Midterm Test 2 CHEM 131 - Spring 2009- Answers

Midterm Test 2 CHEM - CHEM 131 Midterm Test 2 Answer Key 1 Label the following statements as true or false(10 F T T F T F F F T F It is easier to

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CHEM 131 Midterm Test 2 Answer Key 1. Label the following statements as true or false. (10) It is easier to drink water through a straw at the top of Mount Everest than at sea level. F A balloon filled with helium will expand as it rises in the atmosphere. T When a gas expands at constant pressure, its temperature will rise. T Heat is produced by the collision of gas molecules against one another. F When a gas is heated, the molecules of gas collide with one another more often. T When a gas contracts the system does work on the surroundings. F When using a constant pressure calorimeter, the change in enthalpy cannot be directly measured. F The internal energy E is easy to measure. F The unit (L atm) is a unit of energy. T When heat is absorbed by a system from its surroundings, the sign of q is negative. F 2. A rubber ball full of helium gas has a volume of 1.000 L and a pressure of 29.812 atm when immersed in an ice-water bath at 0 °C. When immersed in boiling liquid nitrogen the same rubber ball has a volume of 435 mL and a pressure of 1.967 x 10 3 kPa. Calculate the boiling point of nitrogen in °C. (12) Initial PV = nRT T = 0 + 273.15 K (2) (29.812 atm)(1.000 L) = nR(0 + 273.15 K) Final P = (1967 kPa)(1000 Pa/1 kPa)(1 atm/101325 Pa) = 19.413 atm (2) V = 435 mL = 0.435 L (1) (19.413 atm)(0.435 L) = nRT Divide final by initial: T = (19.413 atm)(0.435 L)(0 + 273.15 K) / (29.812 atm)(1.000 L) = 77.373 K (4) or
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This note was uploaded on 02/18/2010 for the course WA 457 taught by Professor Ow during the Spring '10 term at PA Culinary.

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Midterm Test 2 CHEM - CHEM 131 Midterm Test 2 Answer Key 1 Label the following statements as true or false(10 F T T F T F F F T F It is easier to

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