Сhem 115 Final Exam

Test Form B1 Name _________________________ Chemistry 115-S Section ____________ FINAL EXAM TA ___________________________ Tuesday, 10:20 AM Total Points = 210 December 11, 2007 THIS EXAM IS FOR STUDENTS WITH TUESDAY-THURSDAY 8:30 or 9:30 LECTURE. YOU SHOULD HAVE A RED COMPUTER ANSWER SHEET! Directions: 1. Each student is responsible for following directions. Read this page carefully. 2. Write your name and other requested information on this page and on the separate answer sheet. 3. CODE your name on the answer sheet using an ordinary (#2) pencil. 4. CODE your correct 10-digit identification number (PUID) on the answer sheet. THIS IS VERY IMPORTANT! 5. CODE your section number on the answer sheet. Please use all four digits, 0101, 0102, 0201, etc. This is also very important! 6. CODE the test number shown in the upper right-hand corner of this page onto the answer sheet in the block labeled “Test Form” under the Date line at the top right-hand side. This is Test Form B1. 7. Put all calculations on the examination pages. DO NOT PUT ANY EXTRA MARKS ON THE COMPUTER ANSWER SHEET! 8. This exam consists of 35 multiple-choice questions worth 6 points each. Choose the one best or correct answer for each question and write it both on your exam paper and on the computer answer sheet. The computer answer sheet is the only one that will be graded! 9. This exam consists of 9 pages plus a Table of Useful Information, a Periodic Table and 2 sheets of scratch paper. Please check to be sure that you have them all! KEEP YOUR ANSWERS AND WORK COVERED TO PROTECT THE INTEGRITY OF YOUR WORK!! 115-S − Final Exam (Test B1) − 12/11/07 _____ 1. How many mL of O2 measured at 752 mm Hg and 23.0oC are expected from the complete decomposition of 3.00 g of H2O2? 2 2 H2O2(ℓ) → 2 H2O(ℓ) + O2(g) (a) (b) (c) (d) (e) _____ 2. 1.08 mL 128 mL 1080 mL 84.1 mL 28.1mL A pair of students found that an average of 0.2991 g of sodium carbonate (105.9888 g/mol) was required to react with 25.00 mL of HCl solution. Given the balanced chemical equation below, calculate the concentration of the HCl solution. Na2CO3(s) + 2 HCl (aq) →  2 NaCl(aq) + CO2 (g) + H2O(ℓ) (a) (b) (c) (d) (e) _____ 3. _____ 4. How many atoms of Americium-241 were in a smoke detector that contained 2.0 x 10−4 mg of Americium-241 when it was first made? [241Am = 241.0047 amu]. This radionuclide decays via alpha emission and has a half life of 432.2 years. (a) 2.5 x 1014 atoms (b) 5.0 x 1014 atoms (c) 5.0 x 1017 atoms (d) 2.9 x 1022 atoms (e) 6.02 x 1023 atoms What is the half-life of an isotope if it decays to 12.5% of its radioactivity in 18 minutes? (a) (b) (c) (d) (e) _____ 5. 0.1411 M 0.2258 M 0.1336 M 0.05644 M 0.1129 M 9 minutes 18 minutes 12 minutes 6 minutes 0.17 minutes P-32, a radioisotope used in leukemia therapy, has a half-life of 14.26 days. What percent of a sample remains after 35 days? (a) (b) (c) (d) (e) 20% 82% 4.8% 18% 5.5% 115-S − Final Exam (Test B1) − 12/11/07 _____ 6. _____ 7. One fission reaction of the other nuclide? (a) 75 30 Zn (b) 72 30 Zn (c) 72 30 Co (d) 75 27 Co (e) 75 75 Re The oxygen is the central atom. There is a double bond between the sulfur atom and the oxygen atom There is a single bond between the sulfur atom and the oxygen atom The formal charge on the oxygen is one. The bond angles are slightly less than 120o. Use VSEPR theory to predict the electron pair geometry and the molecular geometry of ClF4−. (a) (b) (c) (d) (e) _____ 10. 0.53 mol 9.0 mol 5.0 mol 4.5 mol 7.0 mol In the best Lewis Dot structure of SOCl2, which of the following statements is true? (a) (b) (c) (d) (e) _____ 9. U, produces 160Sm, three neutrons and another nuclide. What is To completely burn one mole of propanol, C3H7OH, how many moles of O2 are required? (a) (b) (c) (d) (e) _____ 8. 235 Electron pair geometry Tetrahedral Trigonal bipyramidal Trigonal bipyramidal Octahedral Octahedral Molecular geometry Tetrahedral Trigonal bipyramidal See-Saw or teeter-totter Square pyramidal Square planar What is the molecular formula for the following structure? (a) C5H12 (b) C7H14 (c) C7H16 (d) C3H8 (e) C7H12 3 115-S − Final Exam (Test B1) − 12/11/07 _____ 11. _____ 12. What is the formula of the oxide of Al? (a) AlO (b) AlO2 (c) AlO3 (d) Al2O2 (e) Al2O3 Cl, Br, and I, all members of group 7A, form calcium salts with the same calcium-halide ratio because Cl, Br, and I atoms: (a) (b) (c) (d) (e) _____ 13. _____ 14. are the same size. have the same first ionization energy. have the same valence shell configuration. all form diatomic molecules. all are nonmetals. Which of these molecules is not planar? (a) CH2=CF2 (b) BF3 (c) NO3− (d) IF4− (e) NCl3 What is the structure for pentene? 4 115-S − Final Exam (Test B1) − 12/11/07 _____ 15. The addition polymer shown below came from what monomer? _____ 16. Infrared Spectrum I is very similar to the spectrum of four of the five compounds listed below. Spectrum II is that of a fifth compound. Which compound produced Spectrum II? (a) CH3CH3 (b) CH3CH2CH3 (c) CH3CH2CH2CH2CH2CH3 (d) CH3CH2CH2CH=CHCH3 (e) (−CH2CH2−)n 5 115-S − Final Exam (Test B1) − 12/11/07 _____ 17. Hydrogen bonding would be expected to occur in which of the following pure substances? (a) (b) (c) (d) (e) 6 In substance III only In substances II and III In substance III and IV In substance I, II and III In all of these substances OH _____ 18. Isopropyl alcohol ( ) is sold as “rubbing alcohol” in nationwide pharmacies. What types of intermolecular forces would you predict for this molecule? (a) (b) (c) (d) (e) _____ 19. How many liters of ethylene glycol (C2H6O2, also known as antifreeze) must be dissolved in 4.45 kg of water to protect a car radiator to −25.0oC? Ethylene glycol is a nonvolatile nonelectrolyte that has a density of 1.1132 g/mL. Kf for water is 1.86oC/m. (a) (b) (c) (d) (e) _____ 20. Hydrogen bonding and dispersion forces. Dipole-dipole forces and dispersion forces Dispersion forces Ion-dipole forces and dispersion forces Hydrogen bonding, dipole-dipole forces, and dispersion forces 5.37 L 59.8 L 0.851 L 11.3 L 3.33 L A biochemical engineer isolates a bacterial gene fragment and dissolves a 10.0 mg sample of the material in enough water to make 30.0 mL of solution. The osmotic pressure of the solution is 0.340 torr at 25.0oC. What is the molar mass of the gene fragment? [R = 0.08206 L·atm/mol·K] (a) 1.83 x 10−5 g/mol (b) 24.0 g/mol (c) 2.40 x 104 g/mol (d) 1.82 x 104 g/mol (e) 1.82 x 107 g/mol 115-S − Final Exam (Test B1) − 12/11/07 _____ 21. A consequence of the cell membrane being composed of lipids is that the membrane is: (a) (b) (c) (d) (e) _____ 22. accidental drug discovery from mold growing in a petri dish.. the application of forward chemical genetics to develop an antagonist the application of forward chemical genetics to develop an angonist. the application of reverse chemical genetics to develop an antagonist. the application of reverse chemical genetics to develop an angonist. What is the radius of a copper atom? Copper crystallizes in a face-centered cubic unit cell with a cell edge of 360 pm. (a) (b) (c) (d) (e) _____ 25. compounds with the same formulas but different molecular structures. isomers of a compound. a mixture of polymer molecules of different molecular weights. compounds that crystallize in two or more different forms. sulfanilamide drugs. Gleevec was developed to inhibit the action of an enzyme (bcr-abl) that was known to cause Chronic Myeloid Leukemia. This is an example of (a) (b) (c) (d) (e) _____ 24. nonpolar on the inside and outside of the cell, and polar in the middle of the membrane. polar on the inside and outside of the cell, and nonpolar in the middle of the membrane. a polymer. a nonpolar molecule. high in energy. Polymorphs are: (a) (b) (c) (d) (e) _____ 23. 7 127 pm 156 pm 180 pm 255 pm 312 pm Platinum has a density of 21.5 g/cm3 and a molar mass of 195.1 g/mole. How many platinum atoms are in a unit cell if the unit cell edge length is 391.4 pm? (a) (b) (c) (d) (e) 1 2 3 4 5 115-S − Final Exam (Test B1) − 12/11/07 _____ 26. Which is (are) two-dimensional unit cells in the following diagram? (a) (b) (c) (d) (e) _____ 27. _____ 28. Thallium bromide crystallizes in a cubic unit with bromide ions on the corners and a thallium ion at the center of the unit cell. What is the percent by mass of thallium in thallium bromide? (Atomic weights: Tl, 204.38; Br, 79.90.) (a) 71.9% (b) 56.1% (c) 46.0% (d) 29.9% (e) 24.2% All amorphous solids: (a) (b) (c) (d) (e) _____ 29. I II III IV all of these are allotropes. have no ordered internal structure. are ceramics. are one class of crystalline materials. can be used to generate a space lattice. Which is characteristic of most ceramic materials? (a) (b) (c) (d) (e) brittle low melting formed from a melt superconducting composed of molecules 8 115-S − Final Exam (Test B1) − 12/11/07 _____ 30. Which of the following is a semiconductor? (a) (b) (c) (d) (e) _____ 31. What characteristic or property explains why semiconductors have different electrical properties from metals? (a) (b) (c) (d) (e) _____ 32. passing sunlight through several layers of solar cells. capturing solar energy as heat. converting solar energy to electricity in a solar cell. using solar energy to power an LED. using nanomaterials to produce electricity from solar energy. Which of the following elements could be used to create a p-doped germanium semiconductor? (a) (b) (c) (d) (e) _____ 35. 10 m 10 cm 10 mm 10 nm 10 pm “Passive” use of solar energy involves: (a) (b) (c) (d) (e) _____ 34. more valence electrons fewer valence electrons band gap higher critical temperature different coordination numbers The diameter of the nanoparticles you prepared in lab was about: (a) (b) (c) (d) (e) _____ 33. gallium arsenide PVA protein lipids gold Al As P Si Sn Biodiesel is produced from: (a) (b) (c) (d) (e) fats and oils. carbohydrates. proteins. cellulose. cornstarch. 9 115-S − Final Exam (Test B1) − 12/11/07 USEFUL INFORMATION K = 273.15 + ΕC 1 ft3 = 28.32 L PV = nRT R = 8.206 x 10−2 L·atm/(mol·K) E = hυ = hc ! c = 3.00 x 108 m/s ΔE = Δmc2 1 amu = 1.661 x 10−27 kg ! 1 1 1 " = RH $ 2 # 2 % $n & n 2 %( ' 1 h = 6.63 x 10−34 J·s dN = k[N] dt 1 amu = 931.5 MeV !N " ln # 0 $ = kt % Nt & 1 MeV = 6.602 x 10−13 J k t1/2 = ln 2 RH (Rydberg constant) = 1.096776 x 107 m−1 π = MRT 1 J = 1 kg·m2/s2 ΔTb = iKbm 1 atm = 760 mm Hg (exactly) ΔTf = iKfm 0 K = −273ΕC 10