Exam3_PracticeE_Solutions

Exam3_PracticeE_Solutions - 001 [part 1 of 1} 10 points The...

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Unformatted text preview: 001 [part 1 of 1} 10 points The pressure at 20,000 feet above sea level is about 400 mniI-Ig. To what does this corre— spond? 1. 53.3 kPa correct 2. 525 Pa 3. 0.525 kPa 4. 0.525 Torr 5. 53.3 g - m‘l - s—2 002 [part 1 of 1] 10 points A 5.5 L sample of nitrogen at sscc and 0.75 atin is allowed to expand to 13.0 L. The tem— perature remains constant. 'What is the final pressure? 1. 0.053 atm 2. 3.0 atm 3. 0.12 atm 4. 0.75 atm 5. 0.33 atm correct 003 [part 1 of 1} 10 points A certain quantity of a gas occupies 51.3 ml. at seco. H the pressure remains constant, what would be the volume of the gas at 1230C? 1. 32 ml 2. 52 ml 3. 22 ml 4. T2 ml correct 004 [part 1 of 1} 10 points A. sample of 37: gas occupies a volume of 745 nil. at STP. 1What volume would Kg gas occupy at 155 CC at a pressure of 353 torr? 1. 2415 ml. correct 2. 3225 ml. 3. 312 ml 4. 533 ml 5. 555 ml 3. 1722 ml. '3. 323 ml 3. 233 ml 005 [part 1 of 1] 10 points The normal respiratory rate for a human be— ing is 15.0 breaths per minute. The average volume of air for each breath is 505 cm3 at 203C?- and 2.05 X 10'4 Pa. 'What is the volume of air at STP that an individual breathes in one day? Give your answers in cubic meters. 1. 100n13fday 2. 505 cmgfday 3. None of these 4. 505 mafday 5. 2.05 cmglr'day 0. 2.03 malx’day correct 003 [part 1 of 1} 10 points 1What is the density of hydrogen gas at STP? 1. as gfL 2. 0.032 gfL correct a. 11.2 gfL .1. sea gfL 007 [part 1 of 1} 10 points At ST‘P, 22.4 liters of oxygen ga5[02]| will have a mass of 1. 28.0 g. 2. 32.0 g. correct 3. 22.4 g. .1. 15.5 g. Consider two balloons filled with gas and ar— ranged so that P. V. T are the same in both. The number of molecules in each balloon 1. could be different if the filling gases are different. 2. would be the same only if the filling gases are the same. 3. must be different. 4. must be the same. correct 009 [part 1 of 1] 10 points 'What is the density of xenon gas at 750 kPa and 259C? 1. 15.5 g -L-1 2. 5.252 g - L—1 5. 75.5 g -L—1 4. 5.25 g -L—1 5. 32.7 g -L_1 correct 010 [part 1 of 1] 10 points How many atoms of argon occupy 1 ml. if the temperature is 3003C and the pressure is 1.55 x 15—3 Torr? 1. 1.55 x 1513 correct 2. 2.55 x 15—11 5. 2.45 x 1519 5. 1.25 x 1515 5. 5.22 x 1513 011 [part 1 of 1] 10 points 'What is the number of molecules in 22.4 L of nitrogen at exactly 03C and 3 atm? 1. 1.51 x 1533 2. 1.51 x 1534 correct 5. 2.51 X 1523 4. 5.52 x 1534 5. 15.5 x 15-23 012 [part 1 of 1} 10 points Jane works for the Dr. Pepper Company. She is told that she must add 4.510 liters of CCg to each vat of Dr. Pepper at STP. How many grams of C02 does this represent? 1. 8.84 g correct 2. 4.440 g 3. 0.00456 g 4. 2.22 g 5. 5.251 g 013 [part 1 of 1] 10 points Consider the reaction 4 KCfls] + 2C02[g} —.t 2K2co3[s} + 20255}. How much KC: is needed to react with 75.0 L of carbon dioxide at STE”? 1. 13.4 mol 2. 0T0 mol correct 3. 1.0? mol 4. 0.838 mol 5. 3.35 mol 014 {part 1 of 1] 0 points Lithium metal reacts with nitrogen gas to produce lithium nitride. 1What volmne of nitrogen gas at 2 3.1.7111 and 175°C is required to produce 75.0 g of lithium nitride? 1. 39.5 L correct 2. 119 L 3. 30.151I L- 4. 15.5 L- 5. 79.2 L- 015 {part 1 of 1] 10 points A. sample of dangerously reactive fluorine gas is contained in a stainless steel container which has a 35 L capacity at a pressure of 150 pounds per square inch and a temper— ature of 230°C. 1What mass of fluorine gas sample is in the stainless steel container? 1. 20.5935 g 2. 31.0402 g e. mecca g 4.11.5531 g 5. 539.753 g correct 015 {part 1 of 1} 10 points A flask contains 0.123 moles of an ideal gas that occupies 731 mL. A. second flash at the same temperature contains 0.0712 moles of the same gas. The pressure is the same in both flasks. 1‘What is the volume of the second flask? 1. 39.130 mL 2. 1350 mL 3. 5.3 mL 4. 452 mL correct 5. 904 mL 017 {part 1 of 1} 10 points A 75 mL metal bulb is filled with 42.1 g of CH4 and 3.23 g of NH3. 1What is the total pressure in the bulb at 31500? 1.1.312»: 103 torr 2. There is no observable pressure in the bulb because the metal bulb does not allow the exterior atmosphere to exert a force. 3. 1.33 X 10? torr correct 4. 2.30 torr s. 7.33 x 105 torr 018 {part 1 of 1] 10 points Determine the molecular weight of a com— pound given the gas phase data: mass of 27.54 g._ temperature of 134°C. pressure of 055 torr, volume of 14.32 L. 1. 0.045 gf'mol 2. 35.7 gf'mol correct 3. 279 gfmol 4. 191 gfmol 5. 24.0 gf'mol 1‘Which of the following is NOT true about gases? 1. The gas is at STP if it is at 273 K and 1 atm. 2. The density of a gas can be increased by applying increased pressure. 3. Gases can expand without limit. 4. Gases exert pressure on their surround— ings. 5. The volume a gas occupies is directly proportional to its molecular weight. correct U23 {part 1 of 1} ID points A. 113 g sample of impure magnesimn oxide is decomposed to produce 22 L of oxygen gas at STP. Assuming that the only substance to decompose in the sample is magnesium oxide, what is the percent of the magnesium oxide in the original sample? 1. D.Dl?5% 2. EDIE-4% 3. 39.235723 4. 71.423592 correct 5.735714% [121 {part 1 of 1] 13 points A. mixture of oxygen and helium is 32.3% by mass oxygen. It is collected at atmospheric pressure {745 torr}. 1What is the partial pressure of oxygen in this mixture? 1. 333 Torr 2. 412 Torr 3. 583 Torr 4. 445 Torr correct 5. 299 Torr 022 {part 1 of 1] 1!] points You have learned from kinetic molecular the— ory that for an ideal gas there is an inverse square root relationship between gas velocity and mass. Given this information, what is the ratio of gas velocities for H; to (302? 1. 1 to 22 2. 1 to 4.39042 3. 22 to 1 4. 2 to 44 5. 4.59342 to 1 correct U23 {part 1 of 1} ll] points 1Which one of the following statements is NOT consistent with the kinetic—molecular theory? 1. Collisions between the molecules of a gas are elastic. 2. Except near the liquification point, the attractive forces between molecules of a gas are very small. 3. A. given sample of a gas is mostly empty space except near the liquification point. 4. The attractive forces between the molecules of a gas become significant only at very low temperatures. 5. The volume occupied by the molecules {only} of a gas becomes significant only at a very low pressure. correct 024 {part 1 of 1} 10 points If the average speed of a water molecule at 25°C is 540 m - s_1._ what is the average speed at IDDDC? 1. SDI mfs 2. 320 mfs 3. 572 mf's 4. T15 mfs correct 5. 5123 mf's Balloon K is filled with the carbon monox— ide. Balloon Y is filled to the same volume with carbon dioxide. The balloons are left for several days in a room at constant tempera— ture. 1Which balloon would you expect to be smallest after this period of time? 1. Both would be the same size. 2. Balloon X correct 3. Balloon Y D23 [part 1 of 1] 10 points At DOC- and 1 atmosphere of pressure. which of the following gases would have the highest average molecular speed? 1. NH3 2. Ar 3. C02 4. H2 correct 5. N2 D2? [part 1 of 1] 10 points Calculate the ratio of the rate of effusion of C303 to that of He. 1. [1.099 : 1 2. [1.30 : 1 correct 3.11:1 4.12:1 5.33:1 D28 [part 1 of 1] 10 points List the gases H2, C3H3F, NZ, C3F4, HF in or— der of DE-CEHE-ASIFG tendency to behave as ideal gases. [Consider intermolecular forces.) 1. H2. HF. 3172, CHgF. C1F4 2. HF, CHgF. CFq, 3:2. H2 3. H2. C1H3F, 3:2. C1F4, HF 4. CF4. CHgF, 3:2. HF. H2 5. H2. 372, CF4. CngF, HE' I'_'.DI'I‘EI'_'.t D29 [part 1 of 1} 10 points In an improved version of the gas law._ V is replaced by [V — n. ta}. 'Which of the following would you predict has the largest ta? 1. Ne 2. Ar 3. Xe correct 4. Kr 5. He 030 [part 1 of 1] 10 points In an improved version of the gas law._ P is replaced by (P + 'Which of the following would you predict has the largest o? 1. 03 2. 3:2 3. He 4. H20 correct 5. Ar 3. CH4 [1131 (part 1 of 1] 10 points 1What are all of the intermolecular forces that are responsible for the existence of ice? 1. hydrogen bonding and dipole—dip ole 2. clip ole—clip ole and London forces 3. dipole—dipole, London forces, and hydro— gen boncling correct 4. clip ole—clip ole and ion—ion 5. London forces 002 (part 1 of 1:] 10 points For which of the molecules 3) 03 Bi 002 C) 02 Di 502 will dip ole—dip ole interactions 13 e important? 1. A and B only 2. B and C- only 3. A and C- only 4. B and D only 5. A and D only correct 6. All have dip ole—dip ole interactions. 7. Another combination of compounds 8. None has dip ole—dipole interactions. 9. C- and D only 003 (part 1 of 1:] 10 points Which of the following molecules A] CchOOH C) CH30C-H3 B] CflchQOH D) GH30HO are likely to form hydrogen bonds? 1. A and D only 2. None forms hydrogen bonds. 3. A and B only correct 4. Another combination of compounds 5. B and D only 6. All are likely to form hydrogen bonds. 7. B and C‘- only 3. A and C- only 9. C‘- and D only 004 (part 1 of 1:] 0 points Calculate the ratio of potential energies for an ion—dip ole interaction between LiJr and l{+ and a water molecule. The ionic radius of Li+, K+= and Cl‘ ions are 58 pm. 138 pm: and 181 13111. respectively. 1. 5.66 correct 2. 2 3. 1.33 4. 0.5 5. 1 005 (part 1 of 1:] 10 points Which of HCl or NaCl is likely to have the higher normal boiling point? 1. They are same 2. NaCl 3. HC-l 006 (part 1 of 1:] 0 points Calculate the ratio of potential energies for an ion—dip ole interaction between Li+ and I~I+ and a water molecule. The ionic radius of Li+. K+= and C11— ions are 58 pm, 138 pm: and 181 13111. respectively. 1. 5.66 correct 2. 1.33 3. 2 =1. 1 . 0.5 ‘37! [108 [part 1 of 1:] 10 points Arrange the following molecules H30, NHg. Ar..l\'aC-1 in order of expected increasing boiling points: 1. Ar, NH3: 1-120: NaCl correct 2. 31ng Ar: H30i NaCl 3. NaCl5 H30. NHg= Ar 4. correct answer not given A certain liquid has a meniscus that curves downward in glass. This means that the cohe— sive forces in the liquid are less than the forces between the liquid and the glass. 1. False correct 2. True [109 [part 1 of 1:] 10 points 1What type of infer-molecular forces would you expect to find in a sample of PF3? 1. covalent 2. London 3. H—bonding 4. int erionic 5. dip ole—dip ole correct [110 (part 1 of 1:] 10 points Dispersion (London) forces result from 1. the formation of a loose covalent link— age between a hydrogen atom connected to a very electronegative atom in one molecule and another very electronegative atom in a nei glib oring molecule. 2. attraction between molecules in a liquid and molecules or atoms in a solid surface with which the liquid is in contact. 3. distortion of the electron clout] of an atom or molecule by the presence of nearby atoms or molecules. correct 4. attractive forces between a molecule at the surface of a liquid and those beneath it which are not balanced by corresponding forces from above. 5. the balance of attractive and repulsive forces between two polar molecules. 311 [part 1 of 1:] 10 points What are the strongest intermolecular forces present in a liquid sample of PF5? 1. dispersion correct 2. interionic 3. dipole—dipole 4. hydrogen bonding 5. covalent 012 (part 1 of 1:] ll] points TWhat type of infer-molecular forces would you expect to find in a sample of 803'? 1. dipole—dipole 2. H—bonding 3. dispersion correct 4. int erionic 5. covalent 013 (part 1 of 1] 10 points The forces of attraction between a liquid and a surface are called 1. adhesive forces. correct 2. molecular forces. 3. intramolecular forces. 4. dispersion forces. 5. cohesive forces. Ell-:1 [part 1 of l} 10 points Cohesive forces are forces between molecules within a 1. liquid. correct 2. gas. 3. solid. 4. plasma. Dlfi [part 1 of l] 10 points ‘Which of the following is true? 1. Viscosity increases as the strength of in— termolecular forces increase. correct 2. Vapor pressure increases as the strength of intermolecular forces increases. 3. Vapor pressure is not affected by temper— ature. 4. None of these statements is true. 5. Viscosity increases as temperature in— creases. Dlfi [part 1 of l} 10 points 'Which would you expect to be most viscous at a given temperature? 1. SErg correct 2. C1ngg 3. Cannot predict from the molecular for— mula. 4. CH4 ...
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Exam3_PracticeE_Solutions - 001 [part 1 of 1} 10 points The...

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