charge. E) It would form two covalent bonds with other atoms. Answer: B Topic: Concept 2.3 Skill: Application/Analysis 8 Copyright © 2011 Pearson Education, Inc. 28) If a salamander relied on hydrogen bonds to cling to surfaces, what type of surface would cause the most problems for this animal? A) a surface coated with a thin film of water B) a surface made with carbon and hydrogen atoms covalently bonded together C) a surface made with carbon, hydrogen, and oxygen atoms covalently bonded together D) a surface made with carbon, hydrogen, nitrogen, and oxygen atoms covalently bonded together E) a surface made with silicon and oxygen atoms covalently bonded together Answer: B Topic: Concept 2.3 Skill: Synthesis/Evaluation 29) A covalent chemical bond is one in which A) electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged. B) protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms. C) outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms. D) outer-shell electrons of one atom are transferred to fill the inner electron shell of another atom. E) an electron occupies a hybrid orbital located between the nuclei of two atoms. Answer: C Topic: Concept 2.3 Skill: Knowledge/Comprehension 30) If an atom of sulfur (atomic number 16) were allowed to react with atoms of hydrogen (atomic number 1), which of the molecules below would be formed? A) S H B) H S H C) H S H | H D) H | H S H | H E) H S H Answer: B Topic: Concept 2.3 Skill: Application/Analysis 9 Copyright © 2011 Pearson Education, Inc. 31) What is the maximum number of covalent bonds an element with atomic number 8 can make with hydrogen? A) 1 B) 2 C) 3 D) 4 E) 6 Answer: B Topic: Concept 2.3 Skill: Knowledge/Comprehension 32) Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)? A) Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge. B) The nitrogen atom has a strong positive charge; each hydrogen atom has a strong positive charge. C) Each hydrogen atom has a slight negative charge; the nitrogen atom has a strong positive charge. D) The nitrogen atom has a slight positive charge; each hydrogen atom has a slight negative charge. E) There are covalent bonds between the hydrogen atoms and polar bonds between each hydrogen atom and the nitrogen atom. Answer: A Topic: Concept 2.3 Skill: Knowledge/Comprehension 33) When two atoms are equally electronegative, they will interact to form A) hydrogen bonds. B) van der Waals interactions. C) polar covalent bonds. D) nonpolar covalent bonds. E) ionic bonds. Answer: D Topic: Concept 2.3 Skill: Knowledge/Comprehension 34) What results from an unequal sharing of electrons between atoms? A) a nonpolar covalent bond B) a polar covalent bond C) an ionic bond D) a hydrogen bond E) a hydrophobic interaction Answer: B Topic: Concept 2.3 Skill: Knowledge/Comprehension 10 Copyright © 2011 Pearson Education, Inc. 35) A covalent bond is likely to be polar when A) one of the atoms sharing electrons is much more electronegative than the other atom. B) the two atoms sharing electrons are equally electronegative. C) oxygen is one of the two atoms sharing electrons. D) one of the atoms has absorbed more energy than the other atom. E) the two atoms sharing electrons are different elements. Answer: A Topic: Concept 2.3 Skill: Knowledge/Comprehension 36) Which of the following molecules contains the most polar covalent bond? A) H2 B) O2 C) CO2 D) H2O E) CH4 Answer: D Topic: Concept 2.3 Skill: Knowledge/Comprehension 37) In comparing covalent bonds and ionic bonds, which of the following would you expect? A) An atom can form covalent bonds with multiple partner atoms, but only a single ionic bond with a single partner atom. B) Covalent bonds and ionic bonds occupy opposite ends of a continuous spectrum, from nearly equal to completely unequal sharing of electrons. C) Both involve electrical attraction between the electrons of one atom and the nucleus of the other atom. D) Ionic interactions remain when covalent bonds are broken in water. Ionic bonds are much stronger than covalent bonds. Answer: B Topic: Concept 2.3 Skill: Synthesis/Evaluation 38) What is the difference between covalent bonds and ionic bonds? A) Covalent bonds are formed between atoms to form molecules; ionic bonds are formed between atoms to form compounds. B) Covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms. C) Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms. D) Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between atoms. E) Covalent bonds involve the transfer of electrons between atoms; ionic bonds involve the sharing of electrons between atoms. Answer: C Topic: Concept 2.3 Skill: Knowledge/Comprehension 11 Copyright © 2011 Pearson Education, Inc. 39) In ammonium chloride salt (NH4Cl) the anion is a single chloride ion, Cl. What is the cation of NH4Cl? A) N, with a charge of +1 B) NH, with a charge of +1 C) H3, with a charge of +1 D) NH4, with a charge of +1 E) NH4, with a charge of +4 Answer: D Topic: Concept 2.3 Skill: Knowledge/Comprehension 40) The atomic number of chlorine is 17. The atomic number of magnesium is 12. What is the formula for magnesium chloride? A) MgCl B) MgCl2 C) Mg2Cl D) Mg2Cl2 E) MgCl3 Answer: B Topic: Concept 2.3 Skill: Application/Analysis 41) How many electron pairs are shared between carbon atoms in a molecule that has the formula C2H4? A) 0 B) 1 C) 2 D) 3 E) 4 Answer: C Topic: Concept 2.3 Skill: Application/Analysis 42) Which bond or interaction would be difficult to disrupt when compounds are put into water? A) covalent bond B) hydrogen bond C) van der Waals interaction D) ionic bond E) either covalent bonds or ionic bonds Answer: A Topic: Concept 2.3 Skill: Application/Analysis 12 Copyright © 2011 Pearson Education, Inc. 43) Which of the following explains most specifically the attraction of water molecules to one another? A) nonpolar covalent bond B) polar covalent bond C) ionic bond D) hydrogen bond E) hydrophobic interaction Answer: D Topic: Concept 2.3 Skill: Knowledge/Comprehension 44) Van der Waals interactions result when A) hybrid orbitals overlap. B) electrons are not symmetrically distributed in a molecule. C) molecules held by ionic bonds react with water. D) two polar covalent bonds react. E) a hydrogen atom loses an electron. Answer: B Topic: Concept 2.3 Skill: Knowledge/Comprehension 45) What bonding or interaction is most likely to occur among a broad array of molecules of various types (polar, nonpolar, hydrophilic, hydrophobic)? A) covalent bonding B) polar covalent bonding C) ionic bonding D) hydrogen bonding E) van der Waals interactions Answer: E Topic: Concept 2.3 Skill: Synthesis/Evaluation 46) Which of the following is not considered to be a weak molecular interaction? A) a covalent bond B) a van der Waals interaction C) an ionic bond in the presence of water D) a hydrogen bond E) both a hydrogen bond and a covalent bond Answer: A Topic: Concept 2.3 Skill: Knowledge/Comprehension 13 Copyright © 2011 Pearson Education, Inc. 47) Which of the following would be regarded as compounds? A) H2O, O2, and CH4 B) H2O and O2 C) O2 and CH4 D) CH4 and O2, but not H2O E) H2O and CH4, but not O2 Answer: E Topic: Concept 2.3 Skill: Application/Analysis 48) What is the maximum number of hydrogen atoms that can be covalently bonded in a molecule containing two carbon atoms? A) 2 B) 3 C) 4 D) 6 E) 8 Answer: D Topic: Concept 2.3 Skill: Application/Analysis 49) Which of the following is true for this reaction? 3 H2 + N2 ↔ 2 NH3 A) The reaction is nonreversible. B) Hydrogen and nitrogen are the reactants of the reverse reaction. C) Hydrogen and nitrogen are the products of the forward reaction. D) Ammonia is being formed and decomposed. E) Hydrogen and nitrogen are being decomposed. Answer: D Topic: Concept 2.4 Skill: Knowledge/Comprehension 50) Which of the following correctly describes chemical equilibrium? A) Forward and reverse reactions continue with no effect on the concentrations of the reactants and products. B) Concentrations of products are higher than the concentrations of the reactants. C) Forward and reverse reactions have stopped so that the concentration of the reactants equals the concentration of the products. D) Reactions stop only when all reactants have been converted to products. E) There are equal concentrations of reactants and products, and the reactions have stopped. Answer: A Topic: Concept 2.4 Skill: Knowledge/Comprehension 14 Copyright © 2011 Pearson Education, Inc. 51) Which of the following correctly describes any reaction that has reached chemical equilibrium? A) The concentration of the reactants equals the concentration of the products. B) The rate of the forward reaction is equal to the rate of the reverse reaction. C) All of the reactants have been converted to the products of the reaction. D) All of the products have been converted to the reactants of the reaction. E) Both the forward and the reverse reactions have stopped with no net effect on the concentration of the reactants and the products. Answer: B Topic: Concept 2.4 Skill: Knowledge/Comprehension 52) Which of these systems is least likely to be at chemical equilibrium? A) a test tube of living cells B) a test tube of organic molecules, kept in the freezer C) a test tube of dry organic molecules, kept at room temperature D) a test tube of organic molecules dissolved in water, kept at room temperature E) a test tube of dead cells in water, kept at room temperature Answer: A Topic: Concept 2.4 Skill: Synthesis/Evaluation 15 Copyright © 2011 Pearson Education, Inc. Art Questions 53) Refer to the figure above (first three rows of the periodic table). If life arose on a planet where carbon is absent, which element might fill the role of carbon? A) boron B) silicon C) nitrogen D) aluminum E) phosphorus Answer: B Topic: Concept 2.2 Skill: Synthesis/Evaluation 54) Which drawing in the figure above depicts the electron configuration of an element with chemical properties most similar to Helium (2He)? A) A B) B C) C D) D E) E Answer: E Topic: Concept 2.2 Skill: Application/Analysis 16 Copyright © 2011 Pearson Education, Inc. 55) Which drawing in the figure above depicts the electron configuration of an atom that can form covalent bonds with two hydrogen atoms? A) A B) B C) C D) D E) E Answer: C Topic: Concept 2.3 Skill: Application/Analysis 56) Which drawing in the figure above depicts the electron configuration of an atom capable of forming three covalent bonds with other atoms? A) A B) B C) C D) D E) E Answer: B Topic: Concept 2.3 Skill: Application/Analysis 57) Which drawing in the figure above is of the electron configuration of a sodium 11Na+ ion? A) A B) B C) C D) D E) E Answer: E Topic: Concept 2.3 Skill: Application/Analysis 58) Which drawing in the figure above depicts the most electronegative atom? A) A B) B C) C D) D E) E Answer: D Topic: Concept 2.3 Skill: Knowledge/Comprehension 17 Copyright © 2011 Pearson Education, Inc. 59) Which drawing in the figure above depicts an atom with a valence of 3? A) A B) B C) C D) D E) E Answer: B Topic: Concept 2.2 Skill: Knowledge/Comprehension 60) Which drawing in the figure above depicts an atom with a valence of 2? A) A B) B C) C D) D E) E Answer: C Topic: Concept 2.2 Skill: Knowledge/Comprehension 61) In the figure above, how many electrons does nitrogen have in its valence shell? A) 2 B) 5 C) 7 D) 8 E) 14 Answer: B Topic: Concept 2.2 Skill: Knowledge/Comprehension 62) In the figure above, how many unpaired electrons does phosphorus have in its valence shell? A) 15 B) 2 C) 3 D) 7 E) 5 Answer: C Topic: Concept 2.2 Skill: Knowledge/Comprehension 18 Copyright © 2011 Pearson Education, Inc. 63) How many neutrons are present in the nucleus of a phosphorus-32 (32P) atom (see the figure above)? A) 5 B) 15 C) 16 D) 17 E) 32 Answer: D Topic: Concept 2.2 Skill: Knowledge/Comprehension 64) How many electrons does an atom of sulfur have in its valence shell (see the figure above)? A) 4 B) 6 C) 8 D) 16 E) 32 Answer: B Topic: Concept 2.2 Skill: Knowledge/Comprehension 65) Based on electron configuration, which of these elements in the figure above would exhibit a chemical behavior most like that of oxygen? A) carbon B) hydrogen C) nitrogen D) sulfur E) phosphorus Answer: D Topic: Concept 2.2 Skill: Application/Analysis 66) The illustration above shows a representation of formic acid. A formic acid molecule A) will form hydrogen bonds with water molecules. B) has a tetrahedral configuration of hybrid electron orbitals for the carbon atom. C) consists of largely nonpolar covalent bonds. D) is held together by hydrogen bonds. E) has a tetrahedral shape and will form hydrogen bonds with water molecules. Answer: A Topic: Concept 2.3 Skill: Synthesis/Evaluation 19 Copyright © 2011 Pearson Education, Inc. 67) What results from the chemical reaction illustrated above? A) a cation with a net charge of +1 B) a cation with a net charge of -1 C) an anion with a net charge of +1 D) an anion with a net charge of -1 E) a cation with a net charge of +1 and an anion with a net charge of -1 Answer: E Topic: Concept 2.3 Skill: Knowledge/Comprehension 68) What is the atomic number of the cation formed in the reaction illustrated above? A) 1 B) 8 C) 10 D) 11 E) 16 Answer: D Topic: Concept 2.3 Skill: Application/Analysis 69) What causes the shape of the molecule shown above? A) the configuration of the 2 p orbitals in the carbon atom B) the configuration of the 1 s orbital in the carbon atom C) the configuration of the sp hybrid orbitals of the electrons shared between the carbon and hydrogen atoms D) the packing of the carbon and hydrogen atoms in a crystal lattice E) hydrogen bonding configurations between the carbon and hydrogen atoms Answer: C Topic: Concept 2.3 Skill: Knowledge/Comprehension 20 Copyright © 2011 Pearson Education, Inc. 70) In the methane molecule shown in the figure above, bonds have formed that include both the s orbital valence electrons of the hydrogen atoms and the p orbital valence electrons of the carbon. The electron orbitals in these bonds are said to be A) double orbitals. B) tetrahedral orbitals. C) complex orbitals. D) hybrid orbitals. E) polar orbitals. Answer: D Topic: Concept 2.3 Skill: Knowledge/Comprehension 21 Copyright © 2011 Pearson Education, Inc. 71) Which one of the atoms shown would be most likely to form a cation with a charge of +1? A) B) C) D) E) Answer: A Topic: Concept 2.3 Skill: Application/Analysis 22 Copyright © 2011 Pearson Education, Inc. 72) Which one of the atoms shown would be most likely to form an anion with a charge of -1? A) B) C) D) E) Answer: D Topic: Concept 2.3 Skill: Application/Analysis 23 Copyright © 2011 Pearson Education, Inc. 73) Which of the following pairs of atoms would be most likely to form a polar covalent bond? A) B) C) D) E) Answer: A Topic: Concept 2.3 Skill: Application/Analysis 24 Copyright © 2011 Pearson Education, Inc. 74) Which of the following pairs of atoms would be most likely to form an ionic bond? A) B) C) D) E) Answer: B Topic: Concept 2.3 Skill: Application/Analysis 25 Copyright © 2011 Pearson Education, Inc. Scenario Question 75) A group of molecular biologists is trying to synthesize a new artificial compound to mimic the effects of a known hormone that influences sexual behavior. They have turned to you for advice. Which of the following compounds is most likely to mimic the effects of the hormone? A) a compound with the same number of carbon atoms as the hormone B) a compound with the same molecular mass (measured in daltons) as the hormone C) a compound with the same three-dimensional shape as part of the hormone D) a compound with the same number of orbital electrons as the hormone E) a compound with the same number of hydrogen and nitrogen atoms as the hormone Answer: C Topic: Concept 2.4 Skill: Application/Analysis End-of-Chapter Questions The following questions are from the end-of-chapter “Test Your Understanding” section in Chapter 2 of the textbook. 76) In the term trace element, the modifier trace means that A) the element is required in very small amounts. B) the element can be used as a label to trace atoms through an organism's metabolism. C) the element is very rare on Earth. D) the element enhances health but is not essential for the organism's long-term survival. E) the element passes rapidly through the organism. Answer: A Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 77) Compared with 31P, the radioactive isotope 32P has A) a different atomic number. B) a different charge. C) one more proton. D) one more electron. E) one more neutron. Answer: E Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 78) The reactivity of an atom arises from A) the average distance of the outermost electron shell from the nucleus. B) the existence of unpaired electrons in the valence shell. C) the sum of the potential energies of all the electron shells. D) the potential energy of the valence shell. E) the energy difference between the s and p orbitals. Answer: B Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 26 Copyright © 2011 Pearson Education, Inc. 79) Which statement is true of all atoms that are anions? A) The atom has more electrons than protons. B) The atom has more protons than electrons. C) The atom has fewer protons than does a neutral atom of the same element. D) The atom has more neutrons than protons. E) The net charge is 1-. Answer: A Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 80) Which of the following statements correctly describes any chemical reaction that has reached equilibrium? A) The concentrations of products and reactants are equal. B) The reaction is now irreversible. C) Both forward and reverse reactions have halted. D) The rates of the forward and reverse reactions are equal. E) No reactantsremain. Answer: D Topic: End-of-Chapter Questions Skill: Knowledge/Comprehension 81) We can represent atoms by listing the number of protons, neutrons, and electrons for example, 2p+; 2n0; 2e- for helium. Which of the following represents the 18O isotope of oxygen? A) 6p+, 8n0, 6eB) 8p+, 10n0, 8eC) 9p+, 9n0, 9eD) 7p+, 2n0, 9eE) 10p+, 8n0, 9eAnswer: B Topic: End-of-Chapter Questions Skill: Application/Analysis 82) The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valence electrons in a sulfur atom, predict the molecular formula of the compound: A) HS B) HS2 C) H2S D) H3S2 E) H4S Answer: C Topic: End-of-Chapter Questions Skill: Application/Analysis 27 Copyright © 2011 Pearson Education, Inc. 83) What coefficients must be placed in the following blanks so that all atoms are accounted for in the products? C6H12O6 → C2H6O + CO2 A) 1; 2 B) 3; 1 C) 1; 3 D) 1; 1 E) 2; 2 Answer: E Topic: End-of-Chapter Questions Skill: Application/Analysis 1 Copyright © 2011 Pearson Education, Inc. Campbell's Biology, 12e Chapter 3 Water and Life Life evolved in the ocean, and the chemistry of life occurs in an aqueous environment. These questions explore the properties of water that are important to sustain life’s chemical processes, organismal physiology, and interactions of organisms with their environment. Quantitative properties such as heat content, molarity, and pH are also addressed. A few questions address how human activities affect the global environment through acid rain and acidification of the ocean. Multiple-Choice Questions 1) In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by A) hydrogen bonds. B) nonpolar covalent bonds. C) polar covalent bonds. D) ionic bonds. E) van der Waals interactions. Answer: C Topic: Concept 3.1 Skill: Knowledge/Comprehension 2) The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called? A) a covalent bond B) a hydrogen bond C) an ionic bond D) a hydrophilic bond E) a van der Waals interaction Answer: B Topic: Concept 3.1 Skill: Knowledge/Comprehension 3) The partial negative charge in a molecule of water occurs because A) the oxygen atom acquires an additional electron. B) the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus. C) the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms. D) the oxygen atom forms hybrid orbitals that distribute electrons unequally around the oxygen nucleus. E) one of the hydrogen atoms donates an electron to the oxygen atom. Answer: B Topic: Concept 3.1 Skill: Knowledge/Comprehension 2 Copyright © 2011 Pearson Education, Inc. 4) Sulfur is in the same column of the periodic table as oxygen, but has electronegativity similar to carbon. Compared to water molecules, molecules of H2S A) will ionize more readily. B) will have greater cohesion to other molecules of H2S. C) will have a greater tendency to form hydrogen bonds with each other. D) will have a higher capacity to absorb heat for the same change in temperature. E) will not form hydrogen bonds with each other. Answer: E Topic: Concept 3.1 Skill: Synthesis/Evaluation 5) Water molecules are able to form hydrogen bonds with A) compounds that have polar covalent bonds. B) oils. C) oxygen gas (O2) molecules. D) chloride ions. E) any compound that is not soluble in water. Answer: A Topic: Concept 3.1 Skill: Application/Analysis 6) Which of the following effects is produced by the h