Exam1.2009.Ans

Exam1.2009.Ans - Exam 1— Chem 481— September 23, 2009...

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Unformatted text preview: Exam 1— Chem 481— September 23, 2009 Prof. T. Baer Useful and essential information: R = 0.082 L—At/mK = 8.314 J/mK P = RT/(V-b) — a/V2 (Please print your name) The following two lines refer to the properties of water in its various phases: AfH°293{I-I20(s)] 2 ~291.8 kJ/ AfH°295[HZO(E)] = -285.8 kJ/m AfH°293{H20(V)] = -241.8 kJ/m P cptHzotsn = 38 J/m—K cptnzoan = 75 J/ni—K CP[H20(g)] m 33 J/m-K on(H20)=2.1x10'4K" AfHOICOfl = dw = 93de w = —nRTInV2/V1 AU = q + w AH = AU + APV ' a=V"(aV/aT)P KT = —V' I aft (a >0) [Tszflcvm = WV2 (aU/aT)v = cV (an/3T)P : CP [ea—“flax = [Wald]; ' 0 0 Show all your work. No credit given Without it. 1. 15 pts. Ethane has the following van der Waals coefficients: b = 01193 L; a = 5.507 atmL2 pressure of 1 mole of ethane gas confined at 300 K to 0.5 L assuming that a). . .it is an ideal gas, and b) a van der Waals gas c) Is . ” mar “- (snowman ‘3‘) ?' T" y ‘ 3L mol'z. 7' (Liv/t PV = RT[1 + (b — a/RTJV‘1 + (ti/W m ...] V293 = atm KT = 4.96xlO'5 at"I -393.5 kJ/m AfH°[CO] = -I 10.5 kJ/m AfHG [CH4] = 474.8 kJ/rn AfH°[C5H5] = 49.0 kJ/m E(av/lap}T Calculate the it the a or b c0efficient that dominates the non~ideality? .. 1Q? m 'g : 16%;)(300) __ gjo‘? b) ’1) ’ m V1 .- &0“?3) - 4: 5&th -« 2.25:): 283715237-«4; " M16: C) if) Com? ramped" cw Vefij (:3, SE at... m, ‘t‘i’iz L ' « w\.5’g MSWWW Ct ch‘F-glC1eI/Lf 6.; 15-96% yati a. b7 2,; tit/Wt. . - 2. 12 pts. What is the heat capacity (expressed in units of R) for the following ideal gases (explain your answers): CvtNe)=_3éi_1s cvtazotgihfi Cp(C0)= We g , ‘A S. m - - - “- 2- 21 r: ’- it! Nb u§,;}€IZ‘ 1/, Mimic? ,5 i2. z 2. g a CV -' 7" '3. I {g 1. Cv‘ "HZ: 3. 12 pts. Consider a real gas for which z = fl]— : 1+ [426]" — 201]P + 0036515”2 . Determine its Boyle RT temperature where the slope of 2 vs? goes to zero at low pressures. . t a: 7. .-- t ‘ _ w- i - grew; EST? 2 £4.29 i «Ital Tl(:003é$ T)? .. ‘ _... or _,_ ‘g gee am Attem— %_ / MI . xv‘ . M . ' mfiiwha 5’53“? Film- . V i‘WW: Aimgw 1%» gi'gj’fl‘é’ 30 em M 7s =v W- K 4. 10 pts. The internal energy of a liquid was determined to be U(T) = 20.2 + GUT + 0.0387"?2 I/mol, where T is in K. What is the molar heat capacity, CV, at 350 K? CV :- :' £5 4:- 3603??)7- Cvées‘o) .— g‘e 6+ 21%! = 3?- 37/45 ( a. ’P s 5. 10 pts The internai energy distribution of a liquid is given by P(E) = aEe'E’rRT. Determine the average internal energy of this liquid. (use information from pagi 1) 7 1”} ‘ E/‘Q Tré é a 530E Pat.) Cit: o tQ. («5 '"jz—fi‘e, <5 7 -- - a — L ’2‘ I " “W an EPCEJOW asedénewE/flg‘; 4‘9 = im— 6. 15 pts. An ideal gas is expanded isothermally at 300 K from I L to 10 L by three different paths. Calculate the work and heat (q) (in kl) done for each. ,_ ,_ j 3) against zero external pressure A U :G _ _ ' 4 7. 10 pts Calculate the Change in volume when 100 rnL of water is heated from 00 C to 100° C under a pressure of 1.01 atm (Le. it remains liquid up to 100” C). Use information on page 1. . .-I 1 I “if og_v(é_f)ia Z.‘ we l4 Se San/{d Veil .. q . '{m'bc :: 2.16mi. anal metal A _, )‘éozj go. IL V” I- it “"0“ “Await eat slam i=>49m§ Q“; X _ V V}? am 12:63 : @rzflaoz): (am a 1., 8. 6 pts What is the heat of melting for ice at 298 K? Use information from page 1' 43’ ,fi , g. '3- “ ARM : Agimw‘t) ” A-{Bl'rzqg (“13’ “2-9 I? H/ C i 7 QED 9. 8 pts Use the information in problem 8 to determine the heat of melting at 0 °C (273 K). Use heat capacity information from page 1. Draw a diagram of what you are doing. . 2.49 A Hst W} (12) fir . . If“) g 75’ .1 /.£ C? : 3? eff/EL Haggéx iii—s; #710612) - ' « ’ “rig—6‘25) b H = EEO—Se) “* (am - m 3&5 (if!) 6+ gauge .._. 4???? b I have neither given nor received aid on this exam Please sign ...
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Exam1.2009.Ans - Exam 1— Chem 481— September 23, 2009...

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