# Exam03answers pg2 - proportional to pressure Explanation...

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H 2 (g) + Cl 2 (g) 2 HCl(g) 1. 5.3 L 2. 22.4 L 3. 11.2 L correct 4. 44.8 L 5. 6.6 L Explanation: n 1 = 1 mol n 2 = 0.5 mol V 1 = 22.4 L 1 mole of an ideal gas at STP (T = 0 C = 273 . 15 K , P = 1 atm) has a volume of 22 . 4 L. If T and P are constant the ideal gas law reduces to V 1 V 2 = n 1 n 2 V 2 = V 1 n 2 n 1 1 mol HCl · 1 mol H 2 2 mol HCl = 0 . 5 mol H 2 V 2 = (22 . 4 L) (0 . 5 mol) 1 mol = 11 . 2 L 007 (part 1 of 1) 12 points If the average speed of a water molecule at 25 C is 640 m · s - 1 , what is the average speed at 100 C? 1. 320 m/s 2. 716 m/s correct 3. 801 m/s 4. 572 m/s 5. 5120 m/s Explanation: 008 (part 1 of 1) 10 points Which describes Dalton’s Law? 1. The volume occupied by a given weight of gas at constant pressure is directly propor- tional to the absolute temperature. 2. The total pressure exerted by a mixture of gases is the sum of the pressures exerted by the individual gases in the mixture. correct 3. The volume occupied by a given weight if gas at constant temperature is inversely
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Unformatted text preview: proportional to pressure. Explanation: Dalton’s Law states that the total pressure exerted by a mixture of ideal gases is the sum of the partial pressures of those gases: P total = P A + P B + P C + ... under constant V , T . 009 (part 1 of 1) 12 points 0.65 moles of O 2 originally at 85 ◦ C is cooled such that it now occupies 8.0 L at 40. ◦ C. What is the Fnal pressure exerted by the gas? 1. 2.09 atm correct 2. 3.12 atm 3. 2.39 atm 4. 0.27 atm 5. 0.87 atm 6. Not enough information is given. Explanation: NOTE: the 85 ◦ C is not needed in the cal-culation. That temperature could have been ANY temperature. T = 40 ◦ C + 273 . 15 = 313 . 15 K V = 8 . 0 L n = 0 . 65 mol Using the Ideal Gas Law, P V = n R T P = n R T V = (0 . 65) (0 . 082058) (313 . 15) 8 . = 2 . 09 atm...
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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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