Problems:

6.18
6.23
6.24
3.35*:	Using the states given in this problem, (a) Find the heat transfer for this process. (b) Determine the entropy change for the R-22 (in kJ/K). (c) If the surroundings are at a constant temperature of -20oC, determine the entropy change for the surroundings (in kJ/K). (d) Find the net entropy change, delta-Snet, for this process (in kJ/K).
3.106*:	Use table A-22 to for this problem, do not use Cpo or Cvo. Assume that the mass of the gas is 1 kg Using the states given in this problem, (a) Find the total heat transfer for this entire process. (b) Determine the total entropy change for the air (in kJ/K). (c) If the surroundings are at a constant temperature of 0oC, determine the entropy change for the surroundings (in kJ/K). (d) Find the net entropy change, delta-Snet, for this entire process (in kJ/K).

Answers:

6.18:	No answers will be given.
6.23:	No answers will be given.
6.24:	1W2 = -471.5 kJ 1Q2 = -2391.8 kJ
3.35*:	(a) 1Q2 = -34.3 kJ (b) delta-SR-22 = -0.1254 kJ/K (c) delta-Ssurr = 0.1356 kJ/K (d) delta-Snet = 0.0102 kJ/K
3.106*:	(a) 1Q3 = -252.44 kJ (b) delta-Sair = -0.5592 kJ/K (c) delta-Ssurr = 0.9247 kJ/K (d) delta-Snet = 0.3655 kJ/K

Hints:

• Read EACH word.
• Draw some pictures (one for each state).
• Write your assumptions
• Write the given information under each picture.
• Write what it is you are to find.
• If necessary, find the phase at each state. (you may need this to find the T-D properties)
• Write write the equations you are to use (or might want to use).
• Solve the problem...
• PLEASE try to be organized.