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Unformatted text preview: galloway (jlg4528) – H11: Thermo 1 – mccord – (50960) 1 This print-out should have 15 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. This homework really comes from sections 1 and 2 in Chapter 9. Also refer to your class notes from Dr. McCord. DO con- tinue reading on through section 6 for next week (11/7-11/11). H12 will be a much big- ger homework assignment. Also, WATCH for Learning Modules to be posted over the week- end and due early next week - like on Tuesday morning. 001 10.0 points Work is 1. potential energy. 2. chaotic molecular motion. 3. kinetic energy. 4. organized molecular motion. correct 5. heat. Explanation: Work is organized molecular motion since it is displacement of a solid against a force. 002 10.0 points If a process is carried out at constant pressure P and the volume V of the system decreases, then Δ V is (negative, positive) and the work w is (negative, positive, zero). 1. negative; negative 2. negative; zero 3. positive; zero 4. negative; positive correct 5. positive; negative Explanation: Δ V = V f − V i < since V i > V f . Thus w = − P Δ V > since Δ V is negative. 003 10.0 points A chemical reaction takes place in a container of cross-sectional area 100 cm 2 . As a result of the reaction, a piston is pushed out through 21 cm against an external pressure of 519 torr. What is the value for w for this reaction? (Sign does matter.) Correct answer: − 145 J. Explanation: 004 10.0 points The definition of internal energy is Δ U = q + w . Which of these three values are state func- tions? 1. q and w , but only at constant volume 2. Δ U , but only at constant volume 3. q and w only 4. Δ U only correct 5. Δ U , q , and w Explanation: 005 10.0 points A 100 W electric heater (1 W = 1 J / s) oper- ates for 15 min to heat the gas in a cylinder....
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- Fall '11
- Energy, Galloway