This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: CH 341, Physical Chemistry Test 1 Fall 2008} Constants: R = 8.314 or 0.08206 you know the units.
g = 9.80665 m 3'2 Name 1 atm= 1.0135x105 Pa
1bar=1x105 Pa Part 1: Answer 4 of the foliowing 5 questions. If you answer more than 4 cross out the one you
wish not to be graded. Otherwise only the ﬁrst 4 will be graded. 9 points each. k1 kg
1. F or the reaction mechanism A —> B —> C can you always use the steady—state
approximation, or if not, what must be true? I t2.<< EL 2. Thermal conductivity can be expressed as a iinear ﬂuxforce relationship: Jq=wt<$ where K is the thermal conductivity. A thermopane window is constructed ﬁ'orn two sheets of
glass with a narrow spacing. Calculate the thermal ﬂux in a thermopane window with a spacing of 2.00 mm between the panes of glass. Assume the Outside air temperature is 00°C and the
inside is 200°C. The thermal conductivity is 0.0252 J nt‘] K"E s‘E at 15°C and 1 atm. Assume a i elmfin t linear temperature gradient. 0. a ‘  an "r r»
_'J 3. Calculate the pressure inside your mouth that would be necessary to drink aysoft drink through a straw of length 20.0 cm. Assume the drink has the density of water at 200°C, 0.9982 g IIIL'I
and the atmospheric pressure is 1.000 bar. t. "i f
Pia '2 @0116? will
i also 6? P ~ Jr 0 ‘31ng ml
.ce “ " ,
W] 7501 PI or}; (1133:1170?) ‘7: !\J 4. A substance with a molar absorption coefﬁcient of 12,144. M“1 cm1 and a concentration of
2.33x10"S M is found in a lake. Calculate the fraction of the light incident at the surface of the lake that remains at :Cdeptlf? of 1.00 In. 0330 f E (a
' M25113C " M
\l 0 Je ’53 D ~I *M leenrmglaeewe he) JﬁJ‘) “3
_ _. 2 at?) C l1}— ;Hill M roam ' ‘13:: C 3 _ 0“ A 5’ 5.316; 5,3
'1 6,3546 : chgX/m’ _ ‘ CW l L) . 5. A photovoltaic panel can convert at best 12% of the light ﬂux into DC electrical power. The
conversion of the DC power from a solar panel to AC power that can be used to power appliances or to feed into the power grid is about'77% efﬁcient. The yearly average insolation for Boston is 4.16 kWh in'2 day'l. Calculate the AC power available per square meter from
photovoltaic cells operating at 12% efﬁciency in Boston. Express your results in joules per 1%” ’ second and also watts. [Hint l kWh = 3.6){106 J] vh‘biﬂﬂmﬁ
. : . ». 7 ‘ I v) A 2"? \2 ﬂ __J \ Il
Amt; with gamut 9—, :' WWW/(2 2—4. (%\ 7:5? it
i’lnLC'Gi'l ’7‘?" day. “L “3) "2 "VL ﬂ," hafs
:r r
4‘) R ’ . I ' jg
AC. 1%“ng ; #721231 (0.11.) ((3.77) , [6'5 51 1‘ mo F ha: “"35; hi" Part2: Answer 4 of the following 6 questions. If you answer more than 4 cross out the ones you
wish not to‘be graded. Otherwise only the ﬁrst 4 will be graded. 16 points each. ‘ l. {/94 3:23, lfjlf‘
6. The rate constant for the decomposipon of a certain substance is 2.80x10'3 L mol‘I s‘1 at
3dO°C and 1.3 8):]0'2 L niol‘l s'1 at 50.0°C. Calculate the activation energy and preexponential factor. ) ) \_
p, /(.er>><)0 ..a,_ jar; arm—— “J
H e“*——"". l f“ I? 5 303‘ C”
J» ( ’3 gas. (v girl K l a
r” A a, K
{.5469 1 ,QQ‘Héa/O k)
E“ 51““:le Q ; «Qt/ta
re “5463 T: a e 7. The following mechanism has been proposed for an enzyme reaction with two substrates, A
and B: M A EA 2 lat [5ij  la“; DEA] — lag. TEL/13 E15340. (i)
k:
4 «r ._ tn
EA+BE2>EAB+Y ’3 L31 LEAH/Bl" iz'slli’znﬂ ’6 D
k ,1 r ___t
EAB 3> E + P j; E»; 0—“) where EA and EAB are enzyme gorgeate complexes. Assuming that kg and k3 are large
compared to lg, show that the mechanism gives the rate law: d[P] _k1 1C2EHABI
dt _ k_1+i{g[B] A it'll M '
I ' I“? l L "‘ w K _. 4
5550.6 :1. “i‘Ci’x or. b ii gewi'i i2;
l 8. Find the integrated rate law for a third~order reaction with stoichiometry A —> B and rate law — d[A]/dt = k3 [A]3. (Give the linearized form, for example for a second order reaction the linear
form of the integrated rate law is 1/[A] — l/[A]O = kgt) ! A. w 2 3 7:5) t : (.1 l a A r‘ ‘1
t i i“ i W 71% "1 i i i ,1 e " 7/: ﬂ [/1] \j _g @Uiifg ~ l: 4—.
'x.
k_/ , 4" last +6 i ':
of 7172 of 217i M... 9. The cis—Irans isomeration of 1ethyl~2~methylcyclopropane is ﬁrst order in the forward and
reverse directions: _ kl) . W
C” “r “’0’” W ' k]
The reaction, starting with only as isomer has the time course given in the table, above. The
tongtime value for the CiS—isomer concentration is 000443 M. Determine (k1 + 1L1). in F‘ {ii} Ha it): 0‘ 01677 M
\‘Er‘t‘la’wivq 2‘ ‘ .a'
a \ \ ‘
rm Metal (ms) {000 3
” {El—“67? " (510m LE7 Kiliaiiz‘ﬂq) ;‘ EJE‘QK Sﬁ' 10. Consider a reaction with the stoichiometry: A + B > C + D. Assume that both A and B
absorb at a speciﬁc wavelength, while C and D do not. Assume also that A is the limiting
reagent, [A]D < [BL]. Remember that the concentration of A is determined by the extent of the reaction: [A] t [AL—é. Assume that the absorbance of the mixture is the sum of the absorbances:
A = EAI’ [A] + SE? [B], where 8A and 813 are the molar extinction coefﬁcients of A and B,
respectively. Show that: El _ [MOLE _ A—Am
[ALF . — ADMAc) ~ . . ..\ f5: 9 51.20%. Eggs] ’1 gig C mil?) J” may i~~ alter {rem gear; [ID—so 4 1 2
11. Solve the matrix equation (I 0. = [I] for x and y.
—1 [HI t_(1\31]l M12) _ M22 —M12] ]
m. M21M22 _ IMI —M21 M11 w) was; I» ml. 1* «~I , r ,. Of” "1 ‘ #2 H (oaﬁﬁlﬁ (4)0) 23 /_ ./C> m or ...
View
Full
Document
This note was uploaded on 10/06/2010 for the course ES ES271 taught by Professor Machaut during the Spring '10 term at Colby.
 Spring '10
 Machaut

Click to edit the document details