| Quiz 15 Problems 1, 2, 3, 4, 5, 6, 10, 17, 18, 29, 30, 35, 36, 37, 42, 43 |
| TURN IN: 2, 4, 6, 10, 18, 36, 42 |
| 2. Work = P·(change in V) P = 1.013x10 5 N/m2. Q = W + (change in U); find (change in U). |
| 4. Study figure 15-8. There are some differences. In this problem, # We start with an isobaric compression at some constant pressure from the first volume to the second volume. This motion is leftward horizontally since the pressure is constant. # Then follows an isothermal expansion to the first volume and to a lower pressure. This motion is downward along the isothermal curve. # Finally, at constant volume, the pressure rises vertically along a straight line to the original pressure. |
|
6. (a) W = 0 (b) Q = W + (cbange in U) |
| 10. (a) Work (a to b) = 0; Work (b to c) = P·(change in V). Please convert atm; 1 atm = 1.013x10 5 N/m2. 1 L = 10 - 3 m3. Add both works. (b) Change in U(a to c) = 0 since the total change in temperature = 0. Remember, change in U = (3/2)nR(Tc - Ta) for an ideal monatomic gas and in general depends only on the change in temperature. Since (Tc - Ta) = 0, change in U = 0. (c) Q (a to c) = W (a to c) + change in U(a to c) = W (a to c) which you know from part (a). |
| 18. efficiency = 1 - (QL/QH) . QH is given and you can find QL from the relationship: QH = W + QL . You call also find the efficiency directly: efficiency = W/QH . |
| 36 and 42 were really covered in class. Read example 15-15. More hints later on these . |