CHM 1045 (Dr. Light)FINAL EXAM (Purple) Name__________________________ April 24, 1996 (please print) Recitation Section_______ Soc.Sec.Num._____________________ Lecture Section (Circle one): 8:00 am 12:20 am This exam consists of 6 pages. Make sure you have one of each. Two additional pages contain some thermochemical data, a table of electronegativities, and a periodic chart. You may tear them off, and use the back of them for scratch work. Print your name at the top of each page now. Show your work on calculations, including unit conversions, and give answers in the correct units and appropriate number of significant figures. For one point extra credit, put the atomic weight of oxygen at the top of page 2. If anything confuses you or is not clear, raise your hand and ask! (6)1.Complete and balance the following chemical equations. In cases where the name of the substance is given, give the formula under the name. In cases where a ? is given, fill in the missing compound under the ?. (a)sodium hydroxide + chloric acid ----> sodium chlorate + ? (b)C6H12O6 + O2 ------> ? + ? (4)2.Give the atomic symbol, including Z, A, and q in the proper location, for atoms or ions containing the following number of particles: (a)17 protons, 18 neutrons, (b) 26 protons, 30 neutrons, 18 electrons 23 electrons (5)3.A compound containing P, O, and Cl yields the following analysis: 20.2% Phosphorus, 10.4% Oxygen, 69.4% Chlorine. Determine the empirical formula. 4.Given the following balanced chemical equation: 2 Al(s) + 3 H2SO4(aq) -----> Al2(SO4)3(aq) + 3 H2(g) (3)(a)How many grams of Al will be required to produce 48.9 g of hydrogen gas? (b)3.5 Moles of Al are added to a solution containing 5.1 moles of H2SO4. (2)(1)Which reagent is limiting? (2)(2)How many moles of the excess reagent will remain after the reaction? (2)(3)How many moles of H2 will be produced in the reaction? (5)5.How many L of a 0.23 M solution of KOH is required to neutralize 0.26 L of a solution of 0.47 M H3PO4? Write the equation for the reaction. 6.Calculate the þH for the following reaction in three different ways, using the thermochemical data given at the end of the test: C2H4(g) + H2O(l) -----> C2H5OH(l) (4)(a)Using heats of combustion data. (4)(b)Using heats of formation data. (4)(c)Using bond energy data. (4)7.How many joules of heat energy will be required to raise the temperature of 15 grams of ice from -45oC to liquid water at 95oC? (4)8.What is the energy of a mole of photons having a wavelength of 210 nm? (4)9.What is the wavelength of a photon of light emitted by a hydrogen atom in which the electron drops from the fourth Bohr orbit to the first Bohr orbit? (3)10.Write the abbreviated electron configuration (using the rare gas core, i.e. C = {He}2s22p2) for the following: Mn P As (4)11.Give the value of the quantum number l associated with electrons in each of the following orbitals: 3s 4d 2p 3d l = ______ ______ ______ ______ (3)12.Comparing the elements Li and K, which (a) Has the highest ionization energy? ______ (b) Has the largest atomic radius? ______ (c) Is most reactive with water? ______ (3)13.Comparing the elements Ca and Se, which (a) Has the highest ionization energy? ______ (b) Has the largest atomic radius? ______ (c) Forms an oxide which reacts with water to produce a basic solution? ______ (12)14.For each of the following compounds or ions, draw the best Lewis dot structure. (If more than one resonance structure is "best", draw only one). The central atom is underlined. Give the electron pair geometry, the molecular geometry, and the hybridization about the central atom. CompoundLewis Structure electron pair molecular hybridization geometry geometry POCl3 CH2Cl2 XeF2 (3)15.Draw three Lewis Dot resonance structures for ClO3-1 in which the central chlorine atom has a zero formal charge. Label the formal charges on each oxygen. Must the octet rule be violated to draw these structures? (5)16.What volume of oxygen, measured at 273 K and 1.00 atm pressure, must be used to completely burn 22.0 grams of C3H8.? (Write the balanced equation for the reaction). (5)17.A 0.500 L lecture bottle of gas contains a mixture of 75.0 mole % nitrogen, 15.0 mole % oxygen, and 10.0 mole % CO2 at 25 oC and 16.1 atm pressure. How many moles of each gas are present in the cylinder? (2)18.Which of the following compounds is expected to have the highest boiling point? (Circle your answer). CH3OHCH3OCH3 CH3Cl CH3SH HCl (7)19.From the phase diagram for H2O below, identify the letter on the diagram corresponding to: (a) Liquid water ______ (b) Ice ______ (c) Water vapor ______ (d) Normal boiling point ______ (e) Normal melting point ______ (f) Triple point ______ (g) Critical point ______ The following tables of data may be useful to you. Physical constants: c = 3.00 x 108 ms-1;h = 6.63 x 10-34 J-s;RH = 2.18 x 10-18 J N = 6.02 x 1023 particles/mole; R = 0.082058 L-atm mol-1 K-1 1 atm = 760 torr þH of fusion of ice = 6 kJ/mol; þH of vaporization of water = 40.6 kJ/mol; Specific heat of ice = 2.09 J/g-K; Specific heat of water = 4.18 J/g-K; Heats of Formation: þHfo CaCO3(s)= -1207.1 kJ/molþHfo CaO(s) = - 635.5 kJ/mol þHfo CO2(g)= - 393.5 kJ/molþHfo CO(g) = - 110.5 kJ/mol þHfo CH3OH(l)= - 238.6 kJ/molþHfo Mg(g) = 147.1 kJ/mol þHfo Mg+(g)= 885.1 kJ/molþHfo Mg2+(g) = 2335.1 kJ/mol þHfo H2O(l)= - 285.8 kJ/molþHfo H2O(g) = - 241.8 kJ/mol þHfo C2H4(g)= 52.30 kJ/molþHfo C2H5OH(l) = - 277.7 kJ/mol þHfo C2H2(g)= 226.7 kJ/molþHfo C2H6(g) = - 84.68 kJ/mol þHfo MgO(s)= - 601.8 kJ/molþHfo LiCl(s) = - 408.3 kJ/mol þHfo Li(g)= 159.3 kJ/mol þHfo Li+(g) = 685.7 kJ/mol þHfo Cl(g)= 121.7 kJ/mol þHfo Cl-(g) = - 227 kJ/mol þHfo F(g)= 80.0 kJ/mol þHfo F-(g) = - 252 kJ/mol Heats of Combustion (H2O(l) as product): þHcomb C(s)= -393.5 kJ/mol þHcomb CO(g) = -283.0 kJ/mol þHcomb CH4(g)= -890 kJ/molþHcomb H2(g) = -285.9 kJ/mol þHcomb C3H8(g)= -2220 kJ/molþHcomb C6H6(l) = -3267 kJ/mol þHcomb CH3OH(l)= -726.5 kJ/molþHcomb C2H5OH = -1366.7 kJ/mol þHcomb C2H4(g)= -1410.9 kJ/molþHcomb C2H2(g) = -1299.6 kJ/mol þHcomb C2H6(g)= -1559.7 kJ/molþHcomb C6H12H6(s)= -2816 kJ/mol Average Bond Energies (kJ/mol): Single Bonds: C-H413N-H391 O-H 463 F-F 155 C-C348N-N163 O-O 146 C-N293N-O201 O-F 190 Cl-F 253 C-O358N-F272 O-Cl 203 Cl-Cl 242 C-F485N-Cl200 O-I 234 C-Cl328N-Br243 Br-F 237 C-Br276 S-H 339 Br-Cl 218 C-I240H-H436 S-F 327 Br-Br 193 C-S259H-F567 S-Cl 253 H-Cl 431 S-Br 218 I-Cl 208 Si-H323H-Br366 S-S 266 I-Br 175 Si-Si226H-I299 I-I 151 Si-C301 Si-O368 Multiple Bonds: C=C 614 N=N 418 O2 495 CðC 839 NðN 941 C=N 615 S=O 523 CðN 891 S=S 418 C=O 799 CðO 1072 Some Electronegativities H 2.1 (2A) (3A) (4A) (5A) (6A) (7A) Li 1.0 Be 1.5 B 2.0 C 2.5 N 3.0 O 3.5 F 4.0 Na 0.9 Mg 1.2 Al 1.5 Si 1.8 P 2.1 S 2.5 Cl 3.0 K 0.8 Ca 1.0 Ga 1.6 Ge 1.8 As 2.0 Se 2.4 Br 2.8 [Transition Metals 1.0-2.4] Rb 0.8 Te 2.1 I 2.5 Cs 0.7 Po 2.0 At 2.2