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Unformatted text preview: ‘ kley, Fall 2011, Chem.1314 Exam #3 Form B. Page 2 of 8.
. ‘ Aluminum reacts with excess hydrochloric acid to form aqueous alu ‘ 'num
chloride and MB 7 mL of hydrogen gas collected over water at 5&3} and A]; , kPa. If the vapor pressure of water at this temperature is 47. 6 torr how many
M. 1K < N
grams of aluminum reacted? ‘ “WWW, . L 6 2.85x10’: Al t We} ﬁat 717 a 4 H7. 7 Hm
B 2.6.4’x10'
We 2:84x10'2
D O‘i_8'8x10':
L775 E “41:47X10 A ~ 5 652; x 6 awﬂL
a 5526 ' 7&2) EFT: “RT Obgtg§ :36 37.7 1?
£171»
/”\ 41?? L ‘ ‘ l; L
,2 1 ~— 1. WW WW ,4. 222w
W I lmviwﬂw
2. Of the following pressure conversions which is incorrect: 1. 0.745 atm = 566 mm Hg 75.5sz ’ 1/
2. 0.155 kPa = 0.0451 in. Hg 1 mama x 1%“ ~
3. 36.5 psi = 252 kPa 'M Mm
4. 27 cm Hg = 0.355 atm 7‘ c1 ‘5! 1‘15 A “A W ..__, .3 v‘
5. 3.55 atm = 317 kPa 1557 PM ’9. kart), x (Wm 19%.? 2 ’1 x N \ MI? lal'w L 351W,“
1.77.7»Wif5 x m”... X A
B
C ,
D .
@ 31625.3» ! all WWW Z.LG 04”“ X “”73
“1.va \ 3. What is the rms velocity in m/s of uranium (235) hexafluoride at 273.15 °C? (A F“ 15? ‘1 "75141 W u ”.3
0 l‘ {$.11 kg? h,
.‘ 139 0,317qu :
B 19.5 ‘1 ‘ #3
C 198
D 262
E None of these is within 10% of the correct answer a: ? 3‘37“! at 247377" .
g/ t W
7% 3‘53qu [93 Rockley, Fall 2011, Chem.1314 Exam #3 Form B. Page 3 of 8. 4. How many liters of oxygen at STP are required to react fully with 16 grams
of phosphorus to form tetraphosphorus decaoxide at STP?
iVﬁﬁXET 79, V\ {1 2 F7 V“). T)
A 3.62 v: *5 R)
14.5
(g 57_9 'V‘ ﬂ ”9 +(0; “‘3' now
D 1792 “ ‘ P
E 80.0
jJc VHZT
; .r
v Mi;—
)‘LJ 3 5. How many photons are emitted by a 17 Watt LED light bulb used for a
desk illumination for 9.5 hours of studying chemistry, if the average wavelength
of the light is 488 nm (blue light which tends to keep you awake by lowering
the rate of production of melatonin, a chemical critical to the circadian rhythm in the human body) it gamma
\ n w 5 ® 1.96x10'17 7‘57?“ B 8.40x1022 6: W, C 5.1 (”m D 1.43 x 10 :j 7‘ E 8'84 X ‘0 2;; W t» 23H? m MN" m
~‘ liar": ~~ til i. W 6 Which of the following is not true? A An endothermic reaction absorbs heat as the reaction proceeds
@ the enthalpy change for an exothermic reaction is positive C the amount of heat released from an exothermic reaction is proportional to
the amount of reactants used up D it the coefficients of an equation are doubled, the amount of enthalpy
change per mole of reactions as written also doubles E If more moles of gas are formed than are used in a chemical reaction, the reaction will have a work value that is negative Rockley, Fall 2011, Chem.1314 Exam #3 Form B. Page 4 of 8. 7. What is the wavelength in meters of a photon required to ionize a single
electron atom, Li 2+, where the sole electron occupies the n=1 orbit of the Bohr
atom? W 2.12» rim '2’
‘ 1.012 x 10 '8 Q
B 1.012x10'8 1.. —
C 1.96 x10 17 V
D 1.76 x10 —;6
E 9'11X10 1.4013213?)
'7..th we”;
8. A 46 9. aluminum engine parts at an initial temperature of 85.9 °C releases 1463 J of heat. lf the specific heat capacity of aluminum is 0.900 J/gK,
what is the final temperature in °C of the part? @ 50.6 116351 9mm x (T? 357.01)
B 57.3 m
C 54.1 Wu "5’ “ 3‘3’V'QJ‘" 2063326
D 114.5
E 121.2 9. A 0.25 mole sample of sulfur hexafluoride gas at STP is taken to a final
pressure of 2.66 atm and 158 °C. What is the final volume in L of the gas? w‘yhﬁl‘d'gm
A 5.60 n/wulj 9” 3
B 1.33 e
c 1.218
D 1.40 ' “(if
a 3.32 W rt: 0: 0.7.an 312133235"; 1133131 Mmmmum—nw: wx » a 1. W t 'Z.(;C. Rockley, Fall 2011, Chem.1314 Exam #3 Form B. Page 5 of 8.
10. Which of the following combinations of n, l, ml are not allowed? 1. n=1, l= 0, ml=0
2. n=7, I: 1, ml=2
3. n=4, I: 2, ml=—2
4. n=2, I: 2, ml=1
5. n=3 I: 1, ml=—2 1, 2 and 3
2,4 and 5
2,3 and 5 A
B
C
C? 1,3 and 4
only 2 and 5 are not allowed 11. A first iron bolt at 135 °C with twice the mass of the second iron bolt made
of identical material is placed in thermal contact with the second iron bolt which is
at 45 °C. Both are placed in a calorimeter with negligible heat capacity. What is the final temperature in of the two bolts? A 105
B 75
© 90.0
D 100.0
E This problem cannot be worked unless the specific heat of iron is given 12. Which of the following (of selections A to E) is correct? 1. oxygen diffuses faster than C2H5 at the same temperature 2. sometimes real gases can have a PV/nRT ratio =1 at pressures other
than 0.0.atm. 3. intermolecular attractive forces cause the real pressure to be greater
than the ideal pressure
4. The ideal gas equation of state is correctly describes the state of real
gases only at STP ~5. Ajoule and a liter atm. are both units of energy (sometimes used also
as units of work) A 1,2 and 4 are true
B 2 and 5 are true
C only 2 and 3 are true
D all are true
(9 2,4 and 5 are true Rockley, Fall 2011, Chem.1314 Exam #3 Form B. Page 6 0f 8. 13. What is the wavelength in meters of a gamma ray emitted by Cobalt — 60,
rays used in medical treatment, if the photon has an energy of 1.33 MeV (million
electron volts, where 1 electron volt = 1.602 X 10 ‘19 J) 7‘ '3x if“
GD 9.32 x 10 '13
B 2.13 x 10 '13
C between 1.0 and 1000
D 1.24 x 10 ‘6
E There is insufficient information to answer this question (AL 4. 4,2,1; VI???” )1 1.41% 1.15% "'“‘ "'"M‘VW'WM‘mmmwmnwmnmmnWWW“ u .4 . 1.15 v, 15"”? 14. A 56.8 9. sample of dinitrogen tetroxide is confined in a 4.67 L vessel.
What is the pressure in atm. of this gas at 146 °C? W13“; (V: V1947 “m I“? r1172”?
A 1.35 v 2.
'3" B 5.97
5.3.1... c 2.43 1’ '~ mil
41. @D 3.87 v
E 0.109
{44.34 .3... . m.“ >‘ ”W“ 1 ”'1‘?
523 .  ,  Wm...
We“; L 15. Calculate the molar mass of a gas in g/mol at 435 mm Hg and 62 °C if 456
ng occupies 418 nL. am”; 41va
A 283.5
B 997
C 32 1 .  '
D 4.51 x 10 2 , ‘ ..
E 52.4 ,. Rockley, Fall 2011, Chem.1314 Exam #3 Form B. Page 7 of 8. 16. A 455 9 piece of copper tubing is heated to 92.5 °C and placed in an
insulated vessel containing 140 g of water at 24.5 °C. If the final temperature of
the entirety is 38 °C and the heat capacity of the calorimeter containing the water
is 8.5 J/K, what is the specific heat capacity of the copper in J/g—K? 3.14 \ Liaby 5.11. x (T510
3.25 1.615
0.972
0.324 moo©> 17. What is the frequency in Hz. of the photon emitted by the electron in a
Bohr model of the hydrogen atom in the transition from state n=6 to n = 3. ._ (I
' '2. " (”Rf ; “'1'?
\( l 3%: J 3:” [a2  imam?"
1f». »
(337:) MM?“ 18. A chemical reaction releases 417 J of energy and does 96.2 cal of work.
What is AE for this reaction in joules? 819 Ag 
321
+ 321
— 14.4 A
B
c
D
@ —498 « I 2. Witt21“"? . 2c.
27 /l_ l n a.
a 2323x182 3c“ ’71 ’2: "E”  inrhdé “01
= . X " w.. "k ,W «MW. .9 __
26 ‘ 1...: “1‘7
g ggiilgm ‘ *aﬂZ'B 8" it... xta
' q"? H ZH’MZ It , 1“
E 12 §.;§..31"i"ii:.. ‘1 .7 _ i“ 7,1334 yW
pawn” Rockley, Fall 2011, Chem.1314 Exam #3 Form B. Page 8 of 8.
19. Calculate AH° in kJ per gram of C02 produced by the following reaction: 2C2H6(g) +102(g) “>9C02(9) +loH20(9) A_H°f in kJImol : News?) f7(§43g) s
CzHe (g) 84.7 co2 (9) —393.5
H20 (g) 241.8
H20 (I) 285.8 A 2856 B —2586
C 46.2
D  64.8
0 @ Answer cannot be calculated because you need the enthalpy of formation
r oxygen gas or the answer is not within 10% of any of the listed answers 20. Calculate AHO in kJ for 2NOC(g) 9 Mb) + 02(9) + Cl2(Q) Given the following reactions: 1/2N2(g) + 1[202(9) > NO(g) AHO = 90.3 kJ ’1 NO(g) + 1/2 Cl2(g) —> NOCl(g) AHO =38.6 kJ 128.9 61.7
C ~61]
,D
E 219.2
403.4 ...
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