Test Bank For ORGANIC CHEMISTRY 8Th Edition International Edition by John E. McMurry -

Chapter 1—Structure and Bonding SHORT ANSWER 1. Give the ground-state electron configuration for carbon (atomic number 6). ANS: 1s22s22px12py1 or 1s22s22p2 2. Give the ground-state electron configuration for fluorine (atomic number 9). ANS: 1s22s22px2 2py2 2pz1 or 1s22s22p5 3.Give the ground-state electron configuration for magnesium (atomic number 12). ANS: 1s22s22p63s2 4. How many electrons does silicon have in its valence shell? ANS: four Exhibit 1-1 Write valid Lewis (electron-dot) structures for each formula below. Show all electrons as dots and show all non-bonding electrons. 5. C2Cl4 ANS: 6. CO2 ANS: 7. CH4O tetrachloroethylene carbon dioxide methanol 1 Structure and Bonding ANS: Exhibit 1-2 Consider the structure of urea, shown below, to answer the following question(s). 8. Refer to Exhibit 1-2. Fill in any non-bonding valence electrons that are missing from the line-bond structure. ANS: 9. sp3 hybridized sp2 hybridized sp hybridized not hybridized ANS: b 10. 109.5 120 180 not predictable ANS: b 2 Refer to Exhibit 1-2. The carbon atom in urea is: Refer to Exhibit 1-2. The predicted NH2C=O bond angle in urea is: Exhibit 1-3 Determine the hybridization for the indicated atoms in each structure below. 11. Refer to Exhibit 1-3. The hybridization of this oxygen atom (A) is ______. ANS: sp2 12. Refer to Exhibit 1-3. The hybridization of this oxygen atom (B) is ______. ANS: sp3 13. Refer to Exhibit 1-3. The hybridization of this carbon atom (C) is ______. ANS: sp3 14. Refer to Exhibit 1-3. The hybridization of this carbon atom (D) is ______. ANS: sp 15. Chapter 1 The molecular formula C2H4O can be converted into three-line bond (Kekulé) structures that are consistent with valence rules. Which one of the Kekulé structures is not consistent with valence rules? Explain why the structure you chose in part a is not consistent with valence rules. ANS: d The carbon bonded to the oxygen atom in structure d is pentavalent; it has 10 valence electrons. Carbon can only have eight valence electrons. In addition, the other carbon has only six valence electrons when it would prefer to have eight. 3 Structure and Bonding 16. The original question was combined with #15. This placeholder question is here to maintain the integrity of the numbering system between the printed copy and ExamView. Therefore, it has been marked "do not use on test" in ExamView's question information dialog. As a result, this placeholder question is automatically prevented from being chosen as a test question. ANS: Answer not provided. 17. Convert the following structure to a skeletal drawing and give its molecular formula. ANS: Molecular formula: C5H7Br 18. Draw an orbital picture for acetylene, C2H2. Clearly label each bond type and indicate the type of orbitals involved in each bond. ANS: 4 Exhibit 1-4 Propose possible structures for a molecule that meets each of the following descriptions. 19. Refer to Exhibit 1-4. Contains two sp3 hybridized carbons and two sp hybridized carbons. ANS: 20. Refer to Exhibit 1-4. Contains one sp3 hybridized carbon and two sp2 hybridized carbons. ANS: 21. Convert the following molecular model into a condensed structure and a skeletal structure. ANS: 22. Convert the following molecular model into a condensed structure and a skeletal structure. Chapter 1 5 Structure and Bonding ANS: 23. Convert the following molecular model into a condensed structure and a skeletal structure. ANS: or more specifically; 24. Indicate the hybridization on each of the carbon atoms indicated with a number in the molecular model shown. ANS: Carbon 1: sp3 Carbon 2: sp2 6 25. Draw the orbital diagram showing the ground-state electron configuration of sulfur. ANS: 26. Fill in any nonbonding valence electrons that are missing from the following structural representation of the amino acid cysteine. ANS: 27. There are two substances with the molecular formula C2H7N. Draw them and describe how they differ. ANS: The two structures differ in the number of hydrogen atoms and carbon atoms bonded to the nitrogen atom. The first structure contains the carbon atoms bonded in a two carbon chain while in the second structure the two carbons atoms are isolated from each other by the nitrogen atom. Chapter 1 7 Structure and Bonding MULTIPLE CHOICE 1. Overlap of the two atomic orbitals shown could result in a:  bond bond  or  depending on the direction of the overlap. ANS: C 2. Hybridization of the atomic orbitals shown would result in: sp3 hybridization sp2 hybridization sp hybridization ANS: B 3. Which of the following represents a hybrid orbital? 8 ANS: D 4. What type of hybridization is exhibited by carbon in the following substance?: sp3 hybridization sp2 hybridization sp hybridization ANS: B 5. What type of hybridization is exhibited by carbon in the following substance?: sp3 hybridization sp2 hybridization sp hybridization ANS: C 6. What type of hybridization is exhibited by the nitrogen atom in the following substance and how many lone pairs are present on the nitrogen?: sp3 hybridization and 1 lone pair sp2 hybridization and l lone pair sp hybridization and 1 lone pair sp3 hybridization and 2 lone pairs Chapter 1 9 Structure and Bonding sp2 hybridization and 2 lone pairs sp hybridization and 2 lone pairs ANS: A 7. If all the missing bonds in the following structure are sigma bonds to hydrogen atoms, how many hydrogen atoms are missing from this structure? Atoms other than carbon are labeled. 7 10 12 14 None of these is the correct number. ANS: E 10 Chapter 2—Polar Covalent Bonds; Acids and Bases SHORT ANSWER Exhibit 2-1 Give the letter of the term that best matches the given Brønsted-Lowry Acid Brønsted-Lowry Base Lewis Acid Lewis Base Electronegativity 1. _____ Any species that can accept electrons. ANS: c definition. Ionic Bond Covalent Bond Polar-Covalent Bond Hydrophobic Hydrophilic 2. _____ A bond between two atoms differing in electronegativity by 0.5  2. ANS: h 3. _____ A term used to describe a "water loving" species. ANS: j 4. _____ A compound that can donate a proton. ANS: a PTS: 1 5._____ The ability of an atom to attract the shared electrons in a covalent bond. ANS: e 6. _____ A term used to describe a "water fearing" species. ANS: i 1 Polar Covalent Bonds: Acids and Bases 7. _____ Any species that can donate electrons. ANS: d 8. _____ A bond between two atoms differing in electronegativity by < 0.5. ANS: g 9. _____ A compound that can accept a proton. ANS: b 10. _____ A bond between two atoms differing in electronegativity by > 2. ANS: f Exhibit 2-2 Calculate the formal charges on the indicated atoms in each compound below. 11. Refer to Exhibit 2-2. The formal charge on phosphorous (A) is ______. ANS: +1 12. Refer to Exhibit 2-2. The formal charge on oxygen (B) is ______. ANS: 1 13. Refer to Exhibit 2-2. The formal charge on carbon (C) is ______. ANS: 1 2 14. Refer to Exhibit 2-2. The formal charge on oxygen (D) is ______. ANS: +1 Exhibit 2-3 Phenylalanine is an amino acid that is essential to human nutrition. The representation below shows the structure of phenylalanine at physiological pH. Consider this structure to answer the following question(s). 5.Refer to Exhibit 2-3. Assign any formal charges to atoms in this representation of phenylalanine. ANS: 16. Refer to Exhibit 2-3. The oxygen atom labeled A. has ______ non-bonding electrons. ANS: four 17. Refer to Exhibit 2-3. The oxygen atom labeled B. has _____ bonding electrons. ANS: two Chapter 2 3 Polar Covalent Bonds: Acids and Bases Exhibit 2-4 Use the convention and the crossed arrow to show the direction of the expected polarity of the indicated bonds in the following compounds. 18. Refer to Exhibit 2-4. The CF bond in fluorobenzene, ANS: 19. Refer to Exhibit 2-4. The CSi bond in tetramethylsilane, (CH3)4Si ANS: 20. Refer to Exhibit 2-4. The CO bond in furan, ANS: Exhibit 2-5 Label the acid, conjugate acid, base, and conjugate base in each reaction below. 21. ANS: 4 Chapter 2 22. ANS: Exhibit 2-6 Refer to the following equation to answer the question(s) below. Place the letter corresponding to the correct answer in the blank. 23. Refer to Exhibit 2-6. The strongest Brønsted-Lowry acid in the equation is ______. ANS: D 24. Refer to Exhibit 2-6. The strongest Brønsted-Lowry base in the equation is ______. ANS: C 25. Refer to Exhibit 2-6. Will this reaction take place as written? Explain. ANS: No, the reaction will not take place as written because the strongest acid reacts with the strongest base to give the weakest conjugate acid and the weakest conjugate base. D (pKa = 15.7) is a stronger acid than A (pKa = 18). 26. An acid with a low pKa: is a weak acid is a strong acid has a weak conjugate base both b and c ANS: d 5 Polar Covalent Bonds: Acids and Bases 27. Circle all the Lewis bases in the group of compounds below. ANS: 28. Put a box around all the Lewis acids in the group of compounds below. ANS: 29. Draw two resonance structures for the species below. ANS: 6 30. Draw two resonance structures for the species below. ANS: 31. Draw two resonance structures for the species below. ANS: Exhibit 2-7 Consider the acidity constants below to answer the following question(s). Chapter 2 ACID phenol STRUCTURE pKa 10.00 16.00 15.74 32. Refer to Exhibit 2-7. Which acid will be almost completely deprotonated by NaOH? ANS: phenol ethanol water CH3CH2OH HOH 7 Polar Covalent Bonds: Acids and Bases 33. Refer to Exhibit 2-7. Which acid has the strongest conjugate base? ANS: Ethanol is the weakest acid (largest pKa) so its conjugate base, ethoxide, CH3CH2O, will be the strongest base. 34. Refer to Exhibit 2-7. Explain why phenol has a much lower pKa than ethanol. ANS: Phenol is more acidic (has a lower pKa) than ethanol because the phenoxide anion is resonance stabilized by the pi electrons in the ring. Ethoxide anion has no resonance stabilization. The negative charge is borne fully by oxygen. Exhibit 2-8 Consider the reaction below to answer the following question(s). 35. Refer to Exhibit 2-8. Using the curved arrow formalism, show the flow of electrons for this reaction. ANS: 8 36. Refer to Exhibit 2-8. Label the acid and the base in the reaction. ANS: Exhibit 2-9 Indole is pleasant smelling in highly dilute solutions and has been used in perfumery. Use the structure of indole, below, to answer the following question(s). 37. Refer to Exhibit 2-9. Indole can function as a Brønsted-Lowry acid in the presence of strong bases. Formulate a reaction, showing electron flow with arrows, that demonstrates this reactivity of indole. ANS: 38. Refer to Exhibit 2-9. Indole can function as a Lewis base in the presence of strong acid. Formulate a reaction, showing electron flow with arrows, that demonstrates this reactivity of indole. ANS: Chapter 2 9 Polar Covalent Bonds: Acids and Bases 39. The condensed structure for dimethyl ether looks symmetrical. However, dimethyl ether has a dipole moment. Draw a structure that explains this and indicate the expected direction of the molecular dipole moment. ANS: Exhibit 2-10 Consider the acid-base reaction below to answer the following question(s). 40. Refer to Exhibit 2-10. Using the curved arrow formalism, show the flow of electrons for this reaction. ANS: 41. Refer to Exhibit 2-10. Write the products of this Lewis acid - base reaction. ANS: 10 42. The following is a representation of the pain reliever, acetaminophen, the active ingredient in Tylenol®. Indicate the positions of any multiple bonds. Atoms other than carbon and hydrogen are labeled. ANS: 43. Use the curved arrow formalism to show the electron flow in the reaction of ammonia with water. ANS: MULTIPLE CHOICE 1. In which series are the elements listed in order of increasing electronegativity? Cl < S < P As < S < F C< Si < Ge N < P < Br ANS: C Chapter 2 11 Polar Covalent Bonds: Acids and Bases 2. Based on electronegativity values, in which of the following is the bond, represented by —, the most polar? H3C—I H3C—Cl H3C—Na H3C—OH ANS: B 3. Which of the following substances has a zero dipole moment? CO2 Cl2C=CCl2 HOCH2CH2OH HCl2CCHCl2 All have zero dipole moments. ANS: E 4. The following shows a gray-scale image of an electrostatic potential map with the atoms labeled. Which of the numbered regions would appear reddest in a color image? 1 2 3 4 1, 2, and 3 would be the same shade of red. 2, 3, and 4 would be the same shade of red. ANS: D 5. How many resonance forms can be drawn for the NO3– ion? 1 2 3 4 None, the nitrate ion does not exhibit resonance. ANS: C 12 6. Which of the following would represent the strongest acid? ANS: D 7. Which of the following substances would be expected to have the largest pKa? ANS: A Chapter 2 8. Which of the following does not characterize the curved arrow formalism? The arrow shows the movement of electrons not atoms. The atom at the head of the arrow is the electron pair acceptor. The atom at the tail of the arrow is a Lewis acid. The species containing the atom at the head of the arrow will have the smaller pKa. All of these correctly describe the curved arrow formalism. ANS: C 9. Which of the following substances would exhibit hydrogen bonding a, b, and c All would exhibit hydrogen bonding. ANS: E 13 Polar Covalent Bonds: Acids and Bases 10. The structure for Vitamin K which is involved in blood clotting is shown below. This vitamin would be: classified as hydrophilic. fat-soluble. water-soluble. both hydrophilic and hydrophobic. ANS: C 11. The following is generic depiction of a reaction using the curve arrow formalism. Which of these statements is not correct for this reaction? Electrons move from C to B. Electrons move from B to A. In the products, a bond forms between C and B. In the products, A would have a positive charge. ANS: D 14 Chapter 3—Organic Compounds: Alkanes and Their Stereochemistry SHORT ANSWER Exhibit 3-1 MATCH a structure below to each of the following descriptions and place the letter corresponding to the structure in the blank. 1. _____ is an amino aldehyde. ANS: B 2. _____ is an aromatic ketone. ANS: E 3. _____ is a tertiary chloride. ANS: C 4. _____ is a cyclic alkane with two cis methyl groups. ANS: C 1 Organic Compounds: Alkanes and Their Stereochemistry 5. Circle and name each functional group in the following structure. ANS: Exhibit 3-2 Label the indicated atoms in the structure below as 1, 2, 3, or 4. 6. Refer to Exhibit 3-2. The atom at A is _____. ANS: 4 2 7. Refer to Exhibit 3-2. The atom at B is _____. ANS: 2 8. Refer to Exhibit 3-2. The atom at C is _____. ANS: 3 9. Refer to Exhibit 3-2. The atom at D is _____. ANS: 1 Exhibit 3-3 Label the following pairs of compounds as: identical constitutional isomers neither Place the letter of the correct answer in the blank. 10. _____ ANS: b 11. _____ ANS: c Chapter 3 3 Organic Compounds: Alkanes and Their Stereochemistry 12. _____ ANS: a IUPAC Naming Instructions: Provide proper IUPAC names. 13. Name: (CH3)2CHCH2CH2CH(CH2CH3)CH2C(CH3)3 ANS: 4-ethyl-2,2,7-trimethyloctane 14. Name: ANS: 7-bromo-3-ethyl-2,2,5,5-tetramethyloctane or 2-bromo-6-tert-butyl-4,4-dimethyloctane 15. Name: ANS: 5-isopropyl-3-methyloctane 4 16. Name: ANS: 5-ethyl-3,4-dimethyloctane Drawing Instructions: Draw skeletal structures corresponding to each of the given names. 17. Draw: 6-ethyl-4-isopropyldecane ANS: 18. Draw: 2-fluoro-3-methylpentane ANS: 19. Draw: 4-(2,2-dibromoethyl)-3,5-dichloroheptane ANS: Chapter 3 Exhibit 3-4 Experiments have shown that for 1,2-dichloroethane, ClCH2CH2Cl, in carbon tetrachloride solution at 25 °C, 70% of the molecules are in the anti and 30% are in the gauche conformation. 20. Refer to Exhibit 3-4. Draw a Newman projection of the anti conformation of 1,2-dichloroethane. 5 Organic Compounds: Alkanes and Their Stereochemistry ANS: 21. Refer to Exhibit 3-4. Draw a Newman projection of the gauche conformation of 1,2-dichloroethane. Explain why the majority of the molecules are not in the gauche conformation. ANS: The gauche conformation is a higher energy state than the anti conformation due to the torsional strain caused by the close proximity of the two chlorine atoms. Exhibit 3-5 Cipro (Ciprofloxacin) is a synthetic broad spectrum antibacterial agent. It was most recently in the news as the antibiotic of choice for the treatment of anthrax. The structure of Cipro is shown below. 6 22. Refer to Exhibit 3-5. Circle the functional groups in the Cipro representation above. ANS: Exhibit 3-6 Predict the hybridization of the indicated atoms in Cipro. 23. Refer to Exhibit 3-6. The hybridization of this nitrogen atom (A) is __________. ANS: sp3 24. Refer to Exhibit 3-6. The hybridization of this carbon atom (B) is __________. ANS: sp2 25. Refer to Exhibit 3-6. The hybridization of this carbon atom (C) is __________. ANS: sp3 Chapter 3 7 Organic Compounds: Alkanes and Their Stereochemistry 26. Put a box around the most polar bond in Cipro based on electronegativity values. ANS: 27. Name the following hydrocarbon. ANS: 2,3-dimethylbutane Sight along the C2-C3 bond of 2-methylbutane. 28. How many eclipsed conformations can be drawn? ANS: 3 8 29. Draw the staggered conformations. ANS: 30. Arrange the following conformation from lowest to highest energy. ANS: Chapter 3 31. Explain your energy order from lowest to highest. ANS: The lowest energy conformation of those shown is the one staggered conformation. Of the two eclipsed conformations given, the one in which there is one eclipsed interaction (energy cost: 11 kJ/mol) and one eclipsed interaction (energy cost: 6.0 kJ/mol) and one eclipsed interaction(energy cost: 4 kJ/mol, for a total energy cost of 11 kJ/mol + 6 kJ/mol + 4 kJ/mol = 21 kJ/mol) will be higher than the one in which there are three eclipsed interactions (energy cost: 6.0 kJ/mol x 3 = 18 kJ/mol). 9 Organic Compounds: Alkanes and Their Stereochemistry 32. Draw at least four isomers with molecular formula given below. C4H10O ANS: There are seven total isomers, four alcohols and three ethers. MULTIPLE CHOICE 1. Which of the following functional groups if bonded to a three-carbon chain would have the largest – charge? alcohol phosphate ether sulfide ANS: C