This Document Contains Chapters 1 to 2 Chapter 1: Introduction: Evolution and the Foundations of Biology 1.1 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 2) Organisms interact with their environments, exchanging matter and energy. For example, plant chloroplasts convert the energy of sunlight to A) the energy of motion. B) carbon dioxide and water. C) chemical energy. D) oxygen. E) kinetic energy. Answer: C 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 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 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 6) 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 7) 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 8) An 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 9) 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 10) 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 11) 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-heritable traits that enhance their survival in the local environment. B) non-heritable traits that enhance their reproductive success in the local environment. C) non-heritable traits that enhance their survival and reproductive success in the local environment. D) heritable traits that enhance their survival and reproductive success in the local environment. E) heritable traits that decrease their survival and reproductive success in the local environment. Answer: D 12) 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 13) 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) reductionism. C) the hierarchy of the biological organization of life. D) natural selection. E) feedback inhibition. Answer: D 14) 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 15) 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 explains how evolution takes place. E) He observed that organisms produce large numbers of offspring. Answer: D 16) 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 17) What is the major distinguishing characteristic of fungi? A) gaining nutrition through ingestion B) being sedentary C) being prokaryotic D) absorbing nutrients E) being decomposers of dead organisms Answer: D 18) Imagine there is a species-specific fishing regulation that mandates only adult fish of this species that are 75 cm or longer may be kept and shorter fish must be released. Based on your knowledge of natural selection, you would predict that the average length of the adult fish population will A) remain unchanged. B) gradually decline. C) rapidly decline. D) gradually increase. E) rapidly increase. Answer: B 19) Which of the following taxonomic categories is least likely to be later revised for a particular organism? A) kingdom B) class C) order D) phylum E) species Answer: E 20) When applying the process of science, which of these is tested? A) a conclusion B) a result C) an observation D) a hypothesis E) a control group Answer: D 21) 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 22) 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 23) 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 24) 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 25) 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 26) 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 organisms, 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 27) 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 ensuring that everyone gets the same results. 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 28) Why is it important that an experiment include a control group? A) The researcher predetermines the results for the control group. 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 29) 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. seeking to identify the pigments present in a leaf 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 30) 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 1.2 End-of-Chapter Questions 1) All the organisms on your campus make up A) an ecosystem. B) a community. C) a population. D) an experimental group. E) a domain. Answer: B 2) Which of the following best demonstrates the unity among all organisms? A) identical DNA sequences B) descent with modification C) the structure and function of DNA D) natural selection E) emergent properties Answer: C 3) 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 4) 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 5) 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 6) 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 Chapter 2: The Chemical Context of Life 2.1 Multiple-Choice Questions 1) About 25 of the 92 natural elements are known to be essential to life. Which 4 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 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 3) Which of the following statements is false? A) Carbon, hydrogen, oxygen, and nitrogen are the most abundant elements of living matter. B) Some naturally occurring elements are toxic to organisms. C) All organisms require the same elements in the same quantities. D) Iron is an example of an element needed by all organisms. E) Approximately one-quarter of the natural elements are essential elements. Answer: C 4) Why is each element unique and different from other elements with respect to its chemical properties? A) Each element has a unique atomic mass. B) Each element has a unique atomic number. C) Each element has a unique number of protons. D) Each element has a unique number of neutrons. E) Each element has different radioactive properties. Answer: C 5) Knowing just the atomic mass of an element allows inferences about which of the following? A) the number of electrons in 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) the number of protons plus electrons in the element Answer: D 6) 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 7) 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 and an atomic number of 14. B) The nitrogen atom has a mass number of approximately 14 and an atomic number of 7. C) The nitrogen atom has a mass number of approximately 14 and an atomic number of 14. D) The nitrogen atom has a mass number of approximately 7 and an atomic number of 21. E) The nitrogen atom has a mass number of approximately 14 and an atomic number of 21 Answer: B 8) 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 9) Carbon-12 is the most common isotope of carbon and has a mass number of 12. However, the atomic mass of carbon is slightly more than 12 daltons. 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 10) One difference between carbon-12 ( C) and carbon-14 ( C) is that carbon-14 has 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 11) 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 12) 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 13) 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 14) 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 15) 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 16) The atomic number of each atom is given to the left of each of the following elements. Which of the atoms has the same valence as carbon ( C)? A) 7N nitrogen B) 9F fluorine C) 10Ne neon D) 12Mg magnesium E) 14Si silicon Answer: E 17) 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 18) Phosphorus-32, a radioactive isotope of phosphorus-31 (atomic number 15), undergoes a form of radioactive decay whereby a neutron turns into a proton, which is retained in the nucleus, 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 19) 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 20) Oxygen has an atomic number of 8 and a mass number of 16. Thus, what is the atomic mass of an oxygen atom? A) approximately 8 grams B) approximately 8 daltons C) approximately 16 grams D) approximately 16 daltons E) approximately 24 grams Answer: D 21) 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 22) 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 23) 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 24) If an atom of sulfur (atomic number 16) were allowed to react with atoms of hydrogen (atomic number 1), which of the following molecules would be formed? A) S–H B) H–S–H C) D) E) H = S = H Answer: B 25) 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 26) 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 full positive charge; each hydrogen atom has a full positive charge. C) Each hydrogen atom has a partial negative charge; the nitrogen atom has a full positive charge. D) The nitrogen atom has a partial positive charge; each hydrogen atom has a partial negative charge. E) There are covalent bonds between the hydrogen atoms and polar bonds between each hydrogen atom and the nitrogen atom. Answer: A 27) 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 28) 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) radioactive decay E) a hydrophobic interaction Answer: B 29) 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 30) Which of the following molecules contains the most polar covalent bond? A) H2 B) O2 C) CO2 D) H2O E) CH4 Answer: D 31) 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 32) 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 33) 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 34) 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 35) 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 36) 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 bond or ionic bond Answer: A 37) 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 38) 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 39) Which of the following is (are) 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 40) 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 41) 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 42) 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 43) 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) The concentrations of the 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 44) 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 45) 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 46) 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 47) 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 48) 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 49) 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’s nucleus than around the hydrogen atom’s 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 50) 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 will A) ionize more readily. B) have greater cohesion to other molecules of H2S. C) have a greater tendency to form hydrogen bonds with each other. D) have a higher capacity to absorb heat for the same change in temperature. E) not form hydrogen bonds with each other. Answer: E 51) 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 52) Which of the following effects is produced by the high surface tension of water? A) Lakes don't freeze solid in winter, despite low temperatures. B) A water strider can walk across the surface of a small pond. C) Organisms resist temperature changes, although they give off heat due to chemical reactions. D) Evaporation of sweat from the skin helps to keep people from overheating. E) Water flows upward from the roots to the leaves in plants. Answer: B 53) Which of the following takes place as an ice cube cools a drink? A) Molecular collisions in the drink increase. B) Kinetic energy in the drink decreases. C) A calorie of heat energy is transferred from the ice to the water of the drink. D) The specific heat of the water in the drink decreases. E) Evaporation of the water in the drink increases. Answer: B 54) A dietary Calorie equals 1 kilocalorie. Which of the following statements correctly defines 1 kilocalorie? A) 1,000 calories, or the amount of heat required to raise the temperature of 1 g of water by 1,000°C B) 100 calories, or the amount of heat required to raise the temperature of 100 g of water by 1°C C) 10,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°F D) 1,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°C E) 1,000 calories, or the amount of heat required to raise the temperature of 100 g of water by 100°C Answer: D 55) The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20 kg of water how many degrees Celsius? A) 0.2°C B) 1.0°C C) 2.0°C D) 10.0°C E) 20.0°C Answer: D 56) Liquid water's high specific heat is mainly a consequence of the A) small size of the water molecules. B) high specific heat of oxygen and hydrogen atoms. C) absorption and release of heat when hydrogen bonds break and form. D) fact that water is a poor heat conductor. E) higher density of liquid water than solid water (ice). Answer: C 57) Which type of bond must be broken for water to vaporize? A) ionic bonds B) both hydrogen bonds and ionic bonds C) polar covalent bonds D) hydrogen bonds E) both polar covalent bonds and hydrogen bonds Answer: D 58) Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon? A) the change in density when it condenses to form a liquid or solid B) reactions with other atmospheric compounds C) the release of heat by the formation of hydrogen bonds D) the release of heat by the breaking of hydrogen bonds E) the high surface tension of water Answer: C 59) Why does ice float in liquid water? A) The high surface tension of liquid water keeps the ice on top. B) The ionic bonds between the molecules in ice prevent the ice from sinking. C) Ice always has air bubbles that keep it afloat. D) Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water. E) The crystalline lattice of ice causes it to be denser than liquid water. Answer: D 60) Hydrophobic substances such as vegetable oil are A) nonpolar substances that repel water molecules. B) nonpolar substances that have an attraction for water molecules. C) polar substances that repel water molecules. D) polar substances that have an affinity for water. E) charged molecules that hydrogen-bond with water molecules. Answer: A 61) One mole (mol) of glucose (molecular mass = 180 daltons) is A) 180 × 1023 molecules of glucose. B) 1 kg of glucose dissolved in 1 L of solution. C) the largest amount of glucose that can be dissolved in 1 L of solution. D) 180 kilograms of glucose. E) both 180 grams of glucose and 6.02 × 1023 molecules of glucose. Answer: E 62) How many molecules of glucose (C6H12O6 molecular mass = 180 daltons) would be present in 90 grams of glucose? A) 90 × 1023 B) (6.02/180) × 1023 C) (6.02/90) × 1023 D) (90 × 6.02) × 1023 E) (90/180) × 6.02 × 1023 Answer: E 63) How many molecules of glycerol (C3H8O3; molecular mass = 92) would be present in 1 L of a 1 M glycerol solution? A) 1 × 106 B) 14 × 6.02 × 1023 C) 92 × 6.02 × 1023 D) 6.02 × 1026 E) 6.02 × 1023 Answer: E 64) When an ionic compound such as sodium chloride (NaCl) is placed in water, the component atoms of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl—). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of solute particles (molecules or ions)? A) 1 L of 0.5 M NaCl B) 1 L of 0.5 M glucose C) 1 L of 1.0 M NaCl D) 1 L of 1.0 M glucose E) 1 L of 1.0 M NaCl and 1 L of 1.0 M glucose will contain equal numbers of solute particles. Answer: C 65) The molar mass of glucose is 180 g/mol. Which of the following procedures should you carry out to make a 1 M solution of glucose? A) Dissolve 1 g of glucose in 1 L of water. B) Dissolve 180 g of glucose in 1 L of water. C) Dissolve 180 g of glucose in 180 g of water. D) Dissolve 180 milligrams (mg) of glucose in 1 L of water. E) Dissolve 180 g of glucose in 0.8 L of water, and then add more water until the total volume of the solution is 1 L. Answer: E 66) The molar mass of glucose (C6H12O6) is 180 g/mol. Which of the following procedures should you carry out to make a 0.5 M solution of glucose? A) Dissolve 0.5 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L. B) Dissolve 90 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L. C) Dissolve 180 g of glucose in a small volume of water, and then add more water until the total volume of the solution is 1 L. D) Dissolve 0.5 g of glucose in 1 L of water. E) Dissolve 180 g of glucose in 0.5 L of water. Answer: B 67) You have a freshly prepared 0.1 M solution of glucose in water. Each liter of this solution contains how many glucose molecules? A) 6.02 × 1023 B) 3.01 × 1023 C) 6.02 × 1024 D) 12.04 × 1023 E) 6.02 × 1022 Answer: E 68) The molecular weight of water is 18 daltons. What is the molarity of 1 liter of pure water? (Hint: Note that 1 liter of pure water has a mass of 1 kg.) A) 55.6 M B) 18 M C) 37 M D) 0.66 M E) 1.0 M Answer: A 69) You have a freshly prepared 1 M solution of glucose in water. You carefully pour out a 100-mL sample of that solution. How many glucose molecules are included in that 100-mL sample? A) 6.02 × 1023 B) 3.01 × 1023 C) 6.02 × 1024 D) 12.04 × 1023 E) 6.02 × 1022 Answer: E 70) A strong acid like HCl A) ionizes completely in an aqueous solution. B) increases the pH when added to an aqueous solution. C) reacts with strong bases to create a buffered solution. D) is a strong buffer at low pH. E) both ionizes completely in aqueous solutions and is a strong buffer at low pH. Answer: A 71) Which of the following ionizes completely in solution and is considered to be a strong base (alkali)? A) NaCl B) HCl C) NH3 D) H2CO3 E) NaOH Answer: E 72) A 0.01 M solution of a substance has a pH of 2. What can you conclude about this substance? A) It is a strong acid that ionizes completely in water. B) It is a strong base that ionizes completely in water. C) It is a weak acid. D) It is a weak base. E) It is neither an acid nor a base. Answer: A 73) A given solution contains 0.0001(10-4) moles of hydrogen ions (H+) per liter. Which of the following best describes this solution? A) acidic: will accept H+ from both strong and weak acids B) basic: will accept H+ from both strong and weak acids C) acidic: will give H+ to weak acids, but accept H+ from strong acids D) basic: will give H+ to weak acids, but accept H+ from weak acids E) acidic: will give H+ to both strong and weak acids Answer: C 74) A solution contains 0.0000001(10-7) moles of hydroxyl ions (OH-) per liter. Which of the following best describes this solution? A) acidic: H+ acceptor B) basic: H+ acceptor C) acidic: H+ donor D) basic: H+ donor E) neutral Answer: E 75) What is the pH of a solution with a hydroxyl ion (OH-) concentration of 10-12 M? A) pH 2 B) pH 4 C) pH 10 D) pH 12 E) pH 14 Answer: A 76) What is the pH of a 1-millimolar NaOH solution? A) pH 3 B) pH 8 C) pH 9 D) pH 10 E) pH 11 Answer: E 77) Which of the following solutions would require the greatest amount of base to be added to bring the solution to neutral pH? A) gastric juice at pH 2 B) vinegar at pH 3 C) tomato juice at pH 4 D) black coffee at pH 5 E) household bleach at pH 12 Answer: A 78) What is the hydrogen ion (H+) concentration of a solution of pH 8? A) 8 M B) 8 × 10-6 M C) 0.01 M D) 10-8 M E) 10-6 M Answer: D 79) If the pH of a solution is decreased from 9 to 8, it means that the A) concentration of H+ has decreased to one-tenth (1/10) what it was at pH 9. B) concentration of H+ has increased tenfold (10X) compared to what it was at pH 9. C) concentration of OH- has increased tenfold (10X) compared to what it was at pH 9. D) concentration of OH- has decreased to one-tenth (1/10) what it was at pH 9. E) concentration of H+ has increased tenfold (10X) and the concentration of OH- has decreased to one-tenth (1/10) what they were at pH 9. Answer: E 80) If the pH of a solution is increased from pH 5 to pH 7, it means that the A) concentration of H+ is twice (2X) what it was at pH 5. B) concentration of H+ is one-half (1/2) what it was at pH 5. C) concentration of OH- is 100 times greater than what it was at pH 5. D) concentration of OH- is one-hundredth (0.01X) what it was at pH 5. E) concentration of H+ is 100 times greater and the concentration of OH- is one-hundredth what they were at pH 5. Answer: C 81) One liter of a solution of pH 2 has how many more hydrogen ions (H+) than 1 L of a solution of pH 6? A) 4 times more B) 16 times more C) 40,000 times more D) 10,000 times more E) 100,000 times more Answer: D 82) One liter of a solution of pH 9 has how many more hydroxyl ions (OH-) than 1 L of a solution of pH 4? A) 5 times more B) 32 times more C) 50,000 times more D) 10,000 times more E) 100,000 times more Answer: E 83) Which of the following statements is true about buffer solutions? A) They maintain a constant pH when bases are added to them but not when acids are added to them. B) They maintain a constant pH when acids are added to them but not when bases are added to them. C) They maintain a relatively constant pH of approximately 7 when either acids or bases are added to them. D) They maintain a relatively constant pH when either acids or bases are added to them. E) They are found only in living systems and biological fluids. Answer: D 84) Buffers are substances that help resist shifts in pH by A) releasing H+ to a solution when acids are added. B) donating H+ to a solution when bases are added. C) releasing OH- to a solution when bases are added. D) accepting H+ from a solution when acids are added. E) both donating H+ to a solution when bases are added and accepting H+ when acids are added. Answer: E 85) One of the buffers that contributes to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+). Thus, H2CO3 ↔ HCO3- + H+ If the pH of the blood drops, one would expect A) a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-. B) the concentration of hydroxide ion (OH-) to increase. C) the concentration of bicarbonate ion (HCO3-) to increase. D) the HCO3- to act as a base and remove excess H+ with the formation of H2CO3. E) the HCO3- to act as an acid and remove excess H+ with the formation of H2CO3. Answer: D 86) One of the buffers that contributes to pH stability in human blood is carbonic acid (H2CO3). Carbonic acid is a weak acid that, when placed in an aqueous solution, dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion (H+). Thus, H2CO3 ↔ HCO3- + H+ If the pH of the blood increases, one would expect A) a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3-. B) an increase in the concentration of H2CO3 and a decrease in the concentration of HCO3-. C) a decrease in the concentration of HCO3- and an increase in the concentration of H+. D) an increase in the concentration of HCO3- and a decrease in the concentration of OH-. E) a decrease in the concentration of HCO3- and an increase in the concentration of both H2CO3 and H+. Answer: A 87) Assume that acid rain has lowered the pH of a particular lake to pH 4.0. What is the hydroxyl ion concentration of this lake? A) 1 × 10-10 mol of hydroxyl ion per liter of lake water B) 1 × 10-4 mol of hydroxyl ion per liter of lake water C) 10.0 M with regard to hydroxyl ion concentration D) 4.0 M with regard to hydroxyl ion concentration E) 1 × 10-4 mol of hydroxyl ion per liter of lake water and 4.0 M with regard to hydrogen ion concentration Answer: A 88) Research indicates that acid precipitation can damage certain marine organisms by A) buffering ocean waters. B) decreasing the H+ concentration in oceans. C) increasing the OH- concentration in oceans. D) decreasing the concentration of carbonate ions in oceans. E) both decreasing the H+ concentration and increasing the OH- concentration in oceans. Answer: D 89) Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that A) solution Y has no free hydrogen ions (H+). B) the concentration of hydrogen ions in solution X is 30 times as great as the concentration of hydrogen ions in solution Y. C) the concentration of hydrogen ions in solution Y is 1,000 times as great as the concentration of hydrogen ions in solution X. D) the concentration of hydrogen ions in solution X is 3 times as great as the concentration of hydrogen ions in solution Y. E) the concentration of hydrogen ions in solution X is 1,000 times as great as the concentration of hydrogen ions in solution Y. Answer: E 90) If a solution has a pH of 7, this means that A) there are no H+ ions in the water. B) this is a solution of pure water. C) the concentration of H+ ions in the water equals the concentration of OH- ions in the water. D) this is a solution of pure water, and the concentration of H+ ions in the water is 10-7 M. E) this is a solution of pure water, and the concentration of H+ ions equals the concentration of OH- ions in the water. Answer: C 91) Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O ↔ H2CO3. Carbonic acid (H2CO3) is a weak acid. Respiring cells release CO2 into the bloodstream. What will be the effect on the pH of blood as that blood first comes in contact with respiring cells? A) Blood pH will decrease slightly. B) Blood pH will increase slightly. C) Blood pH will remain unchanged. D) Blood pH will first increase, then decrease as CO2 combines with hemoglobin. E) Blood pH will first decrease, then increase sharply as CO2 combines with hemoglobin. Answer: A 92) A beaker contains 100 mL of NaOH solution at pH = 13. A technician carefully pours into the beaker 10 mL of HCl at pH = 1. Which of the following statements correctly describes the results of this mixing? A) The concentration of Na+ ion will rise. B) The concentration of Cl- ion will be 0.1 M. C) The concentration of undissociated H2O molecules will remain unchanged. D) The pH of the beaker's contents will be neutral. E) The pH of the beaker's contents will decrease. Answer: E 93) Equal volumes (5 mL) of vinegar from a freshly opened bottle are added to each of the following solutions. After complete mixing, which of the mixtures will have the highest pH? A) 100 mL of pure water B) 100 mL of freshly brewed coffee C) 100 mL of household cleanser containing 0.5 M ammonia D) 100 mL of freshly squeezed lemon juice E) 100 mL of tomato juice Answer: C 94) Increased atmospheric CO2 concentrations might have what effect on seawater? A) Seawater will become more acidic, and bicarbonate concentrations will decrease. B) Seawater will become more alkaline, and carbonate concentrations will decrease. C) There will be no change in the pH of seawater, because carbonate will turn to bicarbonate. D) Seawater will become more acidic, and carbonate concentrations will decrease. E) Seawater will become more acidic, and carbonate concentrations will increase. Answer: D 95) How would acidification of seawater affect marine organisms? A) Acidification would increase dissolved carbonate concentrations and promote faster growth of corals and shell-building animals. B) Acidification would decrease dissolved carbonate concentrations and promote faster growth of corals and shell-building animals. C) Acidification would increase dissolved carbonate concentrations and hinder growth of corals and shell-building animals. D) Acidification would decrease dissolved carbonate concentrations and hinder growth of corals and shell-building animals. E) Acidification would increase dissolved bicarbonate concentrations, and cause increased calcification of corals and shellfish. Answer: D 96) One idea to mitigate the effects of burning fossil fuels on atmospheric CO2 concentrations is to pipe liquid CO2 into the ocean at depths of 2,500 feet or greater. At the high pressures at such depths, CO2 is heavier than water. What potential effects might result from implementing such a scheme? A) increased photosynthetic carbon fixation because of the increased dissolved carbon dioxide in the deep water B) increased carbonate concentrations in the deep waters C) increased growth of corals from a change in the carbonate—bicarbonate equilibrium D) no effect because carbon dioxide is not soluble in water E) both increased acidity of the deep waters and changes in the growth of bottom-dwelling organisms with calcium carbonate shells Answer: E 97) If the cytoplasm of a cell is at pH 7, and the mitochondrial matrix is at pH 8, this means that A) the concentration of H+ ions is tenfold higher in the cytoplasm than in the mitochondrial matrix. B) the concentration of H+ ions is tenfold higher in the mitochondrial matrix than in the cytoplasm. C) the concentration of H+ ions in the cytoplasm is 7/8 the concentration in the mitochondrial matrix. D) the mitochondrial matrix is more acidic than the cytoplasm. E) the concentration of H+ ions in the cytoplasm is 8/7 the concentration in the mitochondrial matrix. Answer: A 2.2 Art Questions Figure 2.1 1) Which of the following best describes the relationship between the atoms described in Figure 2.1? 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 Figure 2.2 2) Refer to Figure 2.2 (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 Figure 2.3 3) Which drawing in Figure 2.3 depicts the electron configuration of an element with chemical properties most similar to those of helium (2He)? A) A B) B C) C D) D E) E Answer: E 4) Which drawing in Figure 2.3 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 5) Which drawing in Figure 2.3 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 6) Which drawing in Figure 2.3 is of the electron configuration of a sodium 11Na+ ion? A) A B) B C) C D) D E) E Answer: E 7) Which drawing in Figure 2.3 depicts an atom with a valence of 3? A) A B) B C) C D) D E) E Answer: B 8) Which drawing in Figure 2.3 depicts an atom with a valence of 2? A) A B) B C) C D) D E) E Answer: C Figure 2.4 9) In Figure 2.4, how many electrons does nitrogen have in its valence shell? A) 2 B) 5 C) 7 D) 8 E) 14 Answer: B 10) In Figure 2.4, how many unpaired electrons does phosphorus have in its valence shell? A) 15 B) 2 C) 3 D) 7 E) 5 Answer: C 11) How many neutrons are present in the nucleus of a phosphorus-32 (32P) atom (see Figure 2.4)? A) 5 B) 15 C) 16 D) 17 E) 32 Answer: D 12) How many electrons does an atom of sulfur have in its valence shell (see Figure 2.4)? A) 4 B) 6 C) 8 D) 16 E) 32 Answer: B 13) Based on electron configuration, which of these elements in Figure 2.4 would exhibit a chemical behavior most like that of oxygen? A) carbon B) hydrogen C) nitrogen D) sulfur E) phosphorus Answer: D Figure 2.5 14) Figure 2.5 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 Figure 2.6 15) What results from the chemical reaction illustrated in Figure 2.6? 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 16) What is the atomic number of the cation formed in the reaction illustrated in Figure 2.6? A) 1 B) 8 C) 10 D) 11 E) 16 Answer: D Figure 2.7 17) What causes the shape of the molecule shown in Figure 2.7? 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 Figure 2.8 18) In the methane molecule shown in Figure 2.8, 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 19) 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 20) 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 21) Which of the following pairs of atoms would be most likely to form a polar covalent bond? A) B) C) D) E) Answer: A 22) Which one of the following pairs of atoms would be most likely to form ions and thus an ionic bond? A) B) C) D) E) Answer: B Figure 2.9 23) Based on your knowledge of the polarity of water molecules, the solute molecule depicted in Figure 2.9 is most likely A) positively charged. B) negatively charged. C) without charge. D) hydrophobic. E) nonpolar. Answer: A Figure 2.10 24) How many grams would be equal to 1 mol of the compound shown in Figure 2.10? (carbon = 12, oxygen = 16, hydrogen = 1) A) 29 B) 30 C) 60 D) 150 E) 342 Answer: C 25) How many grams of the compound in Figure 2.10 would be required to make 1 L of a 0.5 M solution? (carbon = 12, oxygen = 16, hydrogen = 1) A) 29 B) 30 C) 60 D) 150 E) 342 Answer: B 26) How many grams of the compound in Figure 2.10 would be required to make 2.5 L of a 1 M solution? (carbon = 12, oxygen = 16, hydrogen = 1) A) 29 B) 30 C) 60 D) 150 E) 342 Answer: D 27) A small birthday candle is weighed. It is then lighted and placed beneath a metal can containing 100 mL of water. Careful records are kept as the temperature of the water rises. Data from this experiment are shown on the graph. What amount of heat energy is released in the burning of candle wax? (Note that 1 liter of pure water has a mass of 1 kg.) Figure 2.11 A) 0.5 kilocalories per gram of wax burned B) 5 kilocalories per gram of wax burned C) 10 kilocalories per gram of wax burned D) 20 kilocalories per gram of wax burned E) 50 kilocalories per gram of wax burned Answer: A 28) Identical heat lamps are arranged to shine on identical containers of water and methanol (wood alcohol), so that each liquid absorbs the same amount of energy minute by minute. The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. Which of the following graphs correctly describes what will happen to the temperature of the water and the methanol? A) B) C) D) E) Answer: B 29) Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O ↔ H2CO3. Carbonic acid (H2CO3) is a weak acid. If CO2 is bubbled into a beaker containing pure, freshly distilled water, which of the following graphs correctly describes the results? A) B) C) D) E) Answer: B 2.3 Scenario Questions 1) 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. The biologists 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 2) You have two beakers. One contains pure water, the other contains pure methanol (wood alcohol). The covalent bonds of methanol molecules are nonpolar, so there are no hydrogen bonds among methanol molecules. You pour crystals of table salt (NaCl) into each beaker. Predict what will happen. A) Equal amounts of NaCl crystals will dissolve in both water and methanol. B) NaCl crystals will not dissolve in either water or methanol. C) NaCl crystals will dissolve readily in water but will not dissolve in methanol. D) NaCl crystals will dissolve readily in methanol but will not dissolve in water. E) When the first crystals of NaCl are added to water or to methanol, they will not dissolve; but as more crystals are added, the crystals will begin to dissolve faster and faster. Answer: C 3) You have two beakers. One contains a solution of HCl at pH = 1.0. The other contains a solution of NaOH at pH = 13. Into a third beaker, you slowly and cautiously pour 20 mL of the HCl and 20 mL of the NaOH. After complete stirring, the pH of the mixture will be A) 2.0. B) 12.0. C) 7.0. D) 5.0. E) 9.0. Answer: C 2.4 End-of-Chapter Questions 1) 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 differences between the electron shells. Answer: B 2) 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 reactants remain. Answer: D 3) Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature? A) water's change in density when it condenses B) water's ability to dissolve molecules in the air C) the release of heat by the formation of hydrogen bonds D) the absorption of heat by the breaking of hydrogen bonds E) water's high surface tension Answer: D 4) We can be sure that a mole of table sugar and a mole of vitamin C are equal in their A) mass in daltons. B) mass in grams. C) volume. D) number of atoms. E) number of molecules. Answer: E 5) Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake? A) 4.0 M B) 10−10 M C) 10−4 M D) 104 M E) 4% Answer: C 6) 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 7) 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 8) A slice of pizza has 500 kcal. If we could burn the pizza and use all the heat to warm a 50-L container of cold water, what would be the approximate increase in the temperature of the water? (Note: A liter of cold water weighs about 1 kg.) A) 50°C B) 5°C C) 1°C D) 100°C E) 10°C Answer: E Test Bank for Campbell Biology in Focus Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson, Jane B. Reece 9780321813664, 9780321962751, 9780134710679
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