s2005 2 - Midterm #2. ChBE 2100, Summer 2005, p. 1/8 is...

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Unformatted text preview: Midterm #2. ChBE 2100, Summer 2005, p. 1/8 is r»; .k 7. our. ChBE 2100 5’ Ch ' IP p- -| .v- -..~ :- .4 em'°§un1312‘is§ooé'"°'pes RESERVE Dink Midterm #2 June 22, 2005 Printed name: (Please write your name on the back of the last page of the exam too) Note that there are 4 problems each worth 25 points. Note also that there are some tables at the end of the exam that you may find useful. Please read the questions carefully. This examination is closed book. However, you are allowed one 8.5" x 11" piece of paper (one side only) with any information you want on it. These notes must be your own and may not be copied from another person. You are also allowed to bring a calculator, although programmable calculators and wireless devices are prohibited. To receive full credit on each problem. you must present your solution clearly. For each problem, identify the (appropriate) balance equation(s) needed to solve the problem; label all variables, equations and diagrams; and include a brief word description to explain each step in your solution. Numerical answers without units or explanations will not receive credit. I pledge that l have abided by the above rules and the Georgia Tech Honor Code. I have neither given nor received inappropriate aid on this exam. Signed: “h Problem 1 __/25 Problem 2 __/25 Problem 3 ___/25 Problem 4 /25 Total /1 00 Midterm #2. ChBE 2100, Summer 2005. p. 2/8 Problem 1 (25 points total) a. (6 points) A vessel contains nitrogen and benzene in the vapor phase. There is no liquid phase present. In order to create a liquid phase, which of the following should you do? Check all correct answers [3 raise the temperature [I add more benzene vapor El raise the pressure [I add methane gas (does not condense) E] add more nitrogen gas El add liquid nitrobenzene (does not vaporize) b. (5 points) The vapor pressure of mercury at 150 °C is 0.41 kPa. The vapor pressure of mercury at 450 °C is 448 kPa. What is the vapor pressure of mercury at 300 °C? kPa c. (2 points) If methanol vapor is in equilibrium with liquid methanol, must the vapor be saturated? El Yes [I] No d. (2 points) The vapor pressure of ammonia is 1 atm at —33.3 °C. Liquid ammonia is kept in a sealed flask at —33.3 °C; the gas above the liquid contains air and ammonia vapor at a pressure of 2.5 atm. What is the partial pressure of ammonia in the gas? atm e. (3 points) Blood serum is composed mostly of water, salts, and proteins, but does not contain the cells found in full blood. Sometime serum is stored frozen for later analysis of blood chemistry. ls the freezing point of blood serum (select one) D less than C] equal to El greater than the freezing point of water? f. (2 points) What is the vapor pressure of propane at 50 °F? psi g. (2 points) There is a vapor-liquid equilibrium in which 002 forms 90 mole% of the vapor phase and is dissolved in the liquid at a concentration of 0.01 mole% at a known temperature. To calculate the pressure of this system, which would you use? (select one) D Raoult’s Law El Henry’s Law h. (3 points) List three special design features of the Alaska pipeline 1. 2. 3. Midterm #2, ChBE 2100, Summer 2005, p. 3/8 Problem 2 (25 points total) A humidifier is fed with air at 1 atm, 20 °C, and 30% relative humidity at a rate of 10 m3/min and with water at 20 °C. The humidifier is heated and operates at a temperature of 80 °C at 1 atm. A vapor-liquid equilibrium exists within the humidifier. The humidifier discharges a vapor stream. The humidified also discharges a liquid stream at 2.5 gal/min. What is the flow rate of the inlet water stream? gal/min Midterm #2, ChBE 2100, Summer 2005, p. 4/8 Problem 3 (25 points total) Nitrogen is bubbled through a liquid mixture that is maintained with equimoiar amounts of benzene and toluene. The system pressure is 3 atm and the temperature is 80 °C. The nitrogen flow rate is 1 moi/min. The gas leaving the bubbler is saturated with benzene and toluene vapors. Estimate the rate at which benzene leaves the bubbler moi/min ; °l\‘6‘0 J Midterm #2, ChBE 2100, Summer 2005. p. 5/8 Problem 4 (25 points total) Consider the graph below containing vapor-liquid equilibrium data for mixtures of ammonia (NH3) and water at a “mystery” pressure. (a) (3 points) If 1 mol ammonia and 2 mol water are mixed and brought to a temperature of 300 K (at the “mystery” pressure), which phase(s) are present? (circle one) liquid only liquid and vapor vapor only (b) (3 points) Starting with 1 mol of pure water, what is the minimum amount of ammonia needed to be added to form a vapor-liquid equilibrium at a temperature of 325 K (at the “mystery” pressure)? mol (c) (3 points) What mole percent of ammonia would be present in this vapor phase? % NH3 (d) (3 points) At the “mystery” pressure, what is the boiling point of water? K (e) (11 points) Use Raoult's Law to determine the "mystery" pressure. atm (f) (2 points) The actual "mystery" pressure is 4 bar. in a sentence, comment on why Raoult’s Law makes such a poor prediction. 1"?) w' 9'9, ‘mh “at, 1600 "1 Midterm #2, ChBE 2100, Summer 2005. p. 6/8 Vapor pressure. p' (Ry/in?) Temperature (°F) 50 75 100 150 200 Figure 6.1-4 Cox chart vapor pressure plots. (From A. S. Foust et al., Principles of Unit Operations, Wiley, New York, 1960. p. 550.) Table 8.4 Antoine Equation Constants" B T + C Example: The vapor pressure of acetaldehyde at 25°C is determined as follows: 1600.017 25 + 291.809 : PE2H40(25°C) = 102'9551 = 902 mm Hg M log10 p’ = A — T in °C p‘ in mm Hg, log10 pgzm(25°C) = 8.00552 — = 2.9551 Compound Formula Range (°C) A B C M Acetaldehyde C2H4O —0.2 to 34.4 8.00552 1600.017 291.809 Acetic acid C2H402 29.8 to 126.5 7.38782 1533.313 222.309 Acetic acid* C2H4OZ 0 to 36 7.18807 1416.7 225 Acetic anhydride C4H603 62.8 to 139.4 7.14948 1444.718 199.817 Acetone C3H6O —12.9 to 55.3 7.11714 1210.595 229.664 Acrylic acid C3 H402 20.0 to 70.0 5.65204 648.629 154.683 Ammonia* NH3 -83 to 60 7.55466 1002.711 247.885 Aniline C6H7N 102.6 to 185.2 7.32010 1731.515 206.049 Benzene C6H6 14.5 to 80.9 6.89272 1203.531 219.888 n-Butane n—C4H10 —78.0 to —0.3 6.82485 943.453 239.711 i-Butane i—C4H10 —85.1 to -11.6 6.78866 899.617 241.942 Pyridine C5H5N 67.3 to 152.9 7.04115 1373.799 214.979 Styrene CgHg 29.9 to 144.8 7.06623 1507.434 214.985 Toluene C7H3 35.3 to 111.5 6.95805 1346.773 219.693 1,1.1—Trichloroethane C2H3C13 -5.4 to 16.9 8.64344 2136.621 302.769 1.1,2-Trichloroethane C2H3C13 50.0 to 113.7 6.95185 1314.410 209.197 Trichloroethylene C2HCl3 17.8 to 86.5 6.51827 1018.603 192.731 Vinyl acetate C4H602 21.8 to 72.0 7.21010 1296.130 226.655 Water* H20 0 to 60 8.10765 1750.286 235.000 Water* H20 60 to 150 7.96681 1668.210 228.000 m—Xylene m—Cngo 59.2 to 140.0 7.00646 1460.183 214.827 o-Xylene 0-C3H10 63.5 to 145.4 7.00154 1476.393 213.872 p-Xylene p-Cngo 58.3 to 139.3 6.98820 1451.792 215111 R THE GAS CONSTANT 8.314 m3-Pa/(mol~K) 0.08314 L-bar/(mol-K) 0.08206 L-atm/(mol-K) 62.36 L-mm Hg/(mol~K) 0.7302 ft3‘atm/(lb—m0le~°R) 10.73 ft3~psia/(lb-mole-°R) 8.314 J/(mol-K) 1.987 cal/(mol-K) 1.987 Btu/(lb—mole'°R) Illllllllllll Midterm #2, ChBE 2100, Summer 2005. p. 7/8 mnva mdvvm mg: 0.83 mi: v.3 8080.0 58.0 mm Wmva m4»va odofi mwovm 0.02 va 838d wmmod vm WHva edva Ndo wwovw Nam 03 waged $8.0 mm Nwmmm m.vmvm Qmw odovm ogmm wsm Noofiood vmmod om mdmmm odwvm 0mm mdovm Wmh fimo 8386 808.0 m: odmmw wdcvm H50 93mm HBO Tmn .5386 Sde 3 NBNWN nwovm w.wm wéomm w.ww on 338.0 320d 3 odmwm Wmnvm Vow fimomm Vow wdo 08806 530.0 NH 0.3mm ofinvm 04$ @0me QNV v.03 ooofiood RN56 3 NSWN ofimvm 9mm cdwmm 9mm 042 000506 N586 m 0.33 vfiwvm Nam w.mwmm NWN wfimw @0386 $300.0 0 Qwomm fimovm wéfi fifiwmm $3 mfimfi 00386 mfiwood v NmOmN wdmvm Tm mwnmm v.w 0.0: 0830.0 3595 N o. Ema 0.8mm 06+ odnmw OBN Noam 8300.0 208.0 3.0 If EmBm nonmuoagm $35 588m $35 535 $55 Guava A06: 305% 36:35 388583 Illllllllllll!‘ 603m? uhaumhumfifih "Emuum 3335mm mo mucuomorm m4” 935—. = 107 dyne-cm kW-h = 0.23901 cal ) 88 :8 3? 88 ES 82 828.9 8m? 82 .M 88 $88 was 88 ca: 83 358% 8:: 83 z m m 88 888 E: 38 85 82 83386 8.3.0 8 o m m $8 $88 888 S8 28 23 328.0 $50 8 m w r A. 88 888 8.88 88 28 838 8286 88d 3.. N m m my L w a C m $8 :88 E8 88 38 888 $285 8m; 8 5. m0 m n n m m, 04 x 88 888 ES 88 $2 88 8286 28.0 8 __ 1 m M. m 3% m % 88 88 £8 88 $8 82 828d moved 8 __ 6 2 2 0 w 02C 9. $8 88 38 $8 38 EN 828d :86 8 m. __ 3: __ x H m __ 88 888 :8 $8 38 E8 828.: $8 8 0 m 25 m m m 8: 88 88 38 3:8 8.9m H88 8285 85. mm __ H mm. m m. w 88 88 38 $8 38 me; 8386 82.0 ow d 3 . 4 . H at y 3 g __ m t .m % w W N :91 u 288 34.88 2: 3:8 2: >8 3888.3 88.0 8 m __ = & \l/ HdeN Ndfivm Qwfi: NAva QWOH OAV moomood ommcd am w M. = __ 4 \I/ m = “m ( 7 3 = 105 dynes 28,317 cm 1 kg-m/s2 = 3.2808 ft 116f = 32.17416m-ft/s2 1.01325 x 105 N/m2 (Pa) = 101.325 kPa = 1.01325 bar 1.01325 x 106 dynes/cm2 760 mm Hg at 0°C (torr 14.696 Ibf/in.2 29.921 in. Hg at 0°C 12m. = 1/3 yd = 0.3048m = 30.48 cm 11 =1N-m : 107 ergs 1m3 =1000L =10‘3cm3 =1O6mL 35.3145 113 = 220.83 imperial gallons 1056.68 qt 100 cm = 1000 mm = 106 microns (11m) 1728 16.3 39.37 in. 0737616115f = 9.486 x 10*4 Btu 1.341 x 10‘3 hp 1 W = 1J/s = 0.23901 cal/s 2.778 x 10‘7 103 = g k 3 9 5 3 5 4 0 = g 3 9 5 3 5 4 = n o t A.» 0 1 X 5 = Z 0 6 1 = m m 1 m m 2 6 4 0 2 2 z n m C .m e m m 0. __ g m 1 __ g k 1 Equivalent Values 1 atm 1m Quantity Pressure FACTORS FOR UNIT CONVERSIONS Midterm #2, ChBE 2100, Summer 2005, p. 8/8 ATOMIC WEIGHTS AND NUMBERS M Atomic weights apply to naturally occurring isotopic compositions and are based on an atomic mass of 12C = 12 Atomic Atomic Atomic Atomic Element Symbol Number Weight Element Symbol Number Weight Actinium Ac 89 — Iridium Ir 77 192.2 Aluminum Al 13 26.9815 Iron Fe 26 55.847 Americium Am 95 — Krypton Kr 36 83.80 Antimony Sb 51 121.75 Lanthanum La 57 138.91 Argon Ar 18 39.948 Lawrencium Lr 103 — Arsenic As 33 74.9216 Lead Pb 82 207.19 Astatine At 85 — Lithium Li 3 6.939 Barium Ba 56 137.34 Lutetium Lu 71 174.97 Berkelium Bk 97 — Magnesium Mg 12 24.312 Beryllium Be 4 9.0122 Manganese Mn 25 54.9380 Bismuth Bi 83 208.980 Mendelevium Md 101 — Boron 'B 5 10.811 Mercury Hg 80 200.59 Bromine Br 35 79.904 Molybdenum M0 42 95.94 Cadmium Cd 48 112.40 Neodymium Nd 60 144.24 Calcium Ca 20 40.08 Neon Ne 10 20.183 Californium Cf 98 — Neptunium Np 93 — Carbon C 6 12.01115 Nickel Ni 28 58.71 Cerium Ce 58 140.12 Niobium Nb 41 92.906 Cesium Cs 55 132.905 Nitrogen N 7 14.0067 Chlorine Cl 17 35.453 Nobelium 7 No 102 * Chromium Cr 24 51.996 Osmium Os 75 190.2 Cobalt Co 27 58.9332 Oxygen O 8 15.9994 Copper Cu 29 63.546 Palladium Pd 46 106.4 Curium Cm 96 — Phosphorus P 15 30.9738 Dysprosium Dy 66 162.50 Platinum Pt 78 195.09 Einsteinium Es 99 — Plutonium Pu 94 — Erbium Er 68 167.26 Polonium P0 84 — Europium Eu 63 151.96 Potassium K 19 39.102 Fermium Fm 100 — Praseodymium Pr 59 140.907 Fluorine F 9 18.9984 Promethium . Pm 61 — Francium Fr 87 — Protactinium Pa 91 — Gadolinium Gd 64 157.25 Radium Ra 88 — Gallium Ga 31 69.72 Radon Rn 86 — Germanium Ge 32 72.59 Rhenium Re 75 186.2 Gold Au 79 196.967 Rhodium Rh 45 102.905 Hafnium Hf 72 178.49 Rubidium Rb 37 84.57 Helium He 2 4.0026 Ruthenium Ru 44 101.07 Holmium Ho 67 164.930 Samarium Sm 62 150.35 Hydrogen H 1 1.00797 Scandium Sc 21 44.956 Indium In 49 114.82 Selenium Se 34 78.96 Iodine I 53 126.9044 Silicon Si 14 28.086 Silver Ag 47 107.868 Tin Sn 50 1 18.69 Sodium Na 11 22.9898 Titanium Ti 22 47.90 Strontium Sr 38 87.62 Thugsten W 74 183.85 Sulfur S 16 32.064 Uranium U 92 238.03 Tantalum Ta 73 180.948 Vanadium V 23 50.942 Technetium Tc 43 —— Xenon Xe 54 131.30 Tellurium Te 52 127.60 Ytterbium Yb 70 173.04 Terbium Th 65 158.924 Yttrium Y 39 88.905 Thallium T1 81 204.37 Zinc Zn 30 65.37 Thorium Th 90 232.038 Zirconium Zr 40 91.22 Thulium Tm 69 168.934 ————_——_—_____________—__ ...
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This note was uploaded on 02/22/2012 for the course CHBE 2100 taught by Professor Staff during the Summer '08 term at Georgia Institute of Technology.

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s2005 2 - Midterm #2. ChBE 2100, Summer 2005, p. 1/8 is...

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