# HW10answers - Cheung, Anthony Homework 10 Due: Nov 18 2006,...

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Unformatted text preview: Cheung, Anthony Homework 10 Due: Nov 18 2006, midnight Inst: McCord 1 This print-out should have 22 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. The due time is Central time. 001 (part 1 of 1) 10 points Work is 1. potential energy. 2. organized molecular motion. correct 3. chaotic molecular motion. 4. kinetic energy. 5. heat. Explanation: Work is organized molecular motion since it is displacement of a solid against a force. 002 (part 1 of 1) 10 points On January 1, 2001, a bookstore had 266,478 booksinstock. OnFebruary1, 2001, thesame bookstore had 257,814 books in stock. What is the value of (books) for the bookstore during that period? Correct answer:- 8664 books. Explanation: B f = 257 , 814 books B i = 266 , 478 books B = B f- B i = 257 , 814 books- 266 , 478 books =- 8664 books Thus the bookstore had 8664 fewer books on February 1. 003 (part 1 of 1) 10 points A rubber ball resting on a table has energy by virtue of its height above the ground ( E = g m h where g is gravitational acceleration, m is mass and h is height in meters). When the ball falls off of the table, its potential energy is converted to kinetic energy until it hits the floor and stops bouncing. If the first law of thermodynamics is true, where did the energy go? 1. The energy was lost to friction with the air and converted to heat every time it hit the floor. correct 2. It was converted to kinetic energy and lost. 3. No energy was lost, the ball has the same amount of energy as when it began. 4. The energy was converted back to poten- tial energy. Explanation: The ball transferred its energy as heat due to friction with the air and impact with the ground. 004 (part 1 of 1) 10 points A property that determines the direction of heat flow is 1. temperature. correct 2. calorie. 3. combustion. 4. entropy. Explanation: Heat flows spontaneously from a hotter body to a colder body. In other words, heat flows from a body of high temperature to a body of lower temperature. 005 (part 1 of 1) 10 points If the products of a reaction have a higher energy than the reactants, then the reaction 1. must be spontaneous. 2. is not spontaneous. 3. is exothermic. 4. is endothermic. correct Explanation: Cheung, Anthony Homework 10 Due: Nov 18 2006, midnight Inst: McCord 2 Energy must flow into the system for the products to have a higher energy than the re- actants. H will be positive and the reaction will be endothermic. 006 (part 1 of 1) 10 points A chemical reaction takes place in a container of cross-sectional area 100 cm 2 . As a result of thereaction, apistonispushedoutthrough19 cm against an external pressure of 658 torr....
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## HW10answers - Cheung, Anthony Homework 10 Due: Nov 18 2006,...

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