[Bush] Chemistry Exam #3 - Spring 2007

[Bush] Chemistry Exam #3 - Spring 2007 - NAME 1 Chemistry...

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Unformatted text preview: NAME 1 Chemistry 130 1 Sm 4 Spring 2007 Exam #3 PLEASE READ THESE INSTRUCTIONS CAREFULLY BEFORE BEGINNING THIS EXAMINATION. Select the best response to each question. There is only one best response to each question unless otherwise indicated in the question. There are 30 questions on this examination worth 3.33 points each. (Total of 100 points.) Check your test booklet to be sure that you have a complete exam with all 30 questions. Write your NAME and TEST NUMBER on your Scantron. Write your name on the first page of the test booklet also. Work each problem carefully on the test booklet or on the scratch paper provided. Then select the answer, which you feel is the best response. If none of the choices is close to your calculated answer, or if none is correct, then select the response "none of the above.” ALL ANSWERS MUST APPEAR ON THE SCANTRON. Your grade will be determined only by what appears on the Scantron, not by work on the test booklet. Look over your exam and work the easiest problems first, saving the more difficult ones for last. Be sure that you have correctly indicated your final choices on the Scantron before turning in your paper. If a question is incorrectly marked on the Scantron, it will be counted wrong even if it was correctly marked on the test booklet. If you have any questions about any of the problems on this exam, it is your responsibility to ask for a clarification from the instructor during the examination. Use the following information to answer questions #1, #2, and #3. Four identical 1.0 L flasks contain one gas each. The gases are H2, C12, CH4, and NH3. Each gas is present at 0°C and 1 atm pressure. Assume all gases behave ideally. 1. Which flask contains the largest number of molecules? a) the flask with H2 gas b) the flask with C12 gas c) the flask with CH4 gas d) the flask with NH3 gas Agosaévo‘s LOAD all flasks have the same number of molecules 2. In which flask do the molecules have the highest average velocity? @ the flask with H2 gas WW“ am. b) the flask with C12 gas (Ens a tmvz c) the flask Wlth CH4 gas d) the flask with NH3 gas mkmae—fl 3am (ED so W e) all four gases have the same average velocity QIALEWQN +CQ smaJLmtm has +€Q WW 3. In which flask does the gas has the highest density? flask with H2 gas flask with C12 gas dansufi=m om Wfl Sam \/ ~— flask with CH4 gas flask with NH gas 3 m we mengefimu Wm mug/5+ damle Use the ideal gas law to predict the relationship between n and T if gases have the same density ressure P and volume V are held constant. -— T a) n = kT where k is a constant PV' P _. Mng _,, UL b) n = kPZV where k is a constant Yb ' fi Us (RT M EM @ n = k/T where k is a constant d) n = k/R where k is a constant “3 l€‘/' e) n = k/P where k is a constant A gas occupies a volume of 180 cm3 at 750 torr and 25.0°C. What temperature is required to reduce the gas volume to 110 cm3 if the pressure is held constant? %V\ :9; LCM-0 a) 182 K )«CT‘ 52%, b) 488 K a 2’ Ti: \Ia. T. = "00“ (288.13 a 152K ‘ _ c) 15.2 K T "300”? +0 3 ngngo d) 40.9 K e) none of the above 11 , 13.0 +2135: ($8.63 The density of an unknown gas is 5.89 g/L at 20.0°C and 700 torr pressure. What is the molar mass of the gas?K, 200+A'73JS: 293-2 a) 2.02 x 10‘1 grams/mol W: “KT : g RT @ 1.54 x 102 grams/mol n; g c) 1.05 X 101 grams/mol . ‘ d) 1.69 x 101 grams/mol RI- ; :cngA-Ij‘] e) none of the above MW 3 ~3P-Tf' V J HUD: dRT : 5899<o.°61\/Kd?\\ (QC/hwy 4 02. P )‘ W = "5 “a 9. The kinetic—molecular theory of gases can account for all 3 of the following except: a) the pressure exerted by a gas on the walls of its container. b) the change in gas pressure with temperature. c) collisions between gas molecules. d) relative rates of the molecular effusion of gases. the condensation of a gas to form a liquid. W no \YVkQLfiWCXQJJCLOLLJEEUtC OM<$1M If 5.556 x 10'2 moles of hydrogen gas (H2) are p oduced by the reaction, 2A1 + 6HCl —> 2AlCl3 + 3H2 r, 325K and collected over water at 50°C, (vapor pressure of H20 at 50°C is 92 mm Hg), what is the volume of all gas present in the collection bottle at the end of the reaction? The barometric pressure is 760 mm Hg and the level of the water inside the collection bottle is the same as the level outside of the collection bottle at the end of the experiment. 13% =7Q=Dmmvk§ or \ 06mm A ' = 4r : 23 | a) 1-12 liters of gas inside the bottle T 83 2‘73 b < b) 1‘47 liters 0f gas inside the bottle PH—L: Vac—92; (Jog—‘DIV‘ @ 1.68 liters of gas inside the bottle wififcr M V W d) 0.982 liters of gas inside the bottle b») H; .03me he: e), none of the above 1 0% b‘fl H1“? H20 UCQN V: an=(5.ssb\/x5m0‘3(0;9§i~lh;am 323K :- .(o '15-— Weéfifikvflm 10$ 75291-01“ l 8L. What volume of oxygen gas will react with 20.0 L of sulfur dioxide if both gases are initially present at 1.0 atm and 100.°C? 2502(9) + 02(g) ‘9 2503(9) @ 10.0 L of 02 b) 40.0 L of 02 c) 30.0 L of 02 d) 5.00 L of 02 e) none of the above 10. The van der Waal‘s equation, 4 P+Qz?a)(V-nb)=nRT v attempts to describe the behavior of "real" gases. This equation correctly describes gas behavior over a wider range of temperature and pressure than the "Ideal" Gas Equation because the van der Waal's equation incorporates two corrections to the ideal gas law. What is the purpose of the constant b? a) to correct for chemical reactions between gas molecules. b) to correct for the random motion of gas molecules (:) to correct for the finite volume of gas molecules d) to correct for the average kinetic energy of gas molecules as a function of absolute temperature e) to correct for the intermolecular forces of attraction between gas molecules. 11. Chlorine gas is prepared by the reaction of potassium permanganate with hydrochloric acid according to the reaction, ZKMnO4 + 16HCl —+ 2KC1 + 2MnCl2 + 5C12 + 8H20 How many moles of KMnO4 are required to produce 2.500 liters of Cl2 gas at/fiTP? Assume 100% yield. \ law 0°C, W: (WI . 0.04460 mol KMno4 “mafia thxcx) 2800b b) 0.1115 mol KMno4 VJ (pme LWXQR'B K> Kmm c) 0.2230 mol KMnO4 d) 0.5575 mol KMno4 “Ch; O~H\S and e) none of the above o.\\\Smo\C—\L(2 mm KHan. : oLOWm( ma, UCi /V Cr RSCOLiai STP : 0. \Hsmol UL _, f / ll‘urm' L 5%“ mdp Cd's“) Macaw—9b (“0‘ -1‘<‘an7' 12. A sample of oxygen gas (32.0 g/mole) was found to effuse 5 at a rate that was equal to two times that of an unknown gas. The molecular weight of the unknown gas should be about Lo:\ mtmmmg 3% be >4 g/mol. 1 _ m 07, chx) HUJOO a) 64 T " m X HwLO% 32(39/“10‘ b) 16 \ooMSLcLoo C) 8 W 2_ 7.. @ 128 Vd—‘QOZ :4. 2: e) none of the above tax ODQ'O“? HWQ3:4C%Z-OC7 :. \28 Gym} «ac: 13. Consider the closed—end manometer shown below. What is the pressure inside the flask? The atmospheric pressure is 750 mm Hg. 25 mm a) 750 mm Hg b) 775 mm Hg 0) 725 mm Hg ‘l’25 mm Hg e) none of the above l4. Gases tend to behave most ideally under conditions of 6 a) high temperature and high pressure (j) high temperature and low pressure c) low temperature and high pressure d) low temperature and low pressure 8) all of the above 15. Which scientist is credited with the development of the barometer? a) Gay—Lussac b) Pascal c) Boyle d) Dalton Torricelli l6.A state function is a) a mathematical function that depends on the force times the distance. a mathematical function whose value depends only on the final and initial states of the system. c) a mathematical function whose value depends on the precise manner in which a given process is conducted. d) a mathematical function whose value is always zero for processes conducted at constant pressure. e) none of the above. 17. 18. 19. 2C(s) + 3H2(g) + 1/2 02(g) —9 C2H5OH(l) Enthalpy is 7 a) the heat associated with a process conducted at constant pressure. b) the heat associated with a process conducted at constant volume. c) the work associated with a process conducted at constant pressure. d) the work associated with expanding the system at constant pressure. e) none of the above. Internal Energy, AU, is a) the heat associated with a process conducted at constant pressure. the heat associated with a process conducted at constant volume. c) the work associated with a process conducted at constant pressure. d) the total energy associated with expanding the system at constant pressure. e) none of the above. Which thermochemical equation defines the standard molar enthalpy of formation of ethyl alcohol, C2H5OH(l)? k» .(\ My wag? \ I!wa a) 2C(s) + 6H(g) + 0(g) -> C2H5OH(l) b) 2C(s) + 6H(g) + 0(g) ‘9 €2H50H(l) C) C2H6(g) + 1/2 02(9) —> C2H50H(l) e) 2C(l) + 6H(g) + 1/2 02(g) —> C2H5OH(1) 20. Ferric oxide (Fe203) can be decomposed into iron metal and oxygen gas according to the following reaction, 1/2 Fe2O3 -9 Fe + 3/4 02 +412 kJ \rnotFk, AH = 56¢ What enthalpy would be required if 42.6 g of Fe metal are produced according to the reaction above? reaction. a) 481 kJ e) none of the above - 21. Assume 100% «befi— WF9 2 0.7(923md Fe 55 894—73 + 4\')_\/L3 —_‘ oth’B mo\ C12.) mot h2— - 5:4'13 Concrete hardens according to the following reaction, CaO(s)+ H2004 —9 Ca(OH)fls) Use the enthalpy of formation data given below to calculate AH° for the setting of concrete. a) AH° = b) AH° = C) AH° = e) none of the above Ewe—S g3: kJ/mol H20(g) -242 bJsz 2;? ‘ H20(1) —286 ~ Vimwfig C8.0(S) _635 Ca<0H)2<s> —987 _l980 kJ AH: —9871Q;J(‘m0\ mm ——638 kJ ‘ j —352 kJ —- \md HzDCQCZ‘ELlQ L. G\O\k&§k23 "15 —66 kJ w 2 _q8v7[4'j + 1% V34633hj -(ab I413 u.- 22. Work is force times distance b) force per unit volume c) mass times acceleration d) mass times velocity e) none of the above 23. Some beetles defend themselves by spraying hot quinone (C6H402) at their attackers. The beetles make quinone in a special chamber in their abdomen according to the following equation. C6H4(OH)2(1) + H202(l) —> C6H402(l) + 2HzO(l) Calculate AHO for this reaction given the following information. C6H4(OH)2(1) —> C6H402(l) + H2(g) AHO = +177.4 kJ H2(g) + 02(9) —> H202(l) \ AHO = ——187.8 kJ 2H2(g) + 02(9) —> 2H20<l> LUD— Q9“ AHO = —57l.6 kJ “1" AW0 a) +79.4 kJ “94/ 1— 87.8%] mam -’> H \ 5\ ‘ b) —296.2 kJ c) ——582 kJ @ —206.4 kJ CeH4fioH32(Q\4> C6H401(Q\+%\ “774%: e) none of the above MOM) + can, (0H3 in $2 CeH402 (23 + Z“;an bu : <4- 1878457|Jo + 07.4% ‘13 3 ~2051HQB 24. What is the difference between extensive and intensive 10 properties? (:> Extensive properties depend on the quantity of matter, while intensive properties do not. b) Extensive properties occur outside a system, while intensive properties occur inside. 0) Extensive properties are state functions, while intensive properties are not. d) Extensive properties include color and smell, while intensive properties include enthalpy and mass. e) Extensive properties depend on the kinetic energy of a system, while intensive properties depend on the potential energy. 25. How much heat, in kJ, is required to raise the temperature of 125 g Hg) from 24.3°C to64.9°C? The specific heat of water is 4.18 J/(g°C). RCA—‘- a) 33.9 kJ = 953(4483Xe49—2443 c3C. b) 42.4 kJ (‘3 CDC, 0 o @21.2 kJ \ 4 1°C d) 523 kJ : 9‘2‘3'5 3<Ei£9 = 321.2.‘4—3 e) none of the above 26. The heat capacity of a bomb calorimeter is found to be 5.68 kJ/°C. When a 1.652 g sample of glucose, CSHHOS, (l80.2 g/mol) is burned in the calorimeter, the temperature of the calorimeter increases from 24.56°C to 29.10°C. Calculate AU'per mole of glucose from the combustion reaction: CkHu06(S) + 6 02 09)'9 6 C02(g) + 6 B£)(g)' a - '3 (as - 29.1.0‘ > a) 15.6 kJ/mol of glucose 0(; o b) —42.6 kJ/mol of glucose : + Zsfi \QA+4‘S"'C' @ —2.81 x 103 kJ/mol of glucose ' waft d) —25.8 kJ/mol of glucose %¢°mbm\ 2 ‘ 1567qu 609’“ 0“ e) none of the above _25:7q\[3 : «.98th ‘53 \JoSQQ (“0‘3 ‘ MM 11 27. Which one of the following scientists made improvements that made the steam engine more efficient and started the industrial revolution? a) Pascal b) Joule c) Torricelli @ Watt e) Newton 28) A closed system differs from an isolated system in that a) the closed system exchanges matter with its surroundings and the isolated system does not. <E:>the closed system exchanges energy with its surroundings and the isolated system does not. c) the closed system exchanges both matter and energy with its surroundings and the isolated system does not. d) the closed system exchanges neither matter nor energy with the surroundings. e) the isolated system exchanges energy with its surroundings and the closed system does not. 29) When heat is absorbed by the system from the surroundings, the process is said to be , and the sign of q for process is a) exothermic; positive b exothermic; negative c endothermic; positive d) endothermic; negative e) spontaneous; positive 30) A person on a 2000 Calorie diet puts 2.0 tablespoons of 12 salad dressing on a salad. Assuming that the dressing contains 7.5 g fat per tablespoon, what percent of the daily Calorie intake has been consumed? (l g fat yields 9.0 Calories) a) 50% . b) 14% 91) Jrhscfigffks q‘owcx‘m : «31S Cab/mo @ 6.8% H05 3 {at .. d) 68% e) 3 4% _ ._l§éi, )< K3C>;: ENE3)%) 2000 ...
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This note was uploaded on 04/08/2008 for the course CHE 1301 taught by Professor Klausmeyer during the Spring '08 term at Baylor.

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[Bush] Chemistry Exam #3 - Spring 2007 - NAME 1 Chemistry...

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