20A_final_exam_solns

20A_final_exam_solns - If}; 00PM +- MAC/3L 20A Final Exam...

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Unformatted text preview: If}; 00PM +- MAC/3L 20A Final Exam ’ 7/31/2006 By signing this e am, I agree that I have neither given nor received assistance on this exam. All work presented here is my own. ' ’ Signature (Unsigned exams will not be graded.) This exam consists of 10 problems, and should have 11 separate pages. Read through all of the problems before beginning, and start with those you know best. Read each problem carefully, as several of the questions have several parts. The back two pages of the exam contain a page of equations and constants and a periodic table. Please feel flee to remove either or both of these pages. Please make sure to put your name on each page. If you require more space than that given for each problem, use the back of the question page, but indicate that you have done so. Credit will not be given for illegible answers or answers alone. Show your work! (Remember, partial credit is your friend.) Please make final answers clear. Where appropriate, answers should contain an appropriate number of significant figures. 1. Give the systematic name or molecular formula (as appropriate) for each of the following compounds: (24 points) a) TiOz wwm om»th b) Sodium thiocyanate N a g ® © CD .6) c) [FC(CO)6] Mambowg/imfl CO) d) potassium hexacyanoruthenateafl) K [mch @‘7’ 1CD @ 6) [C°(NH3)4(0H)2]C1_ f) CH3-C EC—CH-CHz-CH3 éHzCH3 ‘ 3 ’M J 4 - Wt @ 8) CH3 | momm @ CHg-CH-CH-CHz-CHz-CHz-CHg 4) 5 ' l CH2 CH2 CH3 h) 1-methy1-2-nitro-cyclooctane 21943 L0 \/\ \Pt 6’ CONS: 2‘9: mun . ‘ Wdr e‘ wag/Lam 2 2. Give the oxidation state and electronic structure of the transition metal in each of the following compounds. (You may use the noble gas abbreviations). In addition, draw both the high and low spin electron configurations (be sure to label which is which) assmm'ng an octahedral geometry. (28 points) a) [Emmet] b) [Co(H20)5§r]1§}2 Co 3+ [m 5A“ c) §[Co(co)(él‘)51 Co“ [Rd % cl 5 +2, +2 _\ d) Mg[Hg(CN)4] H324— CXE] 53W &o®$ELW All 435.2 ___‘:__.i/‘1. ii 1.1.7 W @A 5E Wu '1 __ l-Zl; 3a). List the different types of vibrations you would expect to see in an infrared (vibrational) spectrum of methanol. (6 points) 2. c~o 2W [2) 3. O_\—\ (:9 b) How many peaks would you expect to see in a proton NMR spectrum of methanol? What would be their relative areas? (5 points) 2 L5 @ W \Qfl‘ 3x Oj’Lch (56 SH i I U) fl 4. List W e I: er you would expect the following compounds to be clear or brightly colored. Briefly state your reason why. (9 points) =5 no d9 &WV\E)«U{1§VISJ 21) K2[Hg14] 1 {452+ 97 die a“ b) K3[C1’(CN)6] ‘ Cr 2>+~’_a [M31353 Mon CSIAfiLS. , C, C9 C2) >\: \A 5. Consider the molecule IH—81Br, which has an equilibrium bond length of 1.424 x 10'10 m. What is the moment of inertia of this diatomic molecule? (The atom masses are 1.0078 amu and 80.916 amu respectively). (8 points) PM“? = WW>RJ C9 ma"W\P>r‘ (LLDLDHLID‘flki >(1.sz4><lo"v°m>2’ 1 am .— _L : (llooq,8am (80.9(tocwku> O , 00%?) [MM + 80 mo 4mm.) our»wa -42]— , . 2 8 L 4." 3 kflmL 0 b) What wavelength of light will be absorbed in exciting HBr from the J=1 to the J=2 rotational state? (8 points) _ T? Z 2 5E: be 2/1": [34(31+‘>’37<ICH>] :r;=\ )\ 8W1: 'L h, _ /\ z 3:913). Q) -§~ = ST‘ZLCO Z> . k. '2. - 7‘ 1‘ (z'qq8X108)CZ>C1—r><3~353>UD 4 125m > (L9.Lo2_tox10'3>4l"s) : [OpLéYYX‘ c). What is the population of the 10th rotational excited state of HBr (relative to the population of the ground state) at 400 K? (8 points) - W ( HO 2 "’ E ’ ED) 1 2:1. £54 S- “’— NED _ PUD WP C L° g \ P £81111 “Es—r Co) RE;— No @ g (meg eaaxto’“ ham % -3quimwfl : 2| QM? E“ (‘0 \£ to l><uquk><|t38| X1013, E 6. Draw Lewis dot diagrams for the following molecules, give their steric number, predict both their overall and atom only geometries, and give the hybridization of orbitals on the central atom. (In the case of a) and d) the central atom is listed first). (24 points) a)1>0013 bash chasm am. @ c) CH3CHCHCH3 (give the hybridization of each carbon atom, and the angles between the carbon atoms, rather than the geometries). H \ / H (bum/s Chico) C if; /\/ [7’05 [200 593 39“ SFCL $133 d) Br04‘ MP. @3er CD may p- 7. Sulfuric acid (112804) is formed by the reactionof sulfur dioxide, oxygen gas, and water. Write down the balanced chemical equation for the creation of sulfuric acid. (8 points) (2503 + ca +aHZo—~> 262304 @D @ b) If 100.0 g of each of the three starting materials are combined, which will be the limiting reagent? How much sulfuric acid (in grams) will be formed? (10 points) MW 30;: chojhnek MN 02: 32.003(mo~Q MN H20: l8.ol gin/ich WWO H2504: (Moej/mol Jig hmdms (00.0 , {MSOL 3 1.5m! M 50; Maggi/oi bio I, it 5 (pL'flObS aim/kw 2mm 66 ) “50% ‘ M‘MDL « 3%“th Riki‘s Cole 7 8a). Write down the entire molecular electronic structure of the diatomic F2. What is the bond order of this molecule? Is it paramagnetic or diamagnetic? (8 points) <9 (07 $321 at: 721525)? 0-2: 31071? 3103 F 5Tngva (m; TF1: jg} @ bemdtmoiJmZéégb): l G b). Write down the entire electronic structure for the diatomic ion 132+. What is its bond order? Is it paramagnetic or diamagnetic? (8 points) @ m mt)“-(we:reanmxmml(may @ loot/bi Mm: é<8~5> ‘ g/Z— ® pmdmagmfio 9. In order for a beam of electrons to produce an interference pattern on a screen, the wavelength of the electrons must be greater than or equal to the distance between the two slits through which the electrons pass. Given this condition, what is the maximum velocity the electrons can have in order to produce an interference pattern fi'om slits separated by 2.00 nm? (8 points) a C79 )2. ZDOxlO~ m \I— (pow 1W” 3‘3 z 3‘94”) “WO'O’VVD (Q‘IOOWLO k3 10. An organic molecule with a conjugated 1t electron backbone absorbs light at 450 nm (blue), in exciting an electron fiom the ground to the first excited state. What color does this molecule appear? (3 points) ; (086mm % amt) (39 %L "‘5 b) Assuming th delocalized 1t electron in this molecule behaves like a particle in a one-dimensional box, what is the length (in meters) of the box in which the electron is confined? Recall that E hzn2 for a particle in a one-dimensional box. (7 points) "-8mL2 L fltzl Ezb£=b-L<fl ’HU' m=l ® A % amt F (9 L2: m (paw 8mc ’ 8(W1qulb'g‘g>(2.%8xloam/s> L1: 1.3m XIO'mML do 0143qu i is bvt L , 0) Given that the molar extinction coeflicient o s molecule is 6930 L/(cm mol), what path length cell must you use for a 100 M solution to transmit 50% of the light at 450 nm? (10 points) @ T: 0.60 -: A: fl: _JQm<cT—> _ —,QV\(©«E50> @ ‘ ———-——————-—--— ~ ,',. QQEOL’ C E (“DONG ww%>< Cm . met g 79566 / {111.00 QM 'm Equations, Constants, and Conversion Factors NA=6.022 x10"3 atoms/mol 112 Em h=6.626x 10-341 s 7‘ 2 ‘ Idiatomic = “Re ao=0.5292 x10"10 m E _b = he)“, + é) k13=1.381x10'23 MC 0): _1_ 5 2n e=1.602 x10"19 C u H: mlmz m¢=9.109 x 1031 kg m1+ m2 mp=1.673 x10'27 kg 1 :3 P mn=1.675 )(10'27 kg h Mp2— 1::o=8.854x10'12 Cz/(Jm) 4" c=2.998 x 108 m/s hc Ephoton = T 1 amu=l.661 x 10'27 kg E _ — Zze4me 1eV=1.602x10’19J n — —883n2h2 1rydberg=2.180x10'18]=13.61eV E _ Z2 n - _—T n hc=1240 eVnm _N_J_= g(J) ex“ _ (E: - EU} IJ=1kgm2/s2 No g(0) ‘ kBT .g(J)m = 21 + 1 gang, = 1 KB = lz-mev2 —-1n(T)=A=csl _ 2 V(r) = 26 KB =hV "(D 4113 or p=__13_5 Hw = Ew 0 2082 mBZ HEM—Am— m—flfi m0 mam—Ag UmflOmMM—m ...
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20A_final_exam_solns - If}; 00PM +- MAC/3L 20A Final Exam...

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