PRACTICE PROBLEMS, CHAPTERS 1-3

Transcription

1 PRATIE PRBLEMS, APTERS 1-3 (overed from h. 3: Alkane and Alkyl alide nomenclature only) 1. The atomic number of boron is 5. The correct electronic configuration of boron is: A. 1s 2 2s 3 B. 1s 2 2p 3. 1s 2 2s 2 2p 1 D. 2s 2 2p 3 E. 1s 2 2s 2 3s 1 2. ow many distinct p orbitals exist in the second electron shell, where n = 2? 3. An oxygen atom has valence electrons. 4. Draw a correct Lewis structure for boric acid, B()3. 5. Draw a correct Lewis structure for t-butanol, (3)3. 6. Draw a correct Lewis structure for acetonitrile, The formal charge on nitrogen in the compound below is Which of the following are correct Lewis structures for nitric acid, 3? A B 9. The formal charge on oxygen in dimethyl ether, 33, is. 10. Which of the following choices represent(s) a pair of resonance forms? 3 and and 3 3 A B and

2 11. Draw an acceptable line-angle formula for the molecule shown rbitals which are equal in energy are referred to as. A. degenerate B. polar. nodes D. filled E. nonpolar 13. When filling two or more orbitals of the same energy with electrons, the electrons will go into different orbitals rather than pair up in the same orbital. True False 14. ne or more of the atoms in the structure shown should have nonzero formal charges. Redraw the structure and indicate any such charges. P 15. ne or more of the atoms in the structure shown should have nonzero formal charges. Redraw the structure and indicate any such charges. B 16. When a molecule can best be represented as a series of resonance forms, each of these forms always contributes to the same degree in the hybrid. True False 17. The tells us that each orbital can hold a maximum of 2 electrons. A. Aufbau principle B. Pauli exclusion principle. und's rule principle D. Lehatelier principle E. Uncertainty principle 18. Draw a line-angle formula for ( 3 ) In the compound sodium methoxide (a 3 ), there is bonding. A. ionic B. polar covalent. nonpolar covalent D. a mixture of ionic and covalent E. resonance stabilized

3 20. A carbon-hydrogen bond in ethane ( 3 3 ) is best described as. A. highly polar B. essentially nonpolar. ionic D. a multiple bond E. resonance stabilized 21. What kind of orbitals result when orbitals of different atoms interact? 22. What kind of molecular orbital (sigma or pi) results when the two atomic orbitals shown below approach each other head to head as indicated? 23. What kind of molecular orbital (sigma or pi) results when the two atomic orbitals shown below approach each other sideways as indicated? 24. Which of the following statements about pi molecular orbitals is/are correct? A. They are cylindrical. B. Most of their electron density is centered above and below the internuclear axis.. When two atoms are connected by a double bond, both of those bonds are pi bonds. D. Both B and. E. A, B, and. 25. The bond angle in hydrogen cyanide () is degrees. 26. The bond angle in propane is degrees. 27. The bond angle in acetone (33) is degrees. 28. In boron trifluoride (BF3) the boron atom is hybridized and the FBF bond angle is degrees. 29. In triethylamine [(32)3] the atom is hybridized and the geometry of the atom is. 30. Structures which differ only in rotations about a single bond are called. A. Structural isomers B. Geometric isomers. onformers D. Resonance structures 31. What is the hybridization of the oxygen atom in 3? 32. What is the hybridization of the ntrogen atom in ( 3 ) 2? 33. ow many pi bonds are present in the following molecule?

4 34. Which of the molecules below can be properly called an ether? A. 32(3)2 B D. 33 E Which of the molecules below has the higher boiling point? Briefly explain your choice. 322 or Which of the molecules below has the higher boiling point? Briefly explain your choice. (3)3 or Which compound is more soluble in water? Briefly explain your choice. 33 or Which compound is more soluble in water? Briefly explain your choice. (3)2 or Are the two compounds shown best described as geometric isomers, structural isomers, or not isomeric? l l l Br Br l 40. Are the two compounds shown best described as geometric isomers, structural isomers, or not isomeric? Are the two compounds shown best described as geometric isomers, structural isomers, or not isomeric? Are the two compounds shown best described as geometric isomers, structural isomers, or not isomeric? 43. Are the two compounds shown best described as geometric isomers, structural isomers, or not isomeric?

5 44. Are the two compounds shown best described as geometric isomers, structural isomers, or not isomeric? 45. Which one of the molecules shown below has no net molecular dipole moment? A. 3l B. 2=2. 2 D. 2l2 E hoose the term below which best describes the geometry of acetylene (). A. trigonal bipyramidal B. trigonal. tetrahedral D. square planar E. linear 47. Which of the functional groups below contain a hydroxyl group as a part of their structure? A. aldehyde B. alcohol. carboxylic acid D. amine E. B and 48. What is the name of the functional group found in the molecule 32? 49. ow many sigma bonds and how many pi bonds are present in the molecule shown? 50. ow many sigma bonds and how many pi bonds are present in acrylonitrile, 2 =? 51. Which of the following statements concerning the cyclic molecule shown is not true? A. It contains a pi molecular orbital formed by the overlap of a carbon p orbital with an oxygen p orbital. B. It contains a sigma molecular orbital formed by the overlap of two carbon sp 2 orbitals.. It contains a sigma molecular orbital formed by the overlap of two carbon sp 3 orbitals. D. It contains a pi molecular orbital formed by the overlap of two carbon p orbitals. E. It contains a sigma molecular orbital formed by the overlap of a carbon p orbital with an oxygen sp 3 orbital. 52. Give structures for the 3 isomers with molecular formula 512 and provide the common name of each. 53. Provide an acceptable IUPA name for the alkane shown below.

6 54. Provide an acceptable IUPA name for the alkane shown below. 55. Provide an acceptable IUPA name for the alkane shown below. ( 3 ) 2 3 ( 2 ) Provide an acceptable IUPA name for the alkane shown below. 57. Draw an acceptable structure for 4-ethyl-6-(1,2-dimethylpropyl)decane. 58. Draw an acceptable structure for 3-ethyl-3-methylhexane. 59. Draw an acceptable structure for 6-ethyl-2,6,7-trimethyl-5-propylnonane. 60. Give the IUPA name for the cycloalkane shown below Provide an acceptable name for the compound shown below. 3 Br Provide an acceptable IUPA name for ( 3 ) 2 I. 63. Provide an acceptable IUPA name for the compound shown below. l l 64. Provide the structure of isopropyl iodide. 65. Provide the structure of 1-bromo-3-methylhexane.

7 66. Which of the following is a secondary alkyl halide? A. methyl bromide B. isopropyl chloride. t-butyl iodide D. propyl bromide E. isobutyl chloride 67. Which of the following is a primary alkyl halide? A. methyl bromide B. isopropyl bromide. t-butyl iodide D. cyclohexyl bromide E. isobutyl chloride

8 1. 2. Three: 2p x, 2p y, 2p z 3. Six ASWERS 4. B or B 9. Zero 10. B and only. Atoms have been moved in A, which is not allowed. 11. or A 13. TRUE 14. P 15. B

9 16. False 17. B D 20. B 21. Molecular orbitals 22. Sigma 23. Pi 24. B degrees degrees degrees 28. sp 2 / sp 3 /tetrahedral sp sp 33. Six. The triple bond contains two of them. 34. B 35. The alcohol, 322, has the higher boiling point, since it is capable of intermolecular hydrogen bonding. The ether is not has the higher boiling point, since it is capable of intermolecular hydrogen bonding. 37. The alcohol, 32, is more soluble in water since it can form a hydrogen bond to water and accept a hydrogen bond from water. The ether, 33, can only accept a hydrogen bond from water. 38. The amine, (3)2, is more soluble in water since it can hydrogen bond with water. Alkanes are not capable of hydrogen bonding with water. 39. Structural isomers: same molecular formulas, but different atom connectivities. 40. Structural isomers 41. Geometric (cis-trans) isomers: They owe their existence to hindered rotation around the pi-bond. 42. Structural isomers 43. Structural isomers 44. Geometric (cis-trans) isomers: Represents a carbon atom attached to the = bond is relationship Trans relationship 45. B 46. E 47. E 48. arboxilic acid: sigma bonds and 3 pi bonds. You must count every - and - bond. The bond is a triple bond, which alone accounts for two pi and one sigma bond.

10 50. 6 sigma bonds and 3 pi bonds. 51. E. There is no sp 3 oxygen in the molecule. 52. pentane, or n-pentane isopentane neopentane 53. 2,5-dimethylheptane ,2-dimethyl-5-(1-methylpropyl)nonane (1) (2) (3) (1-methylethyl)decane ( 3 ) 2 3 ( 2 ) ethyl-7-methyl-5-propylnonane (1) (2)

11 trans-1-ethyl-2-methylcyclopentane bromo-4,4-dimethylcyclohexane iodo-2-methylpentane 63. cis-1, 2-dichlorocyclopentane 64. ( 3 ) 2 -I (3)22Br 66. B (Isoproyl chloride). hlorine is attached to a secondary carbon. l 67. E (Isobutyl chloride). hlorine is attached to a primary carbon: l