Exam3 - Version 297 Exam 3 Sutclie (53120) This print-out...

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Version 297 – Exam 3 – Sutclife – (53120) 1 This print-out should have 30 questions. Multiple-choice questions may continue on the next column or page – Fnd all choices be±ore answering. This exam IS ONLY to be taken by students in the 2-3pm MW² class. DO NOT START THIS EXAM i± you do NOT attend the 2- 3pm MW² class. AVOGADRO’S NUMBER = 6.022 x 10 23 001 10.0 points ²or the reaction 2 HCl + Na 2 CO 3 2 NaCl + H 2 O + CO 2 what volume o± 0 . 45 M HCl solution would be needed to produce 2 . 5 L o± CO 2 at STP? 1. 2.5 × 10 2 mL 2. 1.2 × 10 2 mL 3. 4.5 × 10 2 mL 4. 7.5 × 10 2 mL 5. 2.2 × 10 2 mL 6. 5.0 × 10 2 mL correct Explanation: m HCl = 0 . 45 mol V = 2 . 5 L o± CO 2 ? mL HCl = 2 . 5 L CO 2 × 1 mol CO 2 22 . 4 L CO 2 × 2 mol HCl 1 mol CO 2 × 1 L 0 . 45 mol HCl × 1000 mL 1 L = 496 . 032 mL . 002 10.0 points A drop o± liquid tends to have a spherical shape due to the property o± 1. capillary action. 2. close packing. 3. vapor pressure. 4. viscosity. 5. sur±ace tension. correct Explanation: Molecules on the sur±ace o± a liquid are in³uenced by intermolecular attractions to- wards the interior; these attractions pull the sur±ace layer toward the center. The most sta- ble situation is one in which the sur±ace area is minimal. ²or a given volume, a sphere has the least possible sur±ace area. 003 10.0 points A metal bulb is Flled with 10.2 g o± CHCl 3 and 1.67 g o± CH 4 (two gases). What is the total pressure in the bulb i± the temperature is 345 C and the volume is 50.0 mL? 1. 12.1 atm 2. 193 atm correct 3. 0.107 atm 4. There is no pressure because the metal bulb exerts more ±orce than the gas does. 5. 12,030 atm 6. 107 atm 7. 1450 atm Explanation: n CHCl 3 = 10 . 2 g · mol 119 . 5 g = 0 . 0854 mol n CH 4 = 1 . 67 g · mol 16 g = 0 . 104 mol n total = 0 . 1898 mol V = 50 mL = 0 . 05 L T = 345 C + 273 . 15 = 618 . 15 K Applying the ideal gas law equation, P V = nRT P = nRT V P = (0 . 1898)(0 . 08206)(618 . 15) 0 . 05 = 192 . 554 atm 004 10.0 points What are the strongest inter molecular ±orces present in a liquid sample o± PCl 3 ?
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Version 297 – Exam 3 – Sutclife – (53120) 2 1. hydrogen bonding 2. dipole-dipole correct 3. dispersion 4. covalent 5. interionic Explanation: 005 10.0 points All oF the Following statements, except one, are important postulates oF the kinetic- molecular theory oF ideal gases. Which one is not a part oF this kinetic molecular theory? 1. The average kinetic energy oF the molecules is inversely proportional to the ab- solute temperature. correct 2. The volume oF the molecules oF a gas is very small compared to the total volume in which the gas is contained. 3. The time during which a collision be- tween two molecules occurs is negligibly short compared to the time between collisions.
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This note was uploaded on 12/11/2009 for the course CH 301 taught by Professor Fakhreddine/lyon during the Spring '07 term at University of Texas at Austin.

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Exam3 - Version 297 Exam 3 Sutclie (53120) This print-out...

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