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Unformatted text preview: * ClIEM m3 3:913ng Quarter 2008 Dr. Di Pasquale) Exam 3" DO NOT ()I’ICN THIS EXAM UNTIL YOU ARE TOLD TO DO SO!!!
There are 10 questions worth 5 points each. You will have 50 minutes to complete the exam. Your
answers will be suhmitted and recorded using your lnterWritc PRS RF clicker. Your electronically
submitted answers are what will he sCorcd. so please make sure you input your answers properly and in
the units requested. Do not submit answers in scientific notation as they will not he correctly scored.
You may submit an answer for any question as many limes as you wish within the time period for the
exam. but only your last response for a given question will be retained. A Periodic Table with useful
constants and an equation sheet are attached. Feel free to write on this exam for your work. CLICKER INS'I‘RUCTIONS: 1. Join the RI“ class as you normally would by finding the class name or by typing the channel
number noted on the chalkboard. ’3. The top line of your clicker should display “'l'S'l‘:" which indicates you are in test mode (sec
helow).
ir te are Enter Test #
PR5
3. When asked to "Enter Test if". please enter your test form. This is form C. Press " and you will get a “Received” confirmation. If "Enter Test #" is not displayed or if you entered the
wrong test form. press the 4 button while "TST:" is displayed to change your test form.
4. Use the A and V buttons to navigate to the question numher you want to answer. You may
answer the questions in any order at your own pace. Answer with either a numerical answer or
A thru E for multiple choice questions. Press H and you will get a “Received” confirmation.
When you have submitted all of your answers and are finished with your exam. turn your clicker off inside of the lecture hall and do not turn it hack on until after the exam has concluded or your
submitted answers may be erased. 'JI TST: C l. The phase diagram for a pure substance is given below. The solid suhlimcs 3:30  I
 ’
m ! f
200 H / ._
Pressure, atm I qum'1 /
, Solid //
IJEI '— / '3 200 Temperatuze. I: .A‘J/Ell 400 K and ZUU Him.
[3} all 200 K and H10 mm.
C) all 300 K and 100 ulm. Elli \ ill 300 K and T5 alm. (13/), if warmed :1! any pressure below 50 allm. Version 3 Page I 2. The standard free energy of formation ul‘CSﬁl) is 65.3? kJmol ' at 298 K. This means
that at 298 K
A/C‘Szll) will not spontaneously l'orm C(s) + 23(5). ' C51“) is thermodynamicalIy unstable. :— f 2 7 i" j/mu’
9)” C83“) is thermodynamicalI); stable. _
.157 No catalyst can be found to decompose CSztl] into its elements. T2“ i:
E] CSgtlJ has a negative entropy.
. (,P“ _
t _ x I ,1 «arty5.] S ﬂ‘fjial’l’L 14"." J
a” ___ (tix I. _ LuffXylr‘nqats
“H,” . _ fix“, _ r) _' ' ’ In, {If
Gc 0 mm  1m ﬁ— 3 row!“ 9 37"” I
{d11'hllﬁ 3. Calculate AG in kJ'mol‘I for the t'ollmving process.
Hetg. l 211171.298 K} —> llelg. It} aim. 398 K} AG»; r’\ Quin Pl "7' (03"? rt town a? 27(3auﬁgyﬁamﬂi (1%") L; / l‘t __ cf I v If;
i 5'7 my (Wii
4. Calculate as“: in JK 1mol 1 at 298 K for the reaction
I‘lz(g) + thg) —> 2Hth) Allr" —546 kJrnol“. AS,“ : +14. JK"mol" , “AH l*7%
gg surf ———_  .  "  l/ ' Version 3 Page 3 5. Calculate the enthalpy of vaporization of CCh in kJmel" given that at 25°C. and 58°C
its vapor pressure is 107 and 405 Terr, respectively. Assume that the enthalpy of
vaporization is independent of the temperature. AHW : (Ti '4 Flt“W T; 2,205+: [91 7'40)", T2 ;_ 33 l L , l
(TU We?) a 7. 5:(‘9’1— mt; 3 I, ' '_.' :‘. FJW'zAJI Pressure, aim 5' me 200 300 40:: Temperature, K
What pressure must be applied to liquel’y a sample at 425 K? ) 350 atm
(é’ The sample cannot be liquefied at 425 K.
C} 150 atm
D) 50 aim
E.) 250 atm Version 3 Page 3 7. The phase diagram for carbon dioxide is given below. C05;r  Pressure, mm 9 H [a Temp31311116, K H Um lriph: point is ill 5. aim and —56°C. ill I aim and room lcnmcrzllurc
,A’)" solid L‘urhon dioxide is lhc stable phase.
,8”); liquid carbon dioxide is the stable phase.
,9.” gaseous carbon dioxide condcnscs.
(Eb gaseous carbon dioxidc is lhc slahlc phase.
ﬁrsolid L‘arhon dioxidc mulls. Vcrsion 3 Page 4 8. Which one ot'the following statements is true'.’
A) [.ahi'te is a term that refers to the thermodynamic tendency ol~ a suhstanee to
Lleeompose.
@' A thermodynamieully unstable emnpouncl is a compound with a positive stuntlartl
l‘ree energy of formation.
C) Spontaneous l‘eaetions always have ASP >0.
D} Spontaneous reactions always have AG.° ) (I). C t J A '
E) Spontaneous reactions always have All? < 0. / i "— 9. Use the Boltzmann formula to calculate the entropy in .lK'l at 'I‘ = {l K of [.00 mo]
iodobenxene. Chitel, where each molecule can be oriented in any of sis ways. f') 4 (a: M 7 T tut1N  .2 e H
3 kL  Fl p: ._ is elm/C) __ K k“;
C; \H/ :'\
a ‘K
C“?
“N.
w
>4
a...“
C r i) (It :5 H _><;/o' 1:: 10. The vapor pressure of water above 40 mL of water in a IOU mL container is 23.8 'I‘orr at
25°C. In Torr. calculate the vapor pressure of the water if the volume of the container is
ehanged to 50 mL'.’ Version 3 Page 5 ...
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 Spring '08
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