Name _kE:....:..-.:=E=-4y _Chemistry 101 H Hour Exam 3 Fall,2008 Dr. Watson Constants and Conversion Factors: 1 atm = 760 torr = 101.3 kPa 14.7 psi R = 0.08206 L-atm/mol-K g = 9.80 m/s2 3 Li 6.939 4 Be 9.0122 5 B 10.811 6 C 12.011 7 N 14.007 8 0 15.999 9 F 18.998 to Ne 20.183 11 Na 22.990 12 Mg 24.312 13 At 26.982 14 Si 28.086 15 P 30.974 16 S 32.064 17 Cl 35.453 18 Ar 39.948 19 K 39.102 20 Ca 40.08 21 Sc 44.956 22 Ti 4790 23 V 50.942 24 Cr 51.996 25 Mn 54.938 26 Fe 55.847 27 Co 58933 28 Ni 58.71 29 Cu 63.54 30 Zn 65.37 31 Ga 69.72 32 Ge 72.59 33 As 74.922 34 Se 78.96 35 Br 79.909 36 Kr 83.80 37 Rb 85.47 38 Sr 87.62 39 Y 88905 40 Zr 91.22 41 Nb 92.906 42 Mo 95.94 43 Tc (98) 44 Ru 101.07 45 Rh 102.91 46 Pd 106.4 47 Ag 107.87 48 Cd 112.40 49 In 114.82 50 Sn 1\8.69 51 Sb 121.75 52 Te 127.60 53 I 126.90 54 Xe 131.30 55 Cs 132.91 56 Ba 137,34 71 * Lu 174.97 72 Hf 178.49 73 Ta 180.95 74 W 183.85 75 Re 186.2 76 Os 190.2 77 lr 192.2 78 PI 195.09 79 Au 196.97 80 Hg 200.59 81 T1 204.37 82 Pb 207.19 83 Bi 208.98 84 Po (210) 85 At (210) 86 Rn (222) 87 Fr (223) 88 Ra (226) 103 t Lr (262) 104 Rf (261) 105 Db (262) 106 Sg (263) 107 Bh (262) 108 Hs (265) 109 Ml (266) * Lanthanide Series t Actinide Series 57 58 59 60 61 62 63 64 65 66 67 68 69 70 La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb 138.91 140.12 140.91 144.24 (147) 150.35 151.96 157.25 158.92 16250 164.93 167.26 168.93 173.04 89 90 91 92 93 94 95 96 97 98 99 100 101 102 Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No (227) 232.04 (231) 238.Q3 (237) (242) (243) (247) (247) (251) (254) (257) (258) (259)1 1. a). Draw a Lewis structure for the ozone molecule (03), .3"< c.. =IBe S -::. 3;>.. 13 -I S ::= co.. .. ..0=-0-0:~ :0-0=0 .. .-... b).A simple approach to describing the TI bonding in 0 3 would be to construct molecular orbitals from linear combinations of the 2px orbital on each oxygen atom. Assume that 0 3 is linear and let the z-axis be the internuclear axis. • Sketch the shape of the highest energy TI orbital that could be formed by s combining three Px orbitals and indicate whether it is g or u. • Sketch the shape of the lowest energy TI orbital that could be formed by combining three Px orbitals and indicate whether it is g or u. c). Based on your answer to part (a), what kind of hybridization would be used for the central atom in a valence bond description of the sigma bonding in 03? 3 e-f~ = --ap2. ~ s d).Predict the approximate bond angle in the °3 molecule. ---;5 = /ZOo4~ 2. a). Use the VSEPR model to predict the geometry of BrFs: • Draw a sketch showing the electron pair structure of the molecule and name the electron pair geometry. .3r =: 7e.-. S bqtU/.~ 3-+-3 ) l~~ c;:~=~2 • Name the molecular geometry. 3 • Specify the type of hybridization that would be used in a valence bond description of the bonding in this molecule. 3 d2,,¥3= ()~ • Could this molecule be excited by microwave radiation? Explain. 3 Y-Vl/~~~O~ ~~ b).Drawa labeled molecular orbital energy level diagram for the OF molecule. What is its the bond order? Is it diamagnetic or paramagnetic? O=(p.fl F=l _t_J_ ...tl......-n *S+ 1-+-1 z~ --1L -li-iT2 tt P B.D. == i Cflf _ ~ _1'....:...._ * q-b ~ 3. a). Identify the type of transition involved (rotation, vibration, etc.) and its spectral region (IR, UV, etc.) For each of the following: Transition Region~ v=O-+v=1 v'~ 7./l..J@ UV/0A.0-+71 E~ jo ?-~vlk-;?b!:, J::R. ---v=O, J=1 -+ v=l, J=O /!/ivlY'~v=O, J=7 -+ v=O, J=8 ~tir~~ 2p-+ Is E~ fA 1/Ixfl4A()3 b).Draw a diagram to show the P-branch transition and R-branch transition from an initial state having v = 0 and J = 3. Be sure to label each energy level and transition. -~----'7f= I J :1"="Ii" 'U?:I :T:3J --1----,.-,-V"::.IJ.:r=-2 r<-BWttt~ p-~¢\ ---'--_",,!,,--V; OJ :T=:J c). The vibrational wavenumber and rotational constant for HCI are 2990.95 cm-1 and 10.59 cm-1, respectively. Calculate the wavenumber for the transition from v = 0, J = 1 to v = 1, J = 2. E1 2. = %h ~ +Z(3)hCB J5 EOa I = ~ he. -Vv -;.. J (2.) hc.e ~E: = hcp'v + 4 hC-e> -V= I1E = z/,v + 4,B = zqqo.95" + 4 (;1J,stt)he.. -:z/ = 3033• .3 I .6n1.-1 d).Draw an arrow on the diagram and label it with the number given in -parentheses to show each of the following: (1) An electronic excitation (2) A fluorescence transition (3) A vibrational transition >. OJ L.. (4) A phosphorescence transition C (J) W singlet state singlet state Internuclear separation R.5 4 4. a). Determine the height (h) of the mercury column if the sliding lid in the container shown below exerts a pressure of 5.63 atm on the gas inside and the atmospheric pressure is 745 torr. -P~;-r~ = "P~ + -,£ -P., = ~ =5.<alii;;..," 7U1 ""'){az;;, .1 Gus = 427!f \~ b). A container of ammonia initially had a pressure of 5000 psi at 25°C. What was its density? ~v=:; n RT =-: RT p =: .m _ wp := (l7¥7l?~(5Oc;of~xJ V-,{7.7pJ ~ V ..e...T [0, ~f;ff:)(Z98") c). After a period of time, the pressure in the container of part (b) increased to 5300 psi due to the decomposition of some of the ammonia via the reaction 2NH3 -3H2 + N2 · Calculate the partial pressure of the H2 that had formed. S30CJ = 5"000-2)( + 3x + X == Soco+ 2.X~:: ::;-zx ~ rNL. , _ 4S-0~5 d) .According to the kinetic theory of gases, • What causes pressure? ~ i.&. ~~.1k~o/~~. • What is the momentum change of a molecule having x-velocity component Vx when it collides with the yz wall? Af)( = -2mvx --• What property of molecules does temperature measure? 21 /~~~~o/.tk~~ ~~.7.k~j L
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