Final Exam with Answer Key - General Chemistry | CHEM 1035, Exams of Chemistry

Download Final Exam with Answer Key - General Chemistry | CHEM 1035 and more Exams Chemistry in PDF only on Docsity! Chemistry 1035 Final Exam December 10, 2007 THIS IS FORM A Name c = 3.00 x 10 8 m/s h = 6.63 x 10 -34 J • s R = 0.0821 L atm mol K i i or 8.314 x 10-3 kJ/K mol Choose the single best answer to each question. 1. How many of these numbers have only 4 significant figures? 1.05 x 103 0.0052 11.210 5.060 1. one 2. two 3. three 4. four 2. Convert 2.00 m/min to ft/hr(1 in = 2.54 cm) 1. 6.56 ft/hr 2. 21.7 ft/hr 3. 4720 ft/hr 4. 394 ft/hr 3. Iron has a density of 7.86 g/mL. The volume occupied by 16.5 lb of iron is (1 lb = 453.6 g) 1. 952 mL 2. 2.09 L 3. 588 mL 4. 1.43 L 4. How many protons, neutrons and electrons does 58Ni2+ have? 1. 28p, 58n, 30e - 2. 30p, 58n, 30e - 3. 30p, 28n, 28e - 4. 28p, 30n, 26e - 5. A +3 ion with 41 electrons and 57 neutrons would be an isotope of the element 1. La 2. Ru 3. Sr 4. Nb 6. Which of the following pairs of names and formulas is incorrect? 1. Cl2O7 dichlorine heptaoxide 2. Ca3(PO4)2 calcium phosphate 3. H2SO3 hydrosulfurous acid 4. Cr2O3 chromium (III) oxide 7. An unknown element reacts with bromine to form an ionic compound whose formula is XBr3. If ion X has 10 electrons, identify the element. 1. Mg 2. Si 3. Al 4. Ne 8. What is the correct formula of iron (II) chlorate? 1. Fe(ClO3)2 2. Fe2ClO4 3. FeClO4 4. Fe(ClO)2 9. Calculate the mass of 1.11 x 1023 molecules of SO2. 1. 11.8g 2. 23.5g 3. 34.7g 4. 56.1g 10. Calculate the number of Cr atoms in 78.82 g of K2Cr2O7. 1. 3.228 x 1023 atoms 2. 4.725 x 1025 atoms 3. 1.774 x 1024 atoms 4. 4.512 x 1023 atoms 20. Select the correct set of quantum numbers ( n, , m , ms ) for the highest energy electron (last electron added) in the ground state of Al. 1. n = 3, = 0, m = 0, ms = ½ 2. n = 3, = 1, m = -1, ms = ½ 3. n = 3, = 2, m = -2, ms = ½ 4. n = 2, = 1, m = 1, ms = ½ 21. Calculate the energy of radiation with a wavelength of 360 nm. 1. 1.17 x 10 19 J 2. 5.52 x 10 -19 J 3. 4.47 x 10 -22 J 4. 7.52 x 10 -18 J 22. Which of the following has 2 unpaired electrons? 1. Ba 2. I 3. W 4. Se 23. The total number of electrons in p orbitals in an atom of antimony, Sb is 1. 6 2. 12 3. 21 4. 31 24. The elements Sr, S, Si and Sn have the following ionization energies (NOT IN THE CORRECT ORDER): 1000 kJ/mol, 786 kJ/mol, 709 kJ/mol and 550 kJ/mol. Which element has the ionization energy of 1000 kJ/mol? 1. Sr 2. S 3. Si 4. Sn 25. The successive ionization energies (IE) of a certain element in kJ/mol are; IE1 = 590; IE2 = 1145; IE3 = 4912. Which of the following is the element? 1. Rb 2. P 3. Ca 4. Ga 26. Select the compound with the highest lattice energy. 1. NaF 2. MgF2 3. LiCl 2. MgCl2 27. Which of the following has a central atom that has no unshared pairs? 1. PH3 2. BrF5 3. PCl5 4. H2S 28. The molecular geometry of PCl4 - is 1. tetrahedral 2. see-saw 3. square planar 4. T-shaped 29. What kind of hybridization does the central atom P use in PH3? 1. sp 2. sp2 3. sp3 4. sp3d 5. sp3d2 30. Which species does not obey the octet rule? 1. SF4 2. AsCl3 3. CF4 4. SO2 31. Which of the following is not a flat (planar) species? 1. CO32 - 2. SO2 3. ICl3 4. AsCl3 32. Which of the following statements about CO32 - is true? 1. The bonds are polar and the ion is nonpolar. 2. The bonds are polar and the ion is polar. 3. The bonds are nonpolar and the ion is polar. 4. The bonds are polar and the ion is nonpolar. 33. Calculate the heat of reaction for the following reaction: N N + 2 H N H H 3 H H Bond: N≡N H-H N-H Bond energy (kJ/mol): 945 432 391 1. –969 kJ 2. 1068 kJ 3. –452 kJ 4. -105 kJ 34. The positive end of a polar bond is toward the atom that has 1. the higher ionization energy. 2. the smaller electronegativity value. 3. an unshared pair. 4. the smaller number of valence electrons. 35. In which of these substances are the atoms most likely held together by polar bonds? 1. H2NO3 2. F2 3. Li3N 4. FeO 36. Calculate the volume occupied by 25.2 g of CH4 at 25°C and 0.975 atm. 1. 17.6 L 2. 24.2 L 3. 11.2 L 4. 39.5 L 46. A first-order reaction has a rate constant of 0.00300/s. The time required for the concentration of reactant to drop to 15% of the initial concentration is 1. 275 s 2. 316 s 3. 54.2 s 4. 632 s 47. Which of the following quantities decreases as the temperature of a reaction increases? 1. reaction rate 2. Ea 3. k 4. t1/2 48. Given the following mechanism: Cl + O3 → ClO + O2 O + ClO → Cl + O2 What is the catalyst? 1. O 2. Cl 3. ClO 4. O2 5. O3 49. Calculate the rate constant at 43°C for a reaction if k = 5.8 x 106/Ms at 25°C and Ea = 92 kJ/mol 1. 6.4 x 107 / M•s 2. 2.0 x 107 / M•s 3. 4.8 x 107 / M•s 4. 5.3 x 108 / M•s 50. The catalyzed pathway in a reaction mechanism has a activation energy and thus causes a reaction rate. 1. higher, lower 2. higher, higher 3. lower, higher 4. lower, lower 5. higher, steady (Answers on next page) Answers: 1. 1 26. 2 2. 4 27. 3 3. 1 28. 2 4. 4 29. 3 5. 2 30. 1 6. 3 31. 4 7. 3 32. 1 8. 1 33. 4 9. 1 34. 2 10. 1 35. 1 11. 3 36. 4 12. 4 37. 1 13. 3 38. 2 14. 4 39. 1 15. 2 40. 3 16. 2 41. 4 17. 2 42. 1 18. 2 43. 2 19. 2 44. 1 20. 2 45. 1 21. 2 46. 4 22. 4 47. 4 23. 3 48. 2 24. 2 49. 3 25. 3 50. 3