Toupa exam1 S06 key

Toupa exam1 S06 key - Student ID Number K 6 ‘L Lab Sec. #...

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Unformatted text preview: Student ID Number K 6 ‘L Lab Sec. # ; TA: Andreas Toupadakis, Ph.D. CHEMISTRY 2B Section B Good luck © EXAM 1 Instructions: CLOSED BOOK EXAM! No books, notes, or additional scrap paper are permitted. All information required is contained on the exam. Place all work in the space provided. If you require additional space, use the back of the exam. A scientific calculator may be used (if it is a programmable calculator, its memory must be cleared before the exam). (1) Read each question carefully (20 problems, 10 pages). (2) For Parts I and II, there is no partial credit given and only answers marked on this cover page will be graded. (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! U.C. Davis is an Honor Institution Possible Points # 1—9 (4 points each) # 10-15 (6 points each) # 16-20 (28 points) Total Score (100) ; Lab day/time: Spring 2006 Multi le Choice (circle one) I 0-15 total points: Name EXAM I (Page 2 of 10) Part 1: Multiple Choice, Concepts (4 points each) Select the best answer and enter your choice on the cover sheet — N0 partial credit 1. Objects can possess energy as: (a) Endothermic energy (b) Potential energy (c) Kinetic energy A. (a) only. B. (b) only. C. (c) only. D. (a) and (c). E. (b) and (c). 2. For a given process at constant pressure, AH is negative. This means that the process is: endothermic exothermic equithermic a state function energy P130575?” Which one of the following is an exothermic process? La) ice melting water evaporating boiling soup condensation of water vapor ammonium thiocyanate and barium hydroxide are mixed at 25°C: the temperature drops. mpow> 4. Which of the following has the highest boiling point? . N2 Br; H2 C12 02 muow> Name EXAM I (Page 3 of 10) 5. Large intermolecular forces in a substance are manifested by: A. low vapor pressure B. high boiling point C. high heats of fusion and vaporization D. high critical temperatures and pressures E. all of the above 6. Which of the following is not a type of solid? ionic molecular supercritical metallic covalent-network 31.5.0??? 7. A dilute solution was made by dissolving sugar in water. The vapor pressure lowering AP for the water is given by the equation: A. = ' Xsugar ' Powater 13- AP = + Xsugar' POwater C. AP 2 ' Xwater' Powater D. Z + Xwater ' P0water 13- AP = " Xsugar' Posugar 8. The phenomenon used to differentiate colloids and true solutions is called the ---—- effect. A. van’t Hoff B. Tyndall C. Raoult D. Osmotic E. Henry 9. Which one of the following concentration units varies with temperature? molarity mass percent A. B. C. mole fraction D. molality E. all of the above Name EXAM I (Page 4 of 10) Part 11: Multiple Choice, Short Calculations (6 points each) Select the best answer and enter your choice on the cover sheet — N0 partial credit 10. Consider the reaction: 2 Al(s) + Fe203(s) —> A1203(s) + 2 Fe(s) lfAHOf for Fe203(s) is -826 kJ/mol and AH"f for A1203(s) is -1676 kJ/mol, then AH0 for this reaction is equal to: A. -622 k] B. +984kJ o 0 o C. -1168kJ AH -,-, 2 m? 1) Ha (pvoautfl « E inY be (Yeodcmis) D. —241kJ hm E. -850 kJ [Pea-03631 : “83-6 Vj/wm—é [EH2 {($51,036)} 2: 4616 Lzy/m/e DH; [I-Wm’) 2 DH; C9130 =0 AHOY“ :[it woi Afiaosmx («l676L> + :2 we (360»ch “Kt.sz “love v [a We Man (our/w) + wa 9’10“me We») : ~\(>16 Lay-(«8'16 ["30 11. Assuming that the combustion of hydrogen gas provides three times as much energy per gram as gasoline, calculate the volume of liquid H2 (density = 0.0710 g/mL) required to furnish the energy contained in 80.0 L of gasoline (density = 0.740 g/mL). A. 458L mags O’f 80.0 LaoSo’eflnfl B. 277L C. 563L ‘ ooo auto 3 D. 285L 90.0/t/yiixw— 1 E.122L , ’Sq’ Go a ’L}! W WOSS of 141(4) heeded: €9,100a/3 :Mftoo a l 40 volume 04: We) Madaggggm @ Name EXAMI (Page 5 of 10) 12. The vapor pressure of water at 25°C is 23.8 torr, and the heat of vaporization of water at 25°C is 43.9 kJ/mol. The vapor pressure of water at 50°C is: A. 56.7 torr B. 32.7 torr X P; DH vap ( \ C. 48.4 torr V\ ‘- ‘———"' -~——— ~ D. 93.7 torr P. Q ’T. T1, E. 39.2 torr 9:138 em 3 ’17:1s+113:198k (37,: ’5 {*ovv) ’71; go+g13 3.31)) K l QiAVOP: VI/WO’C \ Q: jWO‘e’iK— by P7, _ H3,‘5003~w0{" < l I 1A8 835m ywoe‘ik“ 1%6k 373k w e 13. Nickel has a face-centered cubic unit cell with a length of 3.524x10‘8 cm along an edge. The density of nickel in g/cm3 is: A. 9.058 g/cm3 CC Uh.\_ “£6 ‘ S B. 8.909 g/cm: A ‘ (.Owi'ounS Ll atom . C. 5.703 g/cm . D. 3.639g/cm3 The VO‘ZUVM‘C 04' 0 Cubic, Uvfil— (w \3 ; E. 2.759 g/cm3 2 O V:~’6 00 V:Cg_61q XIO’GCw3g ‘ -13 2 The was; 616 4. mom: " “376 X'O 9"” 6 c3 ’3_w« 6 v7.3 d (mated) =1 d (Umi’r (ea) :. WOQQIV‘ UM”. “U : Voguwlc o4 UMi¥C€ZI€ -23 ‘. 6 l0 9.909 as» L4.g46>uo‘ UM Name EXAM I (Page 6 of 10) 14. A certain soft drink is bottled so that a bottle at 25°C contains C02 gas at a pressure of 5.0 atm over the liquid. Assuming that the partial pressure of C02 in the atmosphere is 4.0x10'4 atm, find out how many times the equilibrium concentration of C02 in the soda is reduced after the bottle is opened. The Henry’s law constant for CO2 in aqueous solution is 3.1x10'2 mol / (L - atm) at 25°C. A. 18000 times B. 5t'mes C. 13000times l’\\€VW‘\/3< COW ‘ C30; 1 pans D. 178 times E. 96 times Cflosea \ooHa our eqogabmw gate. (401 ’3 Pcoi :ZthO'L ATE—£150 01%: 0/6 /\A JL \Moé —\—\ Cum, 2-. PCOL:Z.\X\O Lu x (4.0240 Ow: Limo M C(fiosed /CQP€V\‘€A I 0"6/l.'l)<lo‘§ I (7,000 /l 15. Chrisa who is a biologist is trying to identify a human hormone that controls metabolism by determining its molar mass. A sample weighing 0.546 g was dissolved in 15.0 g benzene, and the freezing-point depression was determined to be 0.24000 If Kf for benzene is 5.120C'kg-mol'l the molar mass of the hormone is: A. 776g/mol <3“:st 05146 g lxioirw. _ _ ._____________,__ B- 568g/mol Mogav M099 — .. 2 C. 394g/mol W\O«€ZS , woaees D. 285 g/mol E.195g/mol heed {—0 ngd Mow MACH/xv mofig Off, 0.9H6 8 0’5 l/\OYW\OV\€. MO‘éO/gil'y O’fi lflothov‘g: m : _: : q‘égx‘O-L \MO-Q lf\OYw0v\{, to: SJQXikaw-me" k3 benzene, 5 wo—e levwovH’ 0v L[~69><‘O- 0v in 190 3 0’: lo-€V\‘C€v\-C ‘3 bfnvau’. —H EUQYE WCU be Hiégx‘o~9fl\g:4.OthO woe lewuone. 3., M Z O$L|6 3/7.oqxuo’ H we'd Name EXAM I (Page 7 of 10) Part 111 Please show all work for calculations — Partial credit may be given (6 Pts) 16. a. What is the expected integer value of i in a very dilute solution of Fe(NH4)2(SO4)2? .L- 1 C6 (Ni-\Id'LLSOI-tli &% Fe +(aq) -\- 2Nl—\t:cuq)+ QSOL‘ Cm” 4' W03 0*? so—et— QVOdouS S \MD-CQS 0’3 pochQ—cs EM fiYe’eove b. What is the experimental value for i if the observed osmotic pressure for a 0.10 M solution of Fe(NH4)2(SO4)2 at 25°C is 10.8 atm? O§WO‘\‘iC, Pressure, “ll : L./\,t. Q.T e L'Q’tw )MZOJOMO [L )Q: o.0‘81\ mog‘K “(r-no.8 o’rw “F: 15% 113: 2.038 K. L, .11— : til-w “O ' IU'Q‘T C040 moL-L"l(o.081\ l—-°\\'V‘"""'°""Hl*<-'Wigs“3 ’ (5 Pts) 17. Two forms of carbon are graphite, the soft, black, slippery material used in ‘lead’ pencils and as a lubricant for locks, and diamond, the brilliant, hard gemstone. Using the enthalpies of combustion for graphite (-394 kJ/mol) and diamond (—396 kJ/mol), calculate AH for the conversion of graphite to diamond: Cgrapme) —> Catamonas) The Lowbo§Hom YNAQ 0V6: Cyop‘n‘lcm +01% —e (01(3) m: ~3aq k3 Cd‘-°W°NC9‘ *01 ‘3‘ —-——> c0143» 13H: —%96 LC; ’70 obl—odw HA6, Yxm we wovfi: (,ywwxeCs) QR : —%C)L\ k3— C, Cudvopl/VI‘{CS\ % Cdiawcuo (9‘ QV‘ @ (6 pts) (6 pts) It {g EXAM I (Page 8 of 10) Name 18. During an exothermic process, 50 k] of thermal energy was transferred between the system and its surroundings. At the same time 100 U of work was done by the surroundings on the system. a. How many kJ did the internal energy of the system change? b. Did the internal energy of the system increase or decrease? c. Give the energy level diagram for the process. 9L 13L) mam :thfitLtwl b‘ éXOi’l/l€vwx{c m9 q :2 ~50 L4)” ©AT20065PR By HA6 Cow. d W: JMoo lr‘j [BU Csyclewfi : C’SO l/CJ'>+C+ loot/<3) 9.; U ' ()4 éAQ-J-FSOVJ’ Uc Lovfioiwim Cub‘fl‘W‘UA 19. What is the % (m/m) of a solutionYwhich has a molality of 2, a molarity of 1, and has a densityoflg/ml. need +0 ,gmd zggogoteA/looagoeowon d :. 5. 3/wL mofiovllyzi mofldziiy: 1 t 3 L (10“ L dim) MMMR A (1000 g) goam I m Wow 1 WA ’23 Co€uliom b€cowge Q o3 Coéuuon— ’1 (a Coat/4.4+: 4. a weak A lggoveul—e A A qoxt a 9&6? A, go a <o€Ul€A :2 a €o—CUHOM ’COXQ- QCOICuHmA' (00 a (canon [o OO i°3§oa€u+30w Name EXAM I (Page 9 of 10) (5 ptS) 20. Barium is the largest no radioactive alkaline earth metal. It has a 68% packing efficiency and a density 3.62 g/cm3 . What is the atomic radius of barium in cm? The volume of a sphere is V = 4/3(7tr3) and the molar mass of barium is 137.3 g/mol. Negev MOSS 3 \I/d <l?¥.3£388u><%36t1c2 ):31’9 Cw? wo u . a 0‘ \mo—Q (3)0 VO-QUwe O? (I wové Bu Q‘l‘ow9 9p002 iwcfluded lee % VofiuwQ 0’? (“We P3“ Glows) :26 CUE/l Woé Bu c1\-ow§ l—(Aewwgtres. 3 34.9 Cu? Eulowwspou’j be u» aim may i move Bu 0+0”; [00 Cu} [o+.+§9.'l ¥M£w§€&/€S N <16cw3 IW" A ._________..— W W“, ows 6.011X\0138u Q-\—QU\A§ VO’CUMe 0&— ..’L? K ‘ Cl BO o‘row il§e€£> : H‘gXlD CW 930 Glow \‘l’S—€€<€, :iL ’7’ V gTrv Name EXAMI (Page 10 of 10) Periodic Table 1 1 3 5 6 3 r I . 1.31.: 13 C (1 V " 9.012182 10.811 12010? 14001174 15.9994 8.9984133 1. 1 - 13 14 15 14s 17 1s ' ~‘ '_, Al Si 17’ S 1 Cl Ar 20.981538 230355 30.973781 32.0811 15.4527 39.0411 1 21 '1. 23 24 25 x 21 30 31 :12 13 34 35 30 ‘ SC ‘11 L21" M11 11:: Co ‘1 An (13 (11: As Se 131' 1w 44.955010 47.8151 511.9415 51.9%] 54933 .. 55.845 58.033200 5311934 13:1. 5530 60, 2:1 72.01 74.921611 11190 19.904 83.110 : . 1 ' .11 42 4.1 a 4 r 4 :18 49 s0 s1 H _ f 51 54 t ‘ " 11 Mo 1c L1 Ag Cd 111 Sn Sb '4 : 1 Xe 74 1 1 .1 92.900311 9504 1:911} 101.07 102905811 1 [77.8682 11M” 114.8111 113.111) 121.700 . 12330447 1312*) .1 71 1.1 74 75 .70 7 7; 70 so :1 11*1 r 1 as 1113 1 .11 1 1, 1‘ ' 121 W Re Us r I 1 1 «1 1339055 178.49 1809419 1113.84 188.20? .1 19 .21 l 1 I 1 . {U 34 Pt Au Hg " ’11 1: 1 Po , A: {11 7 [950711. “36.96635 2002‘} Infill”) 207.2 M39033 (21W) (210) 1222;: 107 "1‘9 "(I lll l2 “4 B lull S Eli" (239" 12552) ‘ "-3 (356) {359} (171] {277} 28f} 3 Some useful equations: 2-R = L 4-R = L2”2 4-R = Law Cgas = k Pgas d = m/V % (m/rn) ofA = (mass ofA / total mass of mixture) - 100 n = i M R T ATf = — i - kf- molality ATb = i 1 kb - molality Molality = nsolute / kg of solvent PA : XA in vapor ‘ PtOtal PA = XA in solution . PoA q=m~Csp'AT q=n~AH° XA=nA/(nA+nB) P7 AHW 1 1 . ln—L : — — —— T (K) = t (°C) + 273 fcc un1t cell = 4 atoms P. R T. T2 AU : q + w 11 (moles) = m (grams) / molar mass (g/mol) V (cube) = edge3 AH“ m = Z np AHfO (products) - 2 Hr AH f0 (reactants) Some useful data: R = 8.314 1 / (K - mol) = 0.0821 L - atm/(K - mol) 100 cm =1010 A 1 nm :109 m d (1120)I = 1.00 g / mL AHvap (H20) = 40.7 kJ/mol Csp (1120)l = 4.184 J / g °C Pwater (100°C) = 760 torr = l atrn = 760 mm Hg = 101,325 Pa 1 gallon (gal) = 3.785412 L NA = 6.022 x 1023 atoms / mol 1 g 2 6.022 x 1023 amu 1 1b = 453.6 g ...
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Toupa exam1 S06 key - Student ID Number K 6 ‘L Lab Sec. #...

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