Practice 2 Exam Key

Practice 2 Exam Key - Key Lab Sec TA Lab day/time Andreas...

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Unformatted text preview: Key Lab Sec. # ; TA: ; Lab day/time: Andreas Toupadakis, Ph.D. Winter 2006 CHEMISTRY 2A Section B EXAM 2 Multiple Choice (circle one) Instructions: CLOSED BOOK EXAM! No books, notes, or additional scrap paper ‘___————‘ are permitted. All information required is contained on the exam. 2- a b C d (9 Place all work in the space provided. If you require additional space, 3_ @ b c d 6 use the back of the exam. A scientific calculator may be used (if it is a 4. a @ C d e programmable calculator, its memory must be cleared before the exam). Sharing of calculators 15 not allowed. (1) Read each question carefully (20 problems, 8 pages). 7. a e (2) For Parts I and 11, there is no partial credit given and only answers 8. a © c d e marked on this cover page will be graded. 9. a © 0 d e (3) The last page contains a periodic table and some useful information. You may remove it for easy access. (4) If you finish early, RECHECK YOUR ANSWERS! 10. a b Q) d e U.C. Davis is an Honor Institution Possible Points # 1—9 # 10-15 (6 points each) # 16—20 Total Score (100) (4 points each) I 0-15 total points: (28 points) WINTER 2006 MIDERM 2 (Page 2 of 8) Part 1: Multiple Choice, Concepts (4 points each) Select the best answer (one answer) and enter your choice on the cover sheet — No partial credit 1. Which of the following solutions has the lowest concentration of sulfate ion? a. 0.1 M A12(SO4)3 b. 0.2 M MgSO4 c. 0.3 M LigSO4 d 0.4 M K2804 e. 0.5 M CuSO4 2 . Complete the equation and indicate if a precipitate forms: Na+ + C1' + NO3' + K+ —> a. NaCl(s) + NO3' + K+ b. NaNO3(s) + K+ + Cl- c. KCl(s) + Na+ + N03' (1. KNO3(s) + Na+ + Cl' e. no reaction 3. Gold does not react with either nitric acid or hydrochloric acid but with a combination of both called aqua regia. Identify the reducing agent in the following equation: Au(s) + 4 H+ + N03“ + 4 Cl‘ —9 [AuCl4]‘ + 2 H20 + NO(g) . Au . H+ .NO3' . Cl" .The reaction is not a redox reaction. mQOUW 4. The energy of molecules of a gas: a. is dependent on concentration is distributed over a wide range at constant temperature is the same for all molecules at constant temperature increases with a decrease in temperature 9995‘ increases with an increase in pressure WINTER 2006 MIDERM 2 (Page 3 of 8) 5. If someone were to light a cigar at one end of a closed room, persons at the other end of the room might soon perceive an odor due to gaseous emissions from the cigar. Such a phenomenon is an example of: a. monometry b. ideality c, effusion d. diffusion e. barometry 6. Gases tend to behave ideally at a. low temperature and low pressure b. low temperature and high pressure c. high temperature and low pressure d. high temperature and high pressure e. gases always behave ideally 7. When an electron goes from a high energy state to a low one, what occurs? a. another electron goes from a low energy state to a high one b. the atom moves faster c. light is given off d. this process is not possible e. none of these answers 8. What is an acceptable value for the missing quantum number? n = 4, l = 2, m1 = 0, m3 = ? a. 0 b. 1/2 c. l d. 2 e. 3/2 9. [Kr] 5524d105p5 is the electronic configuration of: . Te . I . Br . At a b c d e none of these WINTER 2006 MIDERM 2 (Page 4 of 8) 10. 11. 12. Part 11: Multiple Choice, Short Calculations (6 points each) Select the best answer (one answer) and enter your choice on the cover sheet — No partial credit When the following equation is completed and balanced for the reaction in acidic solution, what is the proper coefficient for H+? Zn(s) + Cr2072'(aq) —9 Zn2+(aq) + Cr2+(aq) :- 3: Zn ——>zv3* OXiduX-‘xom C: 14 001011, ——> Cv2+ Y‘CdUCl-iom ZS d. 11 va _> Zm1+ Jc 1-6— éotclA quQ‘Hom 6- 7 CY10¥1— + \L\ Hip + 8e” ___> QCvl++1 Hzozonovsazd by I, \MDSC 1" (huvae __> 7. 1+ p— L‘\ZV‘ 1’ Ll V; +,g;‘e 2+ {gechroms 0Y6 CT101 +\HP\ £846 -—->le +1\-\20 baa-mad + +1010 The neutralization of 25.0 mL of 0.24 M HCl requires 5.0 mL of NaOH. What is the molarity of the NaOH solution? a. 0.6M (15.0wL €02“)CO.ZL‘ MHC'O 36.0 quo-e \XCQ L‘Zm t CVzO’xf' -\— \m—KJr -——> HZml’c Jr ZACVl b. iii; MUJ‘VM‘ZGHOM weom : mwot Hw‘: “We! 0H :1' 0'048M and because mwto—Q 00,0": wwog RU; umd e. 1.2M WWW/e OH- " VV‘VMO'e NGOH coo VV‘wm-Q \ACQ : Uuuuo‘e NOOH :0 W‘Wso-e NaOH : 6.0 0““ g‘m’fly Ceowmr Mom/(so wL Neon) :. Lil/M To increase the volume of a fixed amount of gas from 100 cm3 to 200 cm3: a. increase the temperature from 25.0 to 50.0 0C at constant pressure b. increase the pressure from 1.00 to 2.00 atm at constant temperature ../) l g 1V 0. reduce the temperature from 400 K to 200 K at constant pressure V d. reduce the pressure from 608 mm Hg to 0.40 atm at constant temperature e. increase the temperature from 400 K to 600 K at constant pressure P V t; V\- Q T. 00 lewpevufiwe WWcl- be in mew. b} \lo—Quwe wiZQ decrease C) Vofluwe wig-Q decrease d\ Pi = 609 WM “'0 lo PezOLtO <1ch 6*“ pvesgure lo—ecoouet W164 3., Wad” douWY. e) \lo-eflwe lvva—eut-es loo+ lg mot domd, WINTER 2006 MIDERM 2 (Page 5 of 8) 13. Of the following gases, the one with the greatest density at STP is: a. CH4 b. NH3 d: PM Hoe one wi-\\A fiveo’ced moflfuv— :- E9 R-T masq, AA. - 2 e. He Cl—\L\2\6) NH3:\1)N€,:10,l-\121,\-\(1L\ 14. A television signal has a wavelength of 10.0 km. What is its frequency in kilohertz? a. 30.0 1 L b. 3.00x104 3t: lO.o km ) V: - ~ H7. c. 3.00x107 3 ..: d. 3.33x10'7 sz.’) A? V: c ___ $00on vw§ _ 2 e. 3.33x10-2 7\ ('O'Okwl<|000 _w‘_‘ _. L‘ ’l L‘ w -—3.00X\O § :3.OOX‘Q “Z: : 30 O lr< \'\7_ 15. Calculate the deBroglie wavelength of a ball of mass 125, grams and velocity 90, m/s. a. 0.59m b. 5.9x10-31m c. 5.9X10'35m I) : __l/_‘___ d. 590 m m ' U e. 1.7x1034m 7. -3 -3 .. l/\:6.616x(o “jig :6.616xl0 Ll Loam/(Is § -3 - =6.69.GXIO H k3 ml: VV'l : \15.3 : O.('l§ [<3 U ’5 QC. \Mg" WINTER 2006 MIDERM 2 (Page 6 of 8) Part III: (28 points) Please show All work for calculations — Partial credit may be given 16. Complete and balance the following equation for the reaction in basic solution. To receive credit you must use the Half-Reaction method, show the oxidation and reduction half equations and label them, Show both equations balanced by mass and by charge, show how you go from acidic medium to basic medium and finally show the simplified overall equation. Br2 + Mn2+ —> MnOz + Br' 529* Mull ”9 Mn01 oxidant-tom 8Y1 _“> BY.— Yedochovx + ,/ , SMml -\— 1H“) ——> Mmoz + [ll-6% Bold/x lQOgumLQd by we“ 1’ Chev-be. Pl 8Y1, *%4 —"> lBY Egon! # e—ZQC'l‘YOVtS “ 2+ , Mm +1sz0+th ——>/\Am01+qu++18v W + qua” +LIOH' J‘mto ll—lzo 1+ - — ”5+3 [Vim -\— 8Y3. +H0\\ ——> MmO'L + 1H10 + 19% 17. A piece of iron wire weighing 1.63 g is converted to Fe2+(aq) and requires 21.9 mL of KMnO4 solution for its titration. What is the molarity of the KMnO4 solution? The balanced equation for the reaction occurring during the titration is: 5Fe(s) + 2Mn04'(aq) + 16 H+(aq) —> 5Fe2+(aq) + 2Mn2+(aq) + 8H20 [lP’c ”’2 ([63 06 F€><Lfgigé> I: 0.07.91 Move Fe 219.9. mwo—e Fe A“ 4-’> (19.1 mwo-e Cc) (1 Mun-e NMOL" : H.1l wwoae MWOL" s tumor Fe ‘Pl (“.1 wwwe vao‘t’){4 wwoe kMV‘OH ) f— H‘1 WWW’e LCM“OL1 ’l \M £ vi0 — lot ”'1 ”We LCMWL' , 25031.1 m n ‘ 9.1.9 ML kNmOL‘ gee». ' ' 2%» 779* 3 pl 739): WINTER 2006 MIDERM 2 (Page 7 of 8) 18. When 8.21 L of C3H8(g) burn in oxygen, how many liters of oxygen are consumed? All gas volumes are measured at the same temperature and pressure. Assume that the combustion is complete and the only products from the reaction are carbon dioxide and water. CSH8(3l +501C'0la3C01(33-¥ L\\'\10 (a) Vtc=.\xe):<a.1n_ ) V(013:7_L VCOz) , S A), V(o¢):s-V((3H8) ‘5 =SXQ.’).\L \/ ((3 H 8) 4— 19. Showing the x, y, z axes, draw the following orbitals: s, px and dyz. 8 Z Cpl ‘ 20. Give the electron configuration for the anion Br ' (spdf condensed notation) and oxygen atom (orbital diagram) using the periodic table. Electron configuration of Br ': ls2 “351 if 3S1 $96 Scullo L\§1 LIPG Electron configuration of the oxygen atom: ® GD IS ’13 ”l? WINTER 2006 MIDERM 2 (Page 8 0f 8) Periodic Table l 3 [[1 H _. ,, LUVNJ 109794 4100297312, .1 Be 0 7 91941901218 1031311 12.95127 14.00574 159994 31999403 213179? 11 12 13 14 15 1e. 17 Na Mg Al S1 C1 1' ' 21999779 243959 269915.119 239755 30975791 52.0111} 15.4527 .19 949 k ‘u 23 29 1 Ni Cu As Br 551345 5119332911 3.9934 97.545 9529 99723 7291 7.992199 73.99 79994 93119 49 97 4a 99 59 52 Ru Rh 1’ Ag C‘d In '11 T1: 10107 1929959 99.92 191719112 11113191133119 12179-9 12760 12999447 131: 7c. 77 79 m _ )5 [r 11 1 g Bi Po 199.21 2127 55 m9 21351211175 297.2 208999311 (2993 1011 109 H A I l J Solubility rules: Compounds that are soluble 0r mostly soluble 0 Group 1, NH4+, chlorates, acetates, nitrates o Halides (except Pb2+, Ag, and Hg22+) o Sulfates (except Sr2+, Ba2+, Pb2+, and Hg22+) Compounds that are insoluble o Hydroxides, sulfides (except above rule, and sulfides of group 2) o Carbonates phosphates, chromates (except above rules) Some useful equations and data: PLEASE NOTE: Important values and equations required for calculations are given with the respective problem. The following may or may not be of any use. n (moles) 2 fig— molar mass (g/mol) NA=6.022x1023 =. ' 1J=1kgm2s2=1Nm P1099: P1 + P2 + ‘ . R = 0.082 L atm mol'lK1 c=3.00x108ms' ...
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