15781_e_8897

15781_e_8897 - PROF. ROBERT ANGELICI FALL 2004 THIS EXAM...

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Unformatted text preview: PROF. ROBERT ANGELICI FALL 2004 THIS EXAM CONSISTS OF 17 QUESTIONS ON 7 PAGES GRADING POINTS 16 pts 13 pts 28 pts 23 pts 20 pts 100 pts CHEM 167 HOUR EXAM II OCTOBER 4, 2004 NAME______________________ RECIT. INSTR._______________ RECIT. SECT.________________ PAGES Page 2 Page 3 Page 4 Page 5 Page 6 TOTAL SCORE ________ ________ ________ ________ ________ ________ Teaching Assistants and Recitation Sections Name Sections Time Lynnette Bauman 1, 7, 17 8:00, 12:10, 11:00 Sarah Cady 2 9:00 Patricia Dailey 12, 13 3:10, 8:00 Laura Gengelbach 5, 15 10:00, 9:00 Nihal Kaissieh 11, 18, 22, 23 2:10, 12:10, 3:10, 4:10 Chun Lu 19, 21 1:10, 2:10 Kevin McWilliams 6, 9 12:10, 1:10 Gregg Schieffer 4, 14 10:00, 9:00 Kale Swainston 3, 16 9:00, 10:00 Kuldeep Wadhwa 10 1:10 Molly Warnke 8, 20 1:10, 2:10 Rules for the Exam: 1. Show all of your work on these exam pages. Numerical answers should be given in the correct number of significant figures and units. Put your answers in the answer spaces. 2. The last page contains useful information and a periodic table. THE ANSWER KEY TO THIS EXAM WILL BE POSTED ON BULLETIN BOARD #4 IN THE HALLWAY EAST OF ROOM 1002 GILMAN AND ON THE CHEM 167 WEBSITE. CHEM 167 FINAL EXAM TUESDAY, DECEMBER 14 7:00 – 9:00 P.M. 2 1. (7 pts) Given the following heats of reaction, 2 ClF(g) + O2(g) Æ Cl2O(g) + F2O(g) ∆H = +167.4 kJ/mol 2 ClF3(g) + 2 O2(g) Æ Cl2O(g) + 3 F2O(g) ∆H = +341.4 kJ/mol 2 F2(g) + O2(g) Æ 2 F2O(g) ∆H = –43.4 kJ/mol Calculate ∆H (in kJ/mol) for the following reaction: ClF(g) + F2(g) Æ ClF3(g) Answer____________________ 2. (9 pts) Calculate the wavelength (in m) of a photon emitted by a hydrogen atom when its electron drops from the n = 5 level to the n = 3 level. Answer____________________ 3 3. (3 pts) What is meant by “the dual nature of an electron”? (circle one) a) b) c) d) 4. It may have an ms quantum number of +1/2 or –1/2. It may have a + or – charge. It is attracted by a positive charge and repelled by a negative charge. It has properties of both a particle and a wave. (3 pts) Why does LiCl give a red flame when it is heated in a flame? a) b) c) d) Light is emitted when electrons in the LiCl fall from higher energy orbitals to lower energy orbitals. White light from the room lights is absorbed by the LiCl. The LiCl reacts when heated to give a red compound. Light is emitted when electrons in LiCl are excited by the heat from lower energy orbitals to higher energy orbitals. 5. (7 pts) What is the ∆H for the combustion of 1 mole of propane (C3H8) according to the following balanced equation: C3H8(g) + 5 O2(g) Æ 3 CO2(g) + 4 H2O(l) Given the following ∆H o values: f cpd C3H8(g) CO2(g) H2O(l) † C2H6 ∆H o , kJ/mol f –103.9 † –393.5 –285.8 –84.7 Answer____________________ 4 6. (8 pts) The pressure of the air in an automobile tire on a cold day at –11 ˚F is 32.0 psi (lbs per square inch). What would be the pressure (in psi) in the tire on a warm day at 95 ˚F? (The change in the volume of the tire is negligible.) Answer____________________ 7. (4 pts) How many unpaired electrons are in the ground state of an Fe atom? Answer____________________ 8. (4 pts) Which one of the following is diamagnetic? (circle one) P+ P– P2– P3– 9. (3 pts) Which one of the following is the correct Lewis dot symbol for a lead atom? (circle one) • P•b • Pb • • P•b • • P•b • • • Pb • • 10. (3 pts) Which one of the following is the correct Lewis dot symbol for the S2– ion? (circle one) S• • 2– S 2– • S• • 2– • S• • • 2– S• 2– 11. (6 pts) Considering the Lewis dot symbols of the reactants, give the correct formulas of the products in the following reactions: a) Mg + Se Æ _______________ b) Na + P Æ _______________ c) Al + Br Æ _______________ 5 12. (11 pts) The amount of heat required to raise the temperature of 1.00 L of water by 10.0 ˚C is 41.84 kJ. How much heat (in kJ) is required to raise the temperature of 1.00 L of N2 gas (at 725 mmHg and 25.0 ˚C) by 10.0 ˚C? (specific heat of water is 4.184 J/g ˚C, specific heat of N2 gas is 1.07 J/g ˚C, density of water is 1.00 g/mL) Answer____________________ 13. (3 pts) Two moles of Cl2 gas at 20.0 ˚C are heated to 350 ˚C while the volume is kept constant. The density of the gas (circle one) a) increases b) decreases c) remains the same d) Not enough information is given to correctly answer the question. 14. (9 pts) Calculate the work done (in J) by the reaction 2 Na(s) + 2 H2O(l) Æ 2 NaOH(aq) + H2(g) when 0.34 g of Na(s) reacts with excess water to form H2(g) at 0.0 ˚C and 1.0 atm pressure. Answer____________________ 6 15. (11 pts) How many moles of photons of red light (l = 6.55 ¥ 10–7 m) would be required to heat 1.00 g of water from 25.0 ˚C to its boiling point at 100.0 ˚C? Assume that all of the light is absorbed by the water. (specific heat of water is 4.18 J/g ˚C) Answer____________________ 16. (6 pts) Below are given electron configurations for atoms in an excited state. Write the symbol of the element and the ground state electron configuration of the element. a) 1s22s22p64s1 element electron configeration b) [Ar] 4s13d104p4 element electron configeration 17. (3 pts) Which one of the following sets of quantum numbers is not possible? n 4 3 3 2 2 l 3 0 0 1 0 ml –2 1 0 1 0 ms +1/2 –1/2 +1/2 –1/2 +1/2 a) b) c) d) e) 7 Information PV = nRT E = hn ln = c E=– 2.178 ¥ 10-18 J / atom n2 3.00 ¥ 108 m/s 6.63 ¥ 10–34 Js 6.02 ¥ 1023 0.0821 L•atm/mol K 8.314 J/mol K 1.00 L•atm = 101.3 J q = ms∆t † l= h mn ∆E = ∆H – P∆V † ˚F = 9 ˚C + 32.0 5 K = ˚C + 273.1 † 1A 1 1 H 1.01 3 Li 6.94 11 Na 23.0 19 K 39.1 2A 2 Periodic Table of the Elements 8A 18 2 5A 6A 7A He 15 16 17 4.00 9 10 7 8 F Ne N O 14.0 16.0 19.0 20.2 18 15 16 17 Ar P S Cl 31.0 32.1 35.4 39.9 36 33 34 35 Kr As Se Br 74.9 79.0 79.9 83.8 54 51 52 53 Xe Sb Te I 122 128 127 131 85 86 83 84 At Rn Bi Po 209 (209) (210) (222) 3A 13 5 B 10.8 10 1B 11 29 Cu 63.5 47 Ag 108 79 Au 197 2B 12 30 Zn 65.4 48 Cd 112 80 Hg 201 13 Al 27.0 31 Ga 69.7 49 In 115 81 Tl 204 4A 14 6 C 12.0 14 Si 28.1 32 Ge 72.6 50 Sn 119 82 Pb 207 4 Be 9.01 12 Mg 24.3 20 Ca 40.1 37 38 Rb Sr 85.5 87.6 55 56 Cs Ba 133 137 87 88 Fr Ra (223) 226 8B 3B 3 4B 4 5B 5 6B 6 7B 7 25 Mn 54.9 43 Tc (98) 75 Re 186 107 Uns (262) 8 26 Fe 55.8 9 21 22 23 24 Sc Ti V Cr 45.0 47.9 50.9 52.0 39 40 41 42 Y Zr Nb Mo 88.9 91.2 92.9 95.9 57 72 73 74 La Hf Ta W 139 178 181 184 89 104 105 106 Ac Rf Ha Unh 227 (261) (262) (263) 27 28 Co Ni 58.9 58.7 44 45 46 Ru Rh Pd 101 103 106 76 77 78 Os Ir Pt 190 192 195 108 109 Uno Une (265) (266) Lanthanides Actinides 58 Ce 140 90 Th 232 59 Pr 141 91 Pa 231 60 61 62 63 64 65 66 67 68 69 70 71 Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 144 (145) 150 152 157 159 162 165 167 169 173 175 92 93 94 95 96 97 98 99 100 101 102 103 U Np Pu Am Cm Bk Cf Es Fm Md No Lr 238 (237) (244) (243) (247) (247) (251) (252) (257) (258) (259) (260) ...
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