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Unformatted text preview: ENGR 225 Name _______________________ September 29, 2006 Recitation: 8:30___;10:15; ___1:15 Short answer (2 pts .each, for T/F and multiple choice circle the best answer of the choices given , fill in the blank must be completed with a meaningful word or phrase) 1. Both energy and mass can cross the boundaries surrounding a ______________________. 2. T F The size and shape of a thermodynamic system, or control volume, is entirely up to the person attempting to solve the problem. 3. A thermodynamic state is defined by the a) process used to arrive at the state b) values of the thermodynamic variables at that state c) cost per unit volume of the working fluid used in the process d) all of the above e) none of the above 4. A ______________ is a macroscopic characteristic of a system. 5. T F Local equilibrium means that processes are slow enough that there are no internal gradients. 6. The components of equilibrium include a) phase b) mechanical c) thermal d) all of the above e) none of the above 7. In the MKS system, kinetic energy per unit volume has units of ______________________. 8. T F Intensive properties do not depend on the extent of mass of the substance or system under consideration, but extensive properties do. 9. Pure substances a) include all of the atomic elements b) can change phase state c) must be of homogeneous and unchanging chemical composition d) all of the above e) none of the above 10. The __________________ principle combined with the NIST software allows us to determine the entropy, enthalpy, and specific volume for a given material if we know the temperature and pressure. 11. T F Enthalpy and entropy are the same thing expressed two different ways for convenience. 12. In the expression ! = T T p ref dT c T h ) ( , the symbol h refers to a) heat transfer coefficient b) enthalpy c) head loss 13. A plot of the processes that form a thermodynamic _______________ must form a closed loop no matter which two thermodynamic variables are considered. QUESTIONS 14 - 17 refer to the above figure for Propane produced using the NIST Software. (Each tick mark on the vertical axis corresponds to an index of 1 MPa.) 14. T F A gas at 470 K and 1 MPa can be isothermally compressed to any higher pressure without ever forming a two phase mixture. 15. The specific volume at the critical point is closest to a) 2 m 3 /kmol b) 0.9 m 3 /kmol c) 0.2 m 3 /kmol 16. Keeping in mind the logarithmic nature of the axes, place a mark on the figure to indicate a mixture with a quality of 0.5 at a pressure of 2 MPa. 17. T F If a quantity of propane that is originally at a specific volume of 1 m 3 /kmol and 320 K, is isothermally compressed to one tenth of its original volume the pressure will stay constant....
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