1. Identify the missing particle in the following equation: U 4 2 He +? A)

Transcription

1 Chem 101B Study Questions Chapters 19,21,22 Review Thursday 5/4/2017 Final Exam 12:30 p.m., Tuesday 5/9/2017 Not collected for credit. 1. Identify the missing particle in the following equation: U 4 2 He +? A) Th B) U C) Pu D) Th 2. An unstable isotope of rhenium, 191 Re, has a half-life of 9.8 minutes and is a beta producer. What is the other product of the reaction? A) 191 W B) 192 Pt C) 190 Os D) 191 Os E) 190 W 3. It is desired to determine the concentration of arsenic in a lake sediment sample by means of neutron activation analysis. The nuclide As captures a neutron to form As, which in turn undergoes decay. The daughter nuclide produces the characteristic rays used for the analysis. What is the daughter nuclide? A) B) C) D) E) Page 1

2 4. Electron capture transforms K into what nuclide? 40 A) 19 K 39 B) Ca C) Ca D) Ar 18 4 E) He 2 5. If Pb undergoes a beta decay and the product of this decay undergoes another beta decay, which nuclide is produced? 214 A) Pb B) Pb C) Bi D) Po E) Bi In the following fission reaction, identify the other product: 235 U + 1 n 139 I n A) Zr B) Mo C) Mo D) Y E) Y Iron-56 is a stable nuclide. What is the most likely decay for the iron-59 isotope? A) -ray emission B) decay C) two of these D) decay E) positron emission Page 2

3 8. Nuclides with too many neutrons to be in the band of stability are most likely to decay by what mode? A) beta emission B) positron production C) alpha emission D) fission E) electron capture Use the following to answer questions 9-10: The U-238 nucleus decays to form Pb-206 by and decays. 9. Calculate the number of decays. A) 6 B) 8 C) 4 D) Calculate the number of decays. A) 4 B) 8 C) 2 D) The rate constant for the beta decay of thorium-234 is / day. What is the half-life of this nuclide? A) days B) days C) days D) days E) days Page 3

4 12. The number of a certain radioactive nuclide present in a sample decays from 160. to 20. in 40 minutes. What is the half-life of this radioactive species? A) 28 minutes B) 8 minutes C) 23 minutes D) 13 minutes E) 18 minutes 13. The number of half-lives needed for a radioactive element to decay to about 6% of its original activity is (choose nearest number): A) 3 B) 4 C) 6 D) 2 E) The I-131 nuclide has a half-life of 8.0 days. If you originally have a 1.8-kg sample, after 1.0 months you will have approximately A) 201 g B) 134 g C) 149 g D) less than 1 g E) 268 g 15. If more than one neutron from each fission event causes another fission event, the fission situation is described as A) supercritical B) moderated C) subcritical D) critical 16. What component of a nuclear reactor moderates the rate of the reaction? A) cyclotron B) steam turbine C) control rods D) cooling water E) containment shell Page 4

5 17. The greatest radiation exposure for Americans comes from which of the following? A) electrical transmission wires B) a combination of the natural causes of radiation including cosmic rays C) nuclear power plants D) medical x-rays E) industrial waste 18. Which type of radiation has the lowest penetrating ability? A) beta particle B) alpha particle C) positron D) gamma ray E) more than one of these 19. Which of the following is a d 7 ion (contains 7 d electrons)? A) Mn(IV) B) Co(II) C) Cu(II) D) Mn(II) E) At least two of the above (a-d) are d 7 ions. 20. What is the electron configuration of the Mn(II) ion? A) [Ar] 3d 5 B) [Ar] 4s 2 3d 5 C) [Ar] 4s 1 3d 5 D) [Ar] 4s 2 3d The electron configuration for Cr 2+ is A) [Ar] 4s 1 3d 5 B) [Ar] 3d 4 C) [Ar] 4s 2 3d 2 D) [Ar] 4s 2 3d 4 Page 5

6 22. A complex ion is a charged species consisting of a metal ion surrounded by A) ligands B) ligands and counter ions C) hydrogen ions D) other transition metals 23. Which of the following is true? A) The third ionization energy for Zn is significantly lower than that of Sc. B) The first ionization energy for Zn is significantly higher than that of Sc. C) The first ionization energy for Zn is significantly lower than that of Sc. D) The third ionization energy for Zn is significantly higher than that of Sc. E) Two of these are correct. 24. The metals with the highest ionization energies are most likely to be found in nature in the elemental state. A) True B) False 25. An element that is a significant component of both brass and bronze is: A) iron B) copper C) nickel D) zinc E) tin 26. Which of the following complexes can exhibit optical isomerism? (en = H2N CH2 CH2 NH2 and is a bidentate ligand) A) Co(NH3)3Cl3 B) cis Co(en)2Cl2 C) cis Co(NH3)4Cl2 D) trans Co(en)2Br2 27. Which of the following complexes shows geometrical isomerism? A) [Co(NH3)5Cl]Cl2 B) [Co(NH3)5Cl]SO4 C) K[Co(NH3)2Cl4] D) [Co(NH3)6]Cl3 Page 6

7 28. Which complex ion shape is not capable of showing cis trans isomerism? A) square planar B) tetrahedral C) octahedral D) two of these 29. Which of the following is true about coordination complexes? A) Only complexes with coordination number six are found in nature. B) When the ligands approach a transition metal ion in an octahedral field, the dxz, dyz, and dxy atomic orbitals are affected the least by the ligands. C) The metal is a Lewis base and the ligands are Lewis acids. D) None of the above is true. E) All of the above are true. Use the following to answer questions 30-31: Specify the number of unpaired electrons. 30. CuCl2 (linear) A) 5 B) 2 C) 4 D) 0 E) NiCl4 2 (tetrahedral) A) 5 B) 0 C) 1 D) 2 E) 4 Page 7

8 32. Which of the following crystal field diagrams is correct for Co(CN)6 4 where CN is a strong field ligand? A) B) C) D) 33. True or False? The complexes of Zn 2+ are all diamagnetic. A) True B) False Use the following to answer questions 34-35: How many unpaired electrons are found in each of the following complex ions? 34. NiCl [Ni(CN)6] The color of a transition metal complex results from: A) transition of an electron between d orbitals B) bending vibrations C) transition of an electron between an s and a p orbital D) nuclear magnetic resonance E) stretching vibrations Page 8

9 37. Name the following: CH 3 CH 3 CH 2 CCH 3 CH 2 CH 3 A) 2-methyl-2-ethylbutane B) 2,2-diethylpropane C) n-heptane D) 3,3-dimethylpentane 38. How many isomers of C3H8 are there? A) 6 B) 3 C) 5 D) 1 E) In lecture, the professor named a molecule 4-ethylpentane. An alert student pointed out that although the correct structure could be drawn, the name did not follow systematic rules. What is the correct systematic name for the molecule? A) 3-methylhexane B) 4-methylhexane C) 1-methyl-1-propylpropane D) 2-ethylpentane 40. Hydrocarbons containing a carbon carbon triple bond are called A) alkanes B) alkynes C) aldehydes D) alkenes E) cyclic alkanes Page 9

10 41. Name the following: CH 3 CH 2 CH 3 C C C H H A) 2-ethyl-3-butyne B) 1-hexyne C) 3-methyl-1-pentyne D) 3-methyl-4-pentyne E) 2-ethynyl butane 42. Name the following: Cl CH 3 H 3 C Cl A) 2,3-dichloro-trans-2-butene B) 1-chloro-1-methyl-2-chloro-propene C) 2,3-dichloro-cis-2-butene D) 2,3-dichloro-1-methyl-propene E) 2-chloro-3-chloro-cis-2-butene 43. Name the following: CH3 (CH2)4 CH3 A) butane B) pentane C) heptane D) ethane E) hexane Page 10

11 44. Which of the following compounds can exhibit geometric isomerism? A) Cl H C C B) C) D) E) Cl H H 3 C CH 3 C C H 3 C CH 2 Cl Br H C C Cl H H H C C Cl Cl H H H C C H Cl Cl 45. What is the compound represented by the following structure? A) benzene, C6H6 B) cyclohexatriene, C6H12 C) cyclohexene, C6H10 D) cyclohexatriene, C6H9 E) cyclohexane, C6H The boiling point of methanol is much higher than that of ethane. This is primarily due to A) the significant molecular size difference between methanol and ethane B) the carbon oxygen double bond in the methanol C) the hydrogen bonding in methanol D) the difference in molar masses of methanol and ethane Page 11

12 47. Classify the following molecule: CH 3 H H A) tertiary alcohol B) primary alcohol C) phenol D) secondary alcohol E) ether H 3 C C C CH 2 CH 3 O H 48. Which molecule is an ether? A) CH3CH2NH2 B) O CH 3 CH 2 COCH 3 C) CH3CH2OCH3 D) O CH 3 CH 2 CCH Identify the type of organic compound shown: H 3 C C CH 2 CH 3 A) ester B) amine C) alcohol D) aldehyde O Page 12

13 50. Identify the type of organic compound shown: H H H C C C O H H H A) ester B) amine C) ketone D) aldehyde 51. What organic compounds often have pleasant fruity odors? A) carboxylic acids B) ethers C) amines D) alkynes E) esters 52. Referring to the structures below, which statement is true? I. O H C O CH 2 CH 2 OH II. O HOCH 2 CH 2 C OH III. O HOCH 2 CH 2 O C H A) I and III are structural isomers of each other. B) II and III are different conformations of the same compound. C) I and II have different molecular formulas. D) I and III are the same compound. E) II and III are stereoisomers of each other. 53. Which molecule is an ester? A) CH3CH2NH2 B) O CH 3 CH 2 COCH 3 C) CH3CH2OCH3 D) O CH 3 CH 2 CCH 3 Page 13

14 54. Which of the following functional groups does not contain a doubly bonded oxygen (C=O)? A) Carboxylic acid. B) Aldehyde. C) All contain a C=O double bond. D) Ketone. E) Carboxyl. 55. Identify the type of organic compound shown: (CH3)3N A) ester B) ketone C) aldehyde D) amine 56. Why does octane have a higher boiling point than ethane, 126 C versus 89 C? A) Octane has stronger London dispersion forces than ethane. B) Octane exhibits hydrogen bonding and ethane does not. C) Octane has a higher vapor pressure than ethane. D) Octane contains more double bonds than ethane. E) At least two of the above are correct Consider a certain type of nucleus that has a half-life of 32 min. Calculate the percent of original sample of nuclides remaining after 2.6 hours have passed. 58. The half-life of 90 Sr is 28 years. How long will it take for a given sample of 90 Sr to be 83 % decomposed? 59. The rate constant for the decay of 45 Ca is / day. What is the half-life of 45 Ca? The half-life of a sample has been defined as the time it takes for half of a sample to decay. The fifth-life can be defined as the time it takes for one-fifth of a sample to decay. Given these definitions, calculate the fifth-life of a sample that has a half-life of 28 years. (hint: consider fifth life means that N = 0.8No) Page 14

15 61. The half-life for electron capture for K is years. What percent of the original K remains after years? 62. Calculate the change in energy released (kj/mol) for the decay of Radium-226 given the following data: 226 Ra 4 He Rn g/mol g/mol g/mol 63. Iron-56 ( Fe) has a binding energy per nucleon of 8.79 MeV. (1MeV is J). Determine the difference in mass between one mole of iron-56 nuclei and the component nucleons of which it is made. 64. Calculate the binding energy of a Ni-60 atom (in MeV/nucleon). 1 amu = kg 1 MeV = J mass 60 Ni atom = amu mass proton = amu mass neutron = amu 65. Which of the following compounds exhibit geometric isomers? I. Pt(NH 3 ) 2 Cl 2 (square planar) II. [Co(H 2 O) 2 ]Cl 3 III. Ni(NH 3 ) 4 (NO 2 ) 2 IV. K 2 [CoCl 4 ] 66. Explain why copper(i) complexes would be expected to be colorless. 67. Fluoride ion ranks low in the spectrochemical series and produces a weak crystal field in complex ions. Based on this information, predict the number of unpaired electrons in CoF A d 6 ion (Fe 2+ ) is complexed with six strong-field ligands (for example, SCN ). What is the number of unpaired electrons in this complex? Page 15

16 69. The complex ion NiCl4 2 is tetrahedral. The number of unpaired electrons in the complex is: Use the following to answer questions 70-71: Draw the orbital-splitting diagram for the species below. 70. [Fe(H2O)6] 3+ (assume weak field) 71. K4Mn(CN)6 (assume strong field) 72. Name the compound with carbon skeleton (minus any hydrogen atoms) below: C C C C C C C C C C C C C 73. Name the following compound: H H H H C C C H H OH H 74. Provide and name three (3) isomers of hexane. 75. What is the product of the following reaction? CH3CH=CHCH2CH3 + Cl2?? 76. Provide the structure of 3-methyl-1-butanol. 77. Provide the structure of trans-2-hexene. 78. Provide the structure of 4-decyne. Page 16

17 Answer Key 1. A 2. D 3. A 4. D 5. D 6. E 7. B 8. A 9. B 10. D 11. E 12. D 13. B 14. B 15. A 16. C 17. B 18. B 19. B 20. A 21. B 22. A 23. D 24. A 25. B 26. B 27. C 28. B 29. B 30. D 31. D 32. C 33. A A 37. D 38. D 39. A 40. B 41. C 42. A 43. E Page 17

18 44. D 45. A 46. C 47. A 48. C 49. E 50. D 51. E 52. D 53. B 54. C 55. D 56. A % years days years % kj/mol kg 64. mass defect = amu mass defect = e 28 kg binding energy = e 11 J/ 60 Ni or MeV binding energy per nucleon = MeV/nucleon 65. I, III exhibit geometric isomers. Others do not: II--Linear can't do this IV--since Cl ligands are all the same 66. Copper (I) has lost 1 valence electron, so the d-electron configuration is d 10. Even in a crystal field, there would be no vacant higher energy d orbitals for an electron to absorb a photon. Thus no visible wavelengths of light would absorbed E E ethyl-2,5,6-trimethyloctane propanol (common name: isopropyl alcohol) Page 18

19 74. There are 5 total isomers of hexane: hexane, CH3(CH2)4CH3 2-methylpentane, (CH3)2CHCH2CH2CH3 3-methylpentane, (CH3CH2)2CHCH3 2,3-dimethylbutane, (CH3)2CHCH(CH3)2 2,2-dimethylbutane, (CH3)3CCH2CH3 75. CH3CHClCHClCH2CH3 76. (CH3)2CHCH2CH2OH or Page 19