key_exam1_F06 - 7 a.va SP“? K97 {Leash F 00 a m ,4, GRADE...

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Unformatted text preview: 7 a.va SP“? K97 {Leash F 00 a m ,4, GRADE / 100 = % 1)(30) a (3 pts)We developed an equation for the work done by a gas in an isothermal reversible process. It used the initial and final volumes ( V1 and V2). Assuming the gas is ideal change this equation to use the initial and final pressures (P; and P2). Then go on and use it in part b m/ Teens’r. l/IE=V2.1?L $4: %=% V2 *- —RTln —- r: w— in] ck -RTACQL) ,_ “fie-ma, Gm Fawn If you cannot do part a raise your hand. We’ll give you the equation, but deduct the points. K mfg 0 er . . a! g3"? b (27 pts) One mole of @trl-atonnc ideal gas a 100 IS compresse very slowly against a constantly changing pressure fi'orn 0.0 bar to 5.0 bar. The compression is done so that heat can ither enter or leave. Compute the following thermodynamic parameters and place your answers in the boxes given. Show your work in the box for any partial credit. Use CT‘CST' 30$; 1.5 at R = 8.31 .i/mole K and 1.00 L—atmos = 101 .1 Report your answers in Joules 5‘1"!" Nd PA 1LT m z. ) . ca 27‘ WIT mpg 5’6: F165. 5'? furl-0426. w: efl‘r’flh Fz/FJ eButlal'i; (Maigflh (:53 w(max o a? 35’ 27 (3v: 3&3“ 3'3"5 ’ AT: 0 =35“- “gs‘g 3‘3 57 We! K -r PM W than}! arm DO EITHER #2 or #3 Cross off the one you do not want graded. If no decision is made we will grade only #3 . 2) (20 pts) When we derived the equation for work we started with w = - IP(ext)dV Derive an expression for one mole reversible isothermal work using a modified vander Waal’s equation for gas behavior where the gas has volume but no attractive forces: P(V-b) = nRT where b is a constant 776;: = gar 7?“ Weir/(V11) (V2 “53 .- .. = .— m V .. .- R £7 - fFotV RTE—mfib> - 7" T (VF A) 515” 512* 539+ 01‘ 3(20 pts) If U= U(T,V) write out the total difi‘erential of U wit/fie" e123” e? U . At constant temperature = 0 for an ideal gas, but for-some real gases 6V T - 6V T a) (51313) 2 an -........— V3 AOL Again assuming constant T ; create an integrated equation for )5” as a fimction of V for the real .. .93 + '" b) (15pts) 0!“ *' GVJTCW W V2. 3 3 - -HL 3 ‘2 dagcin 4V MASK r.th dis! aaus oil/‘(zcm‘ V (VI “3 €29 6'9 012 on? FM DO EITHER #4 or #5 Cross off the one you do not want graded. If no decision is made we will grade only #5 . 4)(20 pts) a) (18)Water has an unusually high molar heat capacity at constant pressure. This is very important for cellular and ecological reasons in preventing rapid changes in temperature. Given the Cp of liquid water is 4.18 J/gK and that of ice is 1.94 .1ng at 0C. Suppose you were studying fieezing cells cryogenically at -80C in dry ice— acetone mix. Assuming the Cp’s don’t change much over this temperature range compute AH for the following reaction at -80C. 9H 02,; we: “r907?! HgOfl) —-> H20 (3) AH (0C) a -333 Jig 5 ' T ’ ’gf/ 4.- F Hie/wee) ash/(goo): :7 {TIES/+5?! 3:? _ ELF/5 / with x _F_. 5 ’1 ’1 C 5 $27 i [Sh/(6:15 zeHéfl "i SWT+ FEBHQB #435! magi/3:72P @4639) 3 ‘333; 1— 0.94 - ‘11, i8>(-goco> 5 ._ [54f f/ b) (2 pts) Comment on the sizeoof the new AH compared to the original 6‘ "333 "C459 : evil? game We? eta/v are” I g 22 M5 a m,- 6! as H eke-saw t“ M @755 5:98am“ Ea? wage-a “'0 $573325”de #5 (20pts) In a very short range of T and P the volume of a liquid may be expressed as V= K e-KPeuT Assuming a and K are constant in this range and V=V{P,T), Show that is a function of state Hr / -K ea):_+<l<e“’<°“ MK; 51” ‘ P T (=2 «K? "9(7— / / .fi‘fflq‘ v “RWKQ e u 5 i7 T 4L 5 i\ 93% _/ 1% VII/S. FW’VC77aeJ 6F 6) (30pts) In your own words glve a very bnef explanation of the followmg- dramngs may help: a) Cp> Cv foranidealgas byR. ,U N A775¢irds #39773”; 2’72 773“) 5“ U/éb/M T22“) & F {ff/66.5: “an”? CV {MUCDLUE'ZS ‘C/‘gif a: (U i flM/N‘ST ,t.iT‘P-x_;g;3 72?: <3? M, ea new"? r“ UM 4” ' ' ’P cave?" ~ in) CV for N2 at room temperature is much lower than the value of 7/2 R you would estimate 74K fiffifigtwg‘j A (at foo 5/ 73497" as 0/8 (.545, {9625731 j, a? @7724; W: Twas? agar" .237 T2— 293 mu? ame‘NoTsa'cV x‘gmw Oman: 0) Why is (the vander Waals “b” much larger than the actual volume of one mole of gas b : ggcmmu (/Oéowmi m5 £5,424 madam ca? 5537)») _: WAD/r2675 WOLECMCE 75 mm (—7“ 63% deeraffl (i a. E O ‘\ f“ d) U(1000K)> U(100K) . .. a . - /WA€3/‘/JG “T” )UCIZEflééj Qawbaw; buff/aw at“ “V/fc $240456“de $2.50 (édcgé‘aie hug; 765 ’NF/MM 4 5%?) on: 541:? size: @6236, 629: . e) W(rev) > w(irrev) C i 50 7336.41“ M, {away NJ) ' , _. q «'7 w ' to: ,ergmgtv w neg may: lgxf< {$07, 5c: 1 L356 C42va 12; Dame“ mete/v H” 77W " U i) Z([email protected]) >1 but Z([email protected]) <1 2 ; He“ ya ,5 Fae 24269925 ITS 75.. avg Al?" MM? awe“? gar/37% “4'3 aflaasmé gamma. . - _;/ M423 ’7‘3 Wch 5.406672 753 7E ‘3” D @TWMQTKM P Fewest “PWW m 52171237" ...
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This test prep was uploaded on 04/03/2008 for the course CHEM 480A taught by Professor Wesolowski during the Fall '07 term at University of Arizona- Tucson.

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key_exam1_F06 - 7 a.va SP“? K97 {Leash F 00 a m ,4, GRADE...

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