Activity 15 The First Law of the Thermodynamics F1003 Physics II ITESM Campus Aguascalientes January-May 2017 Dr. Juan-Manuel CAMPOS-SANDOVAL Name

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1 Activity 15 The First Law of the Thermodynamics F1003 Physics II ITESM Campus Aguascalientes January-May 2017 Dr. Juan-Manuel CAMPOS-SANDOVAL Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) How much work is done by 3.00 mol of ideal gas when it triples its volume at a constant temperature of 127 C? The ideal gas constant is R = J/mol K. A) 15.3 kj B) 9.97 kj C) 1.20 kj D) 12.7 kj E) 11.0 kj 2) In an isochoric process, the internal (thermal) energy of an ideal gas decreases by 50 J. How much work does the gas do during this process? A) 50 J B) 25 J C) -25 J D) 0.00 J E) -50 J 3) In an isochoric process, the internal (thermal) energy of an ideal gas decreases by 50 J. How much heat is exchanged with the gas during this process? A) 50 J B) -25 J C) -50 J D) 25 J E) 0.00 J 4) During an isothermal process, 5.0 J of heat is removed from an ideal gas. How much work does the gas do during this process? A) -5.0 J B) 0.00 J C) 2.0 J D) 10 J E) 5.0 J 5) During an adiabatic process, an ideal gas does 25 J of work. What is the change in the internal (thermal) energy of the gas during this process? A) 25 J B) -25 J C) -50 J D) 0.00 J E) 50 J 1) 2) 3) 4) 5) 1

2 SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. FIGURE ) Referring to Figure 18-2, a substance carried from point A to B absorbs 50. J and finds its internal energy has increased by 20. J. Going from B to C the internal energy decreases by 5. Joules. (a) How much work was done from A to B? (b) How much heat was absorbed from B to C? (c) How much work was done going from B to C? 6) 7) An ideal gas is allowed to expand slowly at constant temperature to twice its original volume. During the expansion, the gas absorbs 200 kj of heat. (a) What is the change in the internal (thermal) energy of the gas during the expansion? (b) How much work does the gas do during the expansion? 7) MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 8) An ideal monatomic gas cools from K to K at constant volume as 831 J of energy is removed from it. How many moles of gas are in the sample? The ideal gas constant is R = J/mol K. A) 2.50 mol B) mol C) 1.50 mol D) 1.33 mol E) 2.15 mol 8) 9) The temperature of an ideal gas in a sealed 0.40-m 3 rigid container is reduced from 350 K to 270 K. The final pressure of the gas is 60 kpa. The molar heat capacity at constant volume of the gas is 28.0 J/mol K. The heat absorbed by the gas is closest to A) 24 kj. B) -24 kj. C) 31 kj. D) -31 kj. E) 0.00 kj. 9) 2

3 10) A compression, at a constant pressure of 190 kpa, is performed on 5.0 moles of an ideal monatomic gas. The compression reduces the volume of the gas from 0.19 m 3 to 0.12 m 3. The ideal gas constant is R = J/mol K. The work done by the gas is closest to A) -33 kj. B) 33 kj. C) -13 kj. D) 13 kj. E) 0.00 kj. 11) A cylinder contains 23 moles of an ideal gas at a temperature of 300 K. The gas is compressed at constant pressure until the final volume equals 0.43 times the initial volume. The molar heat capacity at constant volume of the gas is 24.0 J/mol K and the ideal gas constant is R = J/mol K. The heat absorbed by the gas is closest to A) -94 kj. B) -33 kj. C) 130 kj. D) 94 kj. E) -130 kj. 12) A monatomic ideal gas undergoes an isothermal expansion at 300 K, as the volume increased from 0.03 m 3 to 0.21 m 3. The final pressure of the gas is 60 kpa. The ideal gas constant is R = J/mol K. The change in the internal (thermal) energy of the gas is closest to A) 0.00 kj. B) -25 kj. C) 25 kj. D) -12 kj. E) 12 kj. 13) 3.0 moles of an ideal gas with a molar heat capacity at constant volume of 4.9 cal/(mol K) and a molar heat capacity at constant pressure of 6.9 cal/(mol K) starts at 300 K and is heated at constant pressure to 320 K, then cooled at constant volume to its original temperature. How much heat flows into the gas during this two-step process? A) 120 cal B) 0.00 cal C) -720 cal D) -120 cal E) 710 cal 14) A container with rigid walls is filled with 4 mol of air with CV = 2.5R. How much does the internal (thermal) energy change if the temperature of the air rises from 16 C to 437 C? The ideal gas constant is R = J/mol K. A) 8.75 kj B) 421 J C) 3.5 kj D) 35 kj 10) 11) 12) 13) 14) 3

4 SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 15) The pv diagram shown is for 7.50 moles of an ideal diatomic gas taken through a cycle from a to b to c. The ideal gas constant is R = J/mol K. 15) (a) What is the highest temperature reached by the gas during the cycle? (b) What net work does the gas do during the cycle? (c) How much heat is exchanged with the gas during part bc of the cycle? Does it enter or leave the gas? (d) What is the change in the internal (thermal) energy of the gas during part bc of the cycle? (e) What is the change in the internal (thermal) energy of the gas during the entire cycle? 4

5 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 16) The figure (not to scale) shows a pv diagram for 1.8 g of helium gas (He) that undergoes the process Find the value of V3. The ideal gas constant is R = J/mol K = L atm/mol K, and the atomic weight of helium is 4.0 g/mol. 16) A) 8.6 L B) 34 L C) 69 L D) 17 L 5

6 Answer Key Testname: ACTIVITY_15_F1003 1) E 2) D 3) C 4) A 5) B 6) (a) 30. J (b) -5. J (i.e. released 5. J) (c) zero 7) (a) zero (b) 200 kj 8) D 9) B 10) C 11) E 12) A 13) A 14) D 15) (a) 208 C (b) 4.00 kj (c) 30.0 kj, leaves the gas (d) kj (e) 0.00 J 16) D 6