Cengel & Boles -- Chapter 2 questions

2-16C Can the enthalpy of a pure substance at a given state be determined from a knowledge of u, P, and v data? How?

Can this be done without using table lookup?

2-19C Is it true that it takes more energy to vaporize 1kg of saturated liquid water at 100 C than it would to vaporize 1kg of saturated liquid water at 120 C?

2.25 complete the following table for H2O.

 T, C P, kPa v, m3/kg Phase description 50 4.16 Saturated mixture 200 Saturated vapor 250 400 110 600

2-33 The average atmospheric pressure in Denver (elevation = 1610m) is 83.4 kPa. Determine the temperature at which water in an uncovered pan will boil in Denver.

2-43 A piston-cylinder device initially contains 50L of liquid water at 25 C and 300 kPa. Heat is transferred to the water at constant pressure until the entire liquid is vaporized.

Build a system in CP to answer the following questions:

(a) what is the mass of the water?

(b) what is the final temperature?

(c) determine the total enthalpy change

(d) show the process on a T-v diagram with respect to saturation lines.

2-56 A rigid tank contains 10kg of air at 150kPa and 20 C. More air is added to the tank until the pressure and temperature rise to 250 kPa and 30 C, respectively. Using CP, determine the amount of air added to the tank.

2-57 An 800-L rigid tank contains 10 kg of air at 25 C. Determine the reading on the pressure gage if the atmospheric pressure is 97 kPa.