UNIVERSITY OF VICTORIA FINAL EXAMINATION, DECEMBER 2015 CHEMISTRY 101 Fundamentals of Chemistry I

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1 UNIVERSITY OF VICTORIA FINAL EXAMINATION, DECEMBER 2015 CHEMISTRY 101 Fundamentals of Chemistry I Instructors: A01 CRN Dr. S. Briggs; A02 CRN & A03 CRN Dr. S. McIndoe Before you begin to write your exam you should find three items on your exam desk: 1) An exam placemat bearing your name and student ID number. Sign this page. It will be collected during the exam when we check your student ID card. Do not use this page for scrap paper. 2) This exam question paper, containing an unstapled DATA sheet inside the cover page. 3) A bubble sheet (UVic new format blue form) for recording your answers. Complete the information section of the bubble sheet according to the template below. Hand in only the bubble sheet at the end of the exam period (3 hours). This exam question paper has 15 pages plus an unstapled DATA sheet. Students must count the number of pages in this examination paper before starting to write the exam. Report any discrepancy immediately to one of the instructors in the room. This exam consists entirely of multiple choice questions. There are 66 multiple choice questions. This question paper contains enough blank space for working out the questions. No other paper is permitted. The basic Sharp EL510 calculator and the Sharp EL-510 RNB are the only ones approved for use in Chemistry 101. It is a University Calendar regulation that no student may arrive at the exam after the first half hour and no student may leave the exam in the first half hour. If you finish your exam before 2¾ hours have elapsed then you may hand in your bubble sheet and leave. We ask that students not leave (i.e. that students remain seated) during the last 15 minutes of the exam so that everyone remaining may finish their exams without noise or disturbance. DO NOT BEGIN UNTIL TOLD TO DO SO BY THE INVIGILATOR

2 Chemistry 101 Final Examination Dec. 16, 2015; Page 2 of 15 The answers must be coded on the optical sense form (bubble sheet) using a pen or soft pencil. Select the best response for each question below. To the right is the energy level diagram for an electron in a hydrogen atom (not to scale). Answer questions 1 to 4 with reference to this diagram. 1. Which transition represents the ionization of the hydrogen atom? A. R B. S C. V D. Y E. Z 2. Which transition(s) emit a visible photon ( nm)? A. R B. T, U, & X C. R & Z D. R, T, U, W, X, & Z E. S 3. Which transition(s) emit photons with an energy greater than J? A. R B. S C. T, U, & X D. R, T, U, W, X, & Z E. R & Z 4. Which transition can be caused by absorption of an infrared photon? A. R B. S C. V D. W E. Y

3 Chemistry 101 Final Examination Dec. 16, 2015; Page 3 of A krypton (Kr) atom has how many electrons with the quantum numbers n = 3, l = 2? A. 2 B. 6 C. 10 D. 18 E A gold (Au) atom has how many electrons with the quantum numbers n = 4, m l = -3? A. 2 B. 6 C. 10 D. 18 E The electrons used in electron microscopy have a velocity of 70% of the speed of light. What is their wavelength in nm? A B C D E A heated sample of an element emits only some frequencies of light and not others. This is because: A. Electrons orbit nuclei in circular orbits, and only orbits of certain radii are allowed. B. Electrons are excited to higher energy levels and emit light in the process. C. Electrons excited by the heat energy emit light when falling to lower energy levels, and only certain energy levels are allowed. D. The nature of the measuring instrument causes lines to appear. E. The Uncertainty Principle says we cannot know about the in-between frequencies. 9. Identify the ion that has the following electron configuration. 1s 2 2s 2 2p 6 3s 2 3p 6 3d 9 A. Co + B. Cu + C. Cu 2+ D. Ni 2+ E. Zn 2+

4 Chemistry 101 Final Examination Dec. 16, 2015; Page 4 of Which of the orbitals below is NOT a d orbital? 11. The electron configuration for a ground state Fe 2+ ion is: A. [Ar] 3d 6 4s 2 B. [Ar] 3d 8 C. [Ar] 3d 6 D. [Ar] 3d 5 4s 1 E. [Ar] 3d 4 4s Which element from the ones shown below has the highest first ionization energy (I 1 )? A. Cs B. Zr C. Mn D. P E. Cl 13. Which element from the ones shown below has the highest second ionization energy (I 2 )? A. Ar B. Cl C. P D. Al E. Mg 14. Why is the electron affinity of P less negative than either Si or S? That is, why is adding an electron to a neutral phosphorus (P) atom less exothermic (less favourable) than adding an electron to a silicon or sulfur atom? A. P has a lower Z eff than both Si and S. B. P has a higher Z eff than both Si and S. C. Adding an electron to an already-occupied s orbital is energetically unfavourable. D. Adding an electron to an already-occupied p orbital is energetically unfavourable. E. P starts with an odd number of electrons, but both Si and S have an even number. 15. Which electron configuration is INCORRECT for the ground state atom listed? A. Na = [Ne] 3s 1 B. Ga = [Ar] 4s 2 3d 10 5p 1 C. Sb = [Kr] 5s 2 4d 10 5p 3 D. Pm = [Xe] 6s 2 4f 5 E. Lu = [Xe] 6s 2 4f 14 5d 1

5 Chemistry 101 Final Examination Dec. 16, 2015; Page 5 of Given the following bond distances, estimate the bond length (in pm) in the molecule X-Y. A. 100 B. 120 C. 150 D. 160 E Which of the following dipole moment vectors best reflects the molecular polarity of SiF 4? 18. Which one of the following ions has nonbonding valence electrons at the central atom? A. SiF 6 2 B. GeCl 5 C. CO 3 2 D. SF 3 + E. ClO Which of these AB 4 molecular geometries is observed for XeF 4?

6 Chemistry 101 Final Examination Dec. 16, 2015; Page 6 of 15 Questions concern the molecule acrylonitrile, C 3 H 3 N (structure shown to the right). 20. How many nonbonding valence electrons are there in a molecule of acrylonitrile? A. 0 B. 2 C. 4 D. 6 E The H-C-C and C-C-C bond angles in a molecule of acrylonitrile are closest to what pair of values respectively? A , B. 120, 120 C , 120 D. 120, E. 120, How many sp hybrid orbitals are there in a molecule of acrylonitrile? A. 1 B. 2 C. 3 D. 4 E How many sp 2 hybrid orbitals are there in a molecule of acrylonitrile? A. 2 B. 4 C. 6 D. 8 E A molecule of acrylonitrile has how many sigma (σ) and how many pi (π) bonds? A. 4 σ, 5 π B. 6 σ, 2 π C. 6 σ, 3 π D. 7 σ, 1 π E. 7 σ, 2 π 25. Acrylonitrile contains how many unhybridized p orbitals? A. 2 B. 3 C. 4 D. 5 E Acrylonitrile contains what type of functional group? A. alkane B. alkene C. alkyne D. aldehyde E. amide

7 Chemistry 101 Final Examination Dec. 16, 2015; Page 7 of Acrylonitrile has a higher boiling point (77 C) than butane (0 C) despite a slightly lower molecular weight, due mainly to what type of intermolecular force? A. ionic bonding B. ion-dipole C. dipoledipole D. hydrogen bonding E. London dispersion 28. Polyacrylonitrile forms from acrylonitrile in a reaction called? A. combustion B. condensation polymerization C. addition polymerization D. crystallization E. solidification 29. There are 5 different (isomeric) alkanes with the formula C 6 H 14. Which one has the highest boiling point? A. hexane B. 2-methylpentane C. 3-methylpentane D. 2,3-dimethylbutane E. 2,2-dimethylbutane 30. Which of the following alkanes does NOT have the molecular formula C 7 H 16? A. cycloheptane B. 2-methylhexane C. 3-ethylpentane D. 2,2,3-trimethylbutane E. 2,4-dimethylpentane 31. Inspect the following incomplete resonance structures, and identify the INCORRECT statement about the nitrous oxide molecule. A. The molecule is linear. B. The N-N bond is shorter than the N-O bond. C. The right-hand structure has a greater weighting (is more important) than the left-hand one. D. The central nitrogen atom is sp hybridized. E. There is another possible Lewis structure for this molecule, but it is less important than either of the two shown

8 Chemistry 101 Final Examination Dec. 16, 2015; Page 8 of Consider the molecules OCO, SCS, OCS, NNO and NNS, which all have the same number of valence electrons. (The atoms are connected in the order given.) How many of these molecules are non-polar? A. 1 B. 2 C. 3 D. 4 E The bond order in SO 3 2 is A. 1 B C. 1.5 D E The bond order in He 2 2+ is A. 0 B C. 0.5 D E Combustion of methane, CH 4, produces water and carbon dioxide according to the following reaction. CH 4 (g) + 2O 2 (g) CO 2 (g) + 2H 2 O (g) Using bond energies, estimate the energy change for this reaction in kj mol -1. A B C D E. 108

9 Chemistry 101 Final Examination Dec. 16, 2015; Page 9 of 15 Questions refer to the figures below. All of these structures have five (5) electron domains. 36. Which of these molecular shapes best represents the shape of the molecule SeF 4? 37. Which of the shapes above can lead to a molecule with an overall dipole moment vector of 0 (i.e. a nonpolar molecule)? A. A only B. E only C. A and E D. B, C and D E. None of them 38. Which element M will lead to an MF 3 molecule with shape D above? A. Ga B. Ge C. As D. Se E. Br 39. Which of the following compounds of xenon has exactly one nonbonding pair of electrons on the xenon atom? A. XeF 2 B. XeF 4 C. XeOF 4 only D. XeO 3 only E. XeOF 4 and XeO 3

10 Chemistry 101 Final Examination Dec. 16, 2015; Page 10 of Which phase is missing from the figure below? A. Chlolesteric liquid crystal B. Nematic liquid crystal C. Smectic liquid crystal D. Liquid E. Solid 41. In the figure in question 40 above, what is increasing in the direction of the arrow? A. Temperature B. Pressure C. Order D. Intermolecular forces E. Strength of covalent bonds 42. What is the systematic name of the molecule shown at the right? A. 2,6-diethyl-4,6-dimethyloctane B. 2,6-diethyl-3,5-dimethyloctane C. 3,4,6-trimethyl-6-ethylnonane D. 3,5,7,8-tetramethyldecane E. 3,4,6,8-tetramethyldecane 43. There are several different isomers of trifluorobenzene, C 6 H 3 F 3. How many are there exactly, and how many of those are non-polar (in that order)? A. 2, 1 B. 2, 2 C. 3, 0 D. 3, 1 E. 4, 1

11 Chemistry 101 Final Examination Dec. 16, 2015; Page 11 of A plot of change in potential energy versus distance for two H atoms combining to form H 2 is shown below. At what point (A, B, C, D or E) is this two-atom system the most stable? 45. How many isomers of C 4 H 8 O that contain a carbonyl group (i.e. C=O) are there? A. 1 B. 2 C. 3 D. 4 E The structural formula of vitamin C is shown at the right. The functional groups in vitamin C are: A. Alcohol, alkene, ester B. Hydroxyl, carbonyl, alkene C. Alcohol, carbonyl, ether, alkene D. Ketone, alkene, alcohol E. Carboxylic acid, alkene 47. Vitamin C contains how many chiral centres? A. 0 B. 1 C. 2 D. 3 E. 4

12 Chemistry 101 Final Examination Dec. 16, 2015; Page 12 of The following sketches indicate the s-d bands of five different metals. Predict which of them would exhibit the weakest metallic bonding and therefore have the lowest melting point. 49. Carbon can be found in many different material forms (allotropes). Which of these statements about carbon is incorrect? A. The carbon atoms in diamond are sp 3 hybridized. B. The carbon atoms in graphite and carbon nanotubes are sp 2 hybridized. C. The carbon atoms in graphene are sp hybridized. D. Diamond is a covalent network solid. E. Graphite is an effective solid lubricant. 50. Doping small amounts of boron (B) atoms into silicon (Si) creates what sort of substance? A. insulator B. p-type semiconductor C. n-type semiconductor D. metal E. ionic lattice 51. The molecule C60 is called buckminsterfullerene. Look at the structure carefully and select the INCORRECT statement from the list below. A. The carbon atoms are sp2 hybridized. B. There are 20 five-membered rings in the structure. C. The pi electrons are delocalized throughout the structure. D. The average bond order is 1.33 between each carbon atom. E. There are 60 unhybridized p-orbitals in this structure.

13 Chemistry 101 Final Examination Dec. 16, 2015; Page 13 of A certain solid is moderately hard and has a high melting point. The solid does not conduct electricity but the liquid formed when it is melted does conduct electricity. What class of solid is this substance? A. polymer B. ionic C. metallic D. molecular E. covalent network Polyethylene naphthalate (structure shown below) is a polymer with very good barrier properties against oxygen, making it good for bottling beverages that are susceptible to oxidation, such as beer. Examine the structure below, and answer questions What is the smallest repeating unit in polyethylene naphthalate? (The repeating unit begins with the square bracket on the far left and goes to the lettered square bracket on the right.) Choose from A-E in the figure above. 54. What kind of polymer is polyethylene naphthalate? A. Polyester B. Polyamide C. Polycarbonate D. Polyethylene E. Nylon 55. Which of these is a monomer used in the production of polyethylene naphthalate? A. 1,2-ethanediol B. ethylene (ethene) C. 2-propanol D. carbon dioxide E. ethylethanoate 56. In which of these applications do semiconducting materials NOT play a key part? A. Solar energy cells B. Light-emitting diodes C. Computer chips D. Liquid crystals E. Miniaturized transistors

14 Chemistry 101 Final Examination Dec. 16, 2015; Page 14 of 15 Examine the molecules in the figure below, and answer questions Which molecule has an isomer present amongst the other molecules? A. Q B. R C. T D. X E. Z 58. Which molecule can be produced by reaction of two of the other molecules? A. R B. T C. V D. W E. Y 59. How many of these molecules contain sp 2 hybridized atoms? A. 3 B. 4 C. 5 D. 6 E How many of these molecules are ethers? A. 0 B. 1 C. 2 D. 3 E How many of these molecules can form hydrogen bonds with other molecules like themselves? A. 0 B. 1 C. 2 D. 3 E. 4

15 Chemistry 101 Final Examination Dec. 16, 2015; Page 15 of How many of these molecules have chiral centres in them? A. 0 B. 1 C. 2 D. 3 E How many ketones are there? A. 0 B. 1 C. 2 D. 3 E Which of these statements about techniques that chemists use is INCORRECT? A. X-ray crystallography provides information on bond lengths and angles B. Mass spectrometry provides information on molecular weight C. Infrared spectroscopy provides information on molecular vibrations D. Nuclear magnetic resonance provides information on molecular structure E. Visible light spectroscopy provides information on electron spin 65. Which of the following will NOT make a polymer more rigid? A. Increased crystallinity B. Addition of plasticizers C. Vulcanization D. Cross-linking E. Increased molecular mass 66. If the velocity of an electron travelling at m s -1 in an electron microscope is known to within %, how accurately (in nanometers, nm) can we possibly know its position? (This is a little less than one seventh of the shortest wavelength we can see with the naked eye.) A. 55 B. 28 C. 173 D. E END of EXAM