2C1 :  Specific Volume of Saturated Mixtures  4 pts 

Calculate the specific volume for the following
situations: a.) Water at 300^{o}C and 72% quality b.) R134a at 50^{o}C and 83% quality c.) Ammonia at 750 kPa and 48% quality 

Read :  This is an exercise designed to drive home the meaning and use of the new concept of the quality of a saturated mixture. It is crucial to remember that if a quality is given, then the system contains a saturated mixture and you probably need to look up properties of both the saturated liquid and the saturated vapor.  
Given:  a.)  Water  T  300  ^{o}C  x  0.72  kg vap/kg tot  
b.)  R134a  T  50  ^{o}C  x  0.83  kg vap/kg tot  
c.)  Ammonia  P  750  kPa  x  0.48  kg vap/kg tot  
Find:  V  ???  m^{3}/kg  for each of the three parts of this problem.  
Assumptions:  None.  
Equations / Data / Solve:  
Part a.)  Data from the Saturation Temperature Table of the Steam Tables at 300^{o}C:  V_{sat liq}  0.0014042  m^{3}/kg  
V_{sat vap}  0.02166  m^{3}/kg  
P*  8587.9  kPa  
The key equation for this problem is the relationship between the properties of a saturated mixture and the properties of saturated liquid and vapor and the quality.  

Eqn 1  
Now, we can plug numbers into Eqn 1 to answer this part of the question.  V  0.01599  m^{3}/kg  
Notice that I kept 4 significan figures in this answer istead of the usual 2 or 3 because there are 4 significant digits in the sat'd liquid and sat'd vapor values. Perhaps I should have only retained 2 significant digits because there only appear to be 2 significant digits in the quality. I have assumed that there are more than 2, really 4 or more, digits in the quality. This may not be a good assumption.  
Part b.)  Data from the Saturation Temperature Table of the R134a Tables at 50^{o}C:  V_{sat liq}  0.00069142  m^{3}/kg  
V_{sat vap}  0.60620  m^{3}/kg  
P*  29.451  kPa  
Now, we can plug numbers into Eqn 1 to answer this part of the question.  V  0.50326  m^{3}/kg  
Significant figures are a bit tricky here.  
Part c.)  Data from the Saturation Pressure Table of the Ammonia Tables at 400 kPa:  V_{sat liq}  0.0016228  m^{3}/kg  
V_{sat vap}  0.16980  m^{3}/kg  
T_{sat}  15.88  ^{o}C  
^{}  
Now, we can plug numbers into Eqn 1 to answer this part of the question.  V  7.7095  m^{3}/kg  
Significant figures are a bit tricky here as well.  
Verify:  No assumptions to verify.  
Answers :  a.)  V  0.015988  m^{3}/kg  b.)  V  0.50326  m^{3}/kg  
c.)  V  7.7095  m^{3}/kg 