CHEN1211Spring08Test1

CHEN1211Spring08Test1 - AN 95am. KEY CHEN 1211 Midterm Exam...

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Unformatted text preview: AN 95am. KEY CHEN 1211 Midterm Exam 1 Wednesday February 20, 2008 Instructor: Prof. Doug Gin This is a closed book exam. There should be a total of 8 pages to this exam booklet including the cover page, a list of constants and conversion factors / salt solubility table, a page of equations, and a copy of the Periodic Table. There are 17 questions in this exam worth a total of 100 pts. There are five 8 pt questions and twelve 5 pt questions. Answer all questions on the separate Scantron answer sheet by darkening in the proper bubble with a number 2 pencil. If you change your answer, be sure to thoroughly erase the undesired mark. Make sure to write and bubble in your name and SID number on your Scantron answer sheet. Read the questions carefully. Note the point value of each-question and budget your time accordingly. Feel free to use the front and back of your exam booklet pages for scratch paper. The exam booklet is not to be handed in. Any answers not included on the Scantron answer sheet will not be counted. You have a maximum of 1.5 hours to complete this exam (7:30 -—9:00 PM) GOOD LUCK! By taking this exam, you agree to abide by the CU Boulder Honor Code for this test, as stated below: ‘ Honor Code Agreement: "On my honor as a University of Colorado at Boulder student, I have neither received nor given unauthorized assistance on this wor ." Additional restrictions: (1) Please turn off all cellular phones and other related wireless communication devices. The use of such communication devices is prohibited during the exam. (2) Calculators are allowed in this exam, but devices capable of storing more information such as PDA's, laptop computers, etc. are not permitted. , (3) The use of headphone audio devices capable of data storage such as MP3, CD, and cassette players are also not permitted during the exam. Any student found using such restricted devices during the exam will considered to be cheating and will be reported to the CU Boulder Honor Code Council for punitive action, as outlined in the class policies. (1) A 0.107 M aqueous hydrochloric acid solution was used to analyze an aqueous calcium hydroxide solution of unknown concentration. If 37.6 mL of the unknown calcium hydroxide solution was neutralized by 43.8 mL of the stock hydrochloric acid solution, what is the molarity of the calcium hydroxide solution? (5 pts) 0.0623 M CACoH), + i-HCJ --? Canal} 4' git-(3,0 I 0.127 M 533 3234 M 919.533.1wwl.2;521zr§HG CW). 1 1 VVVVVVVVV 1 (e) 0:0107M x ’ 1-H“ ans-£1164 .0.C>?a7é,L.Cb@tQ; a. 0:21.33. M cacoa), (2) Dimethylhydrazine,which has the molecular formula C2H8N2, was used as a fuel for the original Apollo lunar descent module. It was reacted with the oxidant N204 to produce H20, N2, and C02 in an extremely energetic reaction. What are the coefficients in the balanced reaction, respectively? (8 pts) (D @ C‘D‘ @ LCszNz + £th04 > EH20 + _C.Nz + Dem 51%WWTTM '-. (a) 1, 1, 1, 2, 2 . __.~ g; 2, 1, 6, 4, 2 9' DE) afls_+ 1, 2, 4, 3, 2 .O 9:; a ‘ )v u a w I- 2, 2, 5, 4, 6 N: ’ $0 3+3<3>wac (e) 1, 2, 3, 4, 2 ’ == 3., CD1 41%;: 18: +35 ==— ++a<al I. I‘ve: V4- =3... (3) The following unbalanced redox reacti n is performed in basic aqueous solution: L536 a3 32." Zn .1le s) + Home > 22022741) + NH3<aq> (4% GE) (“'3 ' 5?} emu afi 82?: IQ What are the correct coefficrents for OH‘, n, N03‘, ZnOz —, N 3, and H20, respective y, in the balanced reaction equation? (8 pts) (D E“— fi; 0‘, 6f” Mgpm 1" MRS humewa 63 o @ 79 49 1’ 4’ 19 2 4 ZAO e 4W (b) 5, 4, 1, 4, 1, 7 , --' A C: (c) 7. 4. 2. 4, 2. 2 mama a» BL: sum are" (d) 1, 1, 1, 1, 2, 1 @ BM" * W ’ “f a: (e) 5. 4. 2, 4, 2, 7 a , gig,“ ¥oae+ izfiwoa % 16.2w. wig w r g @ 3.24.4 0’22. 441;. w/ 114;. 20119 +1 5.2.0.1» gym? -7 izzOfS+Lm§ @135 2 (4) Which is the win the reaction described in Question 3 above? (5 pts) (a) OH- 8 o (b) Zn go a ————? ~> {3&3 (c) 211022‘ are» c-a) NH3 .. ’ N03 Lafbefig D ALEX)» (5) What is the oxidation number of P in HZPOZ‘ ? (5 pts) +1 "l 3" 9-633 4 >6) + .Qf-u) (b) —1 I 0 E31; :33 A =’ a + x ~¢+ (6) +5 :q Ye! “[+4’A =—- 6) (6) 239U can be oxidized to form an atomic ion with a charge of +4. How many electrons are . . . 9 ___,. present 1n this cation. (5 pts) {'3qu “A9 a & Pea 50 Ho gr” HAVE gag, U: k... (a) 235 (MM Mj mam ‘ 4 .. Etc» 323 » “93‘! u@ “*5 4.6;" , $5 (Mil-(As. (a) 88 V “‘9‘ (5):» Ram “Mb ‘33 e. e) 96 Cxl—(y , (7) When 0.210 g of an organic compound containing only C and H was burned, 0.660 g of C02 was produced. What is the molecular formula of the compound if it was analyzed by mass spectrometry to have a molecular weight of 42.1 g/mol? (8 pts) a,me m b (g Cxl—L, + ,o> ——-=> _CO,, +~ W “:9 "4 W , - «£7. Q a C H . m“ ' . . Fawn W H 5 8 Cir.“ ~- Mew aces: , www» fit:va (c) C3H8 atka C, 5.. Lg; rm“ ,t 1.3% ‘5’ [56m pc— d C4H3 m 0.340%, exit, 3 Elk/Imogen, Hue as}. (W S C3H6 . Mfa' == “WW”: ¢ ’3""M°H i'g‘fi ‘2» (Mac 36— Ms W C.u,;rw> min—3% in W. / I“ >6E a o ‘ g ‘ 4 ‘ =3 H a (. a_ ll m... H... 421w» ‘ .méa; 3 ° 7% 3.. ’7 o u :3, OWm-wmnma M 2;): g CXHYW make @950 M a“? ( n unknown solid was found at an industrial‘waste’fiump site, and was determined 5y chemical analysis to be composed of 26.6% by weight K; 35.4% by weight Cr; and 38.0% by weight 0. Given these data, what is the empiricalformula of this unknown solid compound? (8pts) Wis t (00.0% W)“ BY (£6379 3-? 36.Q% () KCrO gate (4 / k; _ ‘0 (g) K8034 W =o.e2c>z-4K $.33... (00‘0fi‘rflThL. (C) K3Cf20 36‘ 4 en Mme: G~ (d KCrO _ WW, M w mg K2Cr2207 “ #8:” 51- w O‘QS’O O .' . (3.212%‘69e £23 LMWQWW :: . ear/«GK <3 ' “5"“5‘6’9‘ egtarféoewmo ’1 .2 (41cm 035 (9) When aluminum dissolves in aqueous sodium hydroxide solution, the reaction is: '2_NaOH + iAl + 2H20 —-—> 2 NaA102 + 1H2 If 84.1 g of sodium hydroxide and 51.0 g of aluminum react in the presence of excess water, what is the mass of hydrogen gas produced, assuming complete reaction? (8 pts) 1:1th HHI‘TMé: {2mm- 0F WE:- Wa FIEM'.‘ Cl-laOQW—ka’ml ‘ 1.90 5.71: AuNL— Hob Nam-l = §gjsgwlfism "32.7%:‘39‘ = ;.to«emot€ 0) 6.00 (d) 0.951gg AWL" M" A‘ = 5371,2031: M: 1. 2% m M (e) 3.31 g “W aéfls'ts‘laAl 9M NAOH “5M JM)‘ 3. A\ [5 LAN kkwm’: 51.03 All 9%! I}. +_ 9-0539] 2.3,). :: $.77;le F (00% aéfii'lg’afil 2 ,Al mag , ' m (10) Which of the following sets of quantum numbers for electrons is NOT allowed? (5 pts) a n=2,l=1, m,=—1 “‘2 Winn; 4‘0)‘:3n"(l") & n=2,l=1,ml=2 Msaasmz; (c) n=1,l=0,m1=0 ‘emlfllléf (d) n=3,l=2, m1=-1 ml =o,1l,i‘a.ui‘,( (e) n=5,l=3,m1=—2 / ~ (11) What is the number of unpaired electrons in the Ru3+ ion? (5 pts) XMLQ’ Ammm pm? EM Art-om ; 53344 6’ E§t~1§SI4d7 (a) 1 I P ' (AéSOHEb neon RT canon: Eb; g T H: LoSfi s Emmawe Beamg 2/5 smsw’ew c ’ V a d 4 FOWiNén ;—gHE:: apteb I 5 r as t g, 1 _ a D01 p «w “w r. w m , Hafifi 61/ “n f 3PM) (12) A very unstable atomic ion with a charge of —1 was made in a particle accelerator. It has the following electron configuration. What is the identity of this ion? (5 pts) c s11— * ' “0‘5" HAxla t chew; as” To BE... (d) Cul- HQ NW“ ATTDH STA‘tfir '17:: 12>. (6) Bl- ELEHW ’ Mno‘ " For questions 13—15, consider the following atoms: (a) Cs (b) Ba (c) S (d) F (e) Ne (13) Which has the largest radius? (5 ptS) @ Mac—£57“ n FORM GW' 3% (14) Which has the highest first ionization energy? (5 pts) @ {#65 VW .— Nwafit aka & WF‘bl‘w -r (15) Which has the greatest electron affinity? (5 pts) RM” To Mme W“— '3 Sc, Fret-402:1“ EN A» +196 [fies—193’ng mFléa warm was . 167% ear-r0 W matte (16) In the followmg list of molecules, which has the most polar bold-faced covalent bond as: Ha containing H? (5 pts) (a) H—H 0 “5 “1‘55"” EH at: Au... 0mm; W 83)) 3:80:11: BDNbE> “m H m HE. S no LEerffig “‘55:. 3 ii 3:31:12 :39 0 15 450W R. “£— HIé-téPST‘ N Paw—amt: 716$ , «an MGF’A NDBIEQAg (17) Of the three electronic transitions detailed below, which of thenyinvolve emission of energy? (5 pts) K > as an E: F5 0) He atom: 1512p1 —> He atom: ls12s1 K, grab“ i WCE 235" (ii) Fe atom: [Ar] 3d64s2 ——> Fe atom: [Ar] 3d64s14 1 e- 41, >45 m E. (iii) Hatom: 2p1 —> Hatom: 23K aggwgm‘; ) Aagglfi.eé§/LM (a) tap E325 m E: Fee a w () Eh?) MUN. use. #90» E W (gal c 111 > (d) (i) and (iii) (e) (ii) and (iii) ...
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CHEN1211Spring08Test1 - AN 95am. KEY CHEN 1211 Midterm Exam...

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