Exam03answers pg1

Exam03answers pg1 - maintaining the same pressure, the...

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This print-out should have 22 questions. Multiple-choice questions may continue on the next column or page – fnd all choices beFore answering. The due time is Central time. 001 (part 1 oF 1) 10 points Which would you expect to be most viscous? 1. C 8 H 18 at 50 C 2. C 4 H 8 at 30 C 3. C 4 H 8 at 50 C 4. C 8 H 18 at 30 C correct Explanation: 002 (part 1 oF 1) 12 points What is the molar mass oF a 0.710 g sample oF gas that occupies a volume oF 0.900 L at a pressure oF 0.527 atm and a temperature oF 49.0 C? Correct answer: 39 . 5726 g / mol. Explanation: m = 0 . 71 g P = 0 . 527 atm T = 49 . 0 C + 273 . 15 = 322 . 15 K V = 0 . 9 L M = ? M = m RT P V = (0 . 71 g) ( 0 . 08206 L · atm mol · K ) (322 . 15 K) (0 . 527 atm) (0 . 9 L) = 39 . 5726 g / mol 003 (part 1 oF 1) 12 points How many atoms oF argon occupy 1 mL iF the temperature is 300 C and the pressure is 1 . 00 × 10 - 3 Torr? 1. 2 . 80 × 10 - 11 2. 2 . 44 × 10 19 3. 1 . 68 × 10 13 correct 4. 3 . 22 × 10 13 5. 1 . 28 × 10 16 Explanation: 004 (part 1 oF 1) 10 points A sample oF ideal gas occupies 10.0 L at 25 C. IF the temperature is increased to 125 C while
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Unformatted text preview: maintaining the same pressure, the volume will be 1. 1201 L. 2. 13.4 L. correct 3. 7.5 L. 4. 50 L. Explanation: T 1 = 25 ◦ C + 273 = 298 K V 1 = 10.0 L T 2 = 125 ◦ C + 273 = 398 K Charles’ law relates the volume and abso-lute (Kelvin) temperature oF a sample oF gas: V 1 T 1 = V 2 T 2 V 2 = V 1 T 2 T 1 = (10 . 0 L) (398 K) 298 K = 13 . 4 L 005 (part 1 oF 1) 10 points A sample oF a gas occupies 3080 milliliters at 20.0 ◦ C and 4549 torr. What volume would it occupy at the same temperature and 263 torr? Correct answer: 53273 . 5 mL. Explanation: P 1 = 4549 torr P 2 = 263 torr V 1 = 3080 mL Applying Boyle’s Law, P 1 V 1 = P 2 V 2 V 2 = P 1 V 1 P 2 = (4549 torr) (3080 mL) 263 torr = 53273 . 5 mL 006 (part 1 oF 1) 10 points What volume oF hydrogen gas (at STP) would be required to produce 1.00 mole oF HCl?...
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This note was uploaded on 01/23/2011 for the course CH 301 taught by Professor Fakhreddine/lyon during the Spring '07 term at University of Texas.

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