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practice_final_a_key - Chemistry 26 Practice Final December...

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Unformatted text preview: Chemistry 26 Practice Final December 2003 Instructions 0 The practice final mostly contains new material. 0 Actual Final Exam will be longer. 0 The last page contains the useful information that you will see on the Final Part 1. Multiple Choice — Circle the single Best Answer. 1. Consider the mechanism: 03(g) ¢> 02(g) + O(g) O(g) + 03(g) —> 202(g) Fake. 2: LO ’31 fast; reaches equilibrium slow What is a reasonable rate law? A) rate = k1 [03] B) rate =k2[03][0] a r r/ 4» \2‘1‘ {67; ” C) rate = k’ [03]2[02] VI ’ ‘ ) ‘ rate = k’[O3][02] 2 D (65 N83: 2. Consider the mechanism: 03(g) <:> 02<g> we?“ + 03(g) a 202(g) fast; reaches equilibrium slow What is the overall reaction? A) 03 —> + B 302<g) —> 203<g) @ 203(g> —> 302(g) D) 20(g) —> 02(g) E) None of the above 3. Consider the mechanism: 03(g) ¢> 02(g) + O(g) fast; reaches equilibrium O(g) + 03(g) ——> 202(g) slow An intermediate in this reaction is ) 02(g) B) O(g) ) 03(g) D) 02(g) and 0(g) E) There is no intermediate in this reaction. 4. The nuclear equation for the disintegration of U—238 produces Th-234. What other nuclide is produced? ’3 B‘ C) 3He D) positron E) neutron 5 . If In-116 undergoes [3' emission, what other nuclide is produced? (:1) Cd—115 m) B Sn-116 \vo / o C) Sb—120 . n J) A T Q D) Ag—llZ W E) Cd—116 6. The most ionizing radiation is of what type? g?) alpha beta C) gamma D) electron E) neutron ' E) 7. The nuclide AH lies above the band of stability. This nuclide is likely to undergo A) positron emission. B) orbital electron capture. C) 6' emission. proton emission. @ oc emission. 8. Predict w fthe following is most mfg \’ Q Ne—20 9m i0 n i > "\ “are” ) (3) ~~>%‘i{>)l‘1b‘(‘ Po—210 —-/' C) Fr—223 a 8')? ,l‘sbn D) Kr-87 aabp S‘lo E) Sc—43 “(J—a )4 “‘11 n 9. Elements with an odd number of protons and neutrons A) have a magic number of protons or neutrons. never undergo 0c emission. C? are usually unstable. ) always have a proton to neutron ratio of about one. E) are usually stable. 10. The bombardment of 75 As by a deuteron, 2H, forms a proton and an isotope which has a mass number and an atomic number of . . — —- ' g“ 1' 1‘0 A) 75,32 7 . V v \ . . B) 75,33 gsbfi Jr \\7\ 9 \Q J“ 33 BS 73, 32 76, 33 74, 34 11. Predict the type of radioactive decay the He-6 would undergo? A ., alpha (0 » r1 6’ beta ; 5A9 V ._ . C) positron 0 " D) electron capture E) C and D Predict the type of radioactive decay the Ni—56 would undergo? A) alpha ~— (613 B) beta - P i1 u 18 Mt 2e C) positron V) 7 D electron capture E) t C and D 12. Predict which of the follovbmg isotopes of Lanthanum is most stable. 138L . . ~ 139 a 5—] 6‘ 7 B) La g‘pw NHL \ C C) 140in x3; 8o D) 137La E) Cannot be determined 13. If a nuclide lies below the band of stability, it should decay by A) B" particle emission. B) neutron emission. C) positron emission. orbital e— capture. £5 Both C and D. 14. Rate the penetrating power of the following particles from most penetrating to least penetrating: 0t particle, y radiation, B particle. A) 0t particle > y radiation > B particle B) B particle > y radiation > 0t particle C y radiation > Cc particle > B particle {.12}? y radiation > B particle > or particle B particle > 0c particle > y 15. The nuclear binding energy for lithium—7 is the energy released in the nuclear reaction 71H—>7Li @) 31H+4n—>7Li C) 6Li+n—>7Li @31H+4B—97Li E) 31H+7n—>7Li 16. The equation 41H —> 4He + 28* A) fission. B) electron capture. C) the decay of a proton. the binding energy of He. fusion. 17. What is the rate law and the molecularity for the following elementary process: C10 + CF; —9 O + CFZCl A) k[C10] [CF2C1], bimolecular k[O] [CFZ], unimolecular k[C10] [CFz], bimolecular k[C10] [CFZCl], trimolecular E) k[O][CF2C1], unimolecular 18. Predict which of the followgig nuclides would you expect to be radioactive? A) 206Pb 237Np 93” \ ‘1 D) 2"Ne ‘10 L08 g Ngne of the above J \ \ Part II. Show work to receive full or partial credit. 19. Correct this one. The rate law for the overall reaction of the mechanism below is C12(g) ca}. Mg) / K1, fast C1(g) + CO(g)/¢> OGCICg) K2. fast poeifig) 4; (mg) ~—> COC12(g) k3, slow . V; ‘5/ A) mt€=k3 K1°'5K2[CO][C121‘-5 [Cl-1: Lug M rate = k3[COCl][C12] C rate 2 k3 K1 D) rate = k3 K105 K2[C()1]5[C12]0'5 0 C521: {@963 E) rate = k3[COCl][C12] - I a 1E? / QNQgECOJLQLZk/EQB k2} 9% <2 “\«V 20. In the 232Th decay series, the product is 4 alpha and 6 beta 6 alpha and 4 beta %. 3 alpha and 3 beta Cannot be determined A) ® No “7/ 0300 \4: 5t Pb. How many 0L and [3 particles must be emitted? 21. A 9.9—g sample of iodine—131 is stored for exactly 2 weeks. If the decay constant is 0.0861-day‘1, what mass of the isotope remains? A B) ) D) E) 6.7 g 3.0 g 0.060 g 0.62 g 8.3 g 22. Estimate the activity of a 1.5-Ci radium-226 source, t“; = 1.60 x 103 y, after 2000 years have passed. ‘ A) 1.5 Ci B) 0.20 Ci é/ @ 0.63 Ci D) 1.2 Ci E) 0.45 Ci MAC '7: N0 1m, 23. A sample of a wood carving from an archaeological dig gave 20,400 disintegrations per gram of carbon per day. A 1.00—g sample of carbon from a modern source gave 22,080 disintegrations per day. If the decay constant of carbon-14 is 1.2 x 10—4-y_1, what is the age of the woo ‘7 A) - B) C) D) E) 660 y 1700 y 290 y 8300 y 6.2 x 104 y z 7.6 Pvt"; 30 [4. Calculate the nuclear binding energy of 1 mole of iron—56. 56Fe, 55.9349 u; n, 1.0087 u; and p, 1.00713. -159 x10;kJ 13m 2 SS”. ‘9) 54% —~ 24 (L 06789 B) 3:33:34ij a $005351} * 10 tastiest —: —o.§28>9 1:? tbs/t8” 5” A WQMO‘O H [5. Calculate the energy change when one 235U nucleus undergoes the fission reaction 235U + n —> 142Ba + 92Kr + Zn The masses needed are 235U, 235.04 u; mBa, 141.92 u; 92Kr, 91.92 u; 11, 1.0087 u. +2.9 x 10‘11 J £35 —2.9 x 10‘11 J C) —1.7 x 10'10 J D) +1.8x10—‘0J E) —3.2x10—28J . ' ,5 2i, . .A Am: a<twm+19t9>+elk-9: “£3,704 7 m3 1 4%0 VB/x—i::fl\j\(, : _. 1 atm = 760 Torr 2.54 cm = 1.00 in = 101,325 Pa 1 1b = 453.6 g 1 u = 1.6605 x10'27 kg 1 Ci: 3.7 x1010 Bq =1. Conversions: 4924 x 10'10 J = 931.5 MeV Constants: R = 8.3145 J/rnol K = 0.08206 L atm/ mol K h = 6.626 )(10‘34 J s Spectrochemical Series CN'>CO>fl02‘>en>NH3>SCN>H20>QNO‘>ox2'>OH'>F>§CN'>Cl‘>Br‘>I' Equations: 0. 2569 .0592 AGO : —nFE:ell : _nFEcell Ecoell = ¥ln Ker] Ecell : Ecoell _ 0 n log Q 0 0 O O o AG = AH° —TAS AG = AG + RTan AG 2 —RTln Keq EM, = Eceu ——an nF Ea I t o — o _ RT — -MM =mass 1n£=AH i_i sze RT Even—[E]an (up) K1 R T1 T2 AB = 11C / A. AE =An‘1c2 : —- Ecell : Ered + on (first order) (zero order) (second order) In [A]t=1n [A]o —- kt t1/2 = (1n / k Magic Numbers of Nucleons Neutron number. N l50-— 2, 8, 20, 28, 50, 82 I40 "“ no _. Alpha emission . k) .y 120— a) Q 110— ‘ , I Belt 01 stability .5 mow ‘- 90— 80“ . 70__ l'lememissinn hl)‘ I Positron emission 501” and clcctmn capture 40- :3 '2' t ;: / 1V1'31 30*“ 3/ 3()'— /' 10 “/ "1.15.1 ...... .._1........J_W.WL ........ .... .J (l 0 10 30 30 40 SO (70 70 80 Promn number. 90 100 [Alt = [A]o - kt t1/2 = [AL/2k NA = 6.022 x 1023 atoms /m61 Cp (H20) = 4.184 J / g °C F = 96,485 C / mol e' 101.325 J =1L atm Ica1=4.184J 1 Bq = 1 disintegration / s = nuclei 1 MeV = 1.6022 x 10'13 J d(H20) = 1.00 g / mL Kw =10 xlO'14 c = 2.9979 x108 m/ s 1A1" = [A10'1+ kt t1/2 = 1 /(k[Alo) Activity = )1. N where N = # of nuclei present Red Violet Blue ‘ Green ...
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practice_final_a_key - Chemistry 26 Practice Final December...

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