ECHE 311-SPRING 2015
Quiz 2
(1) Calculated values for V and Z for isopropanol vapor at 200oC and 10 bar by
 The ideal gas equation
 Virial Eq. 3.37
 Virial Eq. 3.39
are:
Z
V (cm3mol-1)
IGE
1
3,934
Eq. 3.37
0.9014
3,546
Eq. 3.39
0.8866
3,488
(a) Explain why calculated values for Z and V using Eq. 3.37 and 3.39 when compared
with those calculated by IGE decrease by 1,7 and 13 % percent, respectively.
(b) Which of the above values more accurately estimates the ispopropanol vapor volume.
25 points
1
(2) The acentric factor is defined at Tr=0.7 is:
  1.0  log( Prsat )Tr
Explain when Zo in Pitzer correlation
Z  Z o  wZ 1
becomes identical to Z.
25 points
2
3. Explain the compressibility-factor graph for methane.
25 points
3
(4) Identify which of the relationships given bellow is Lee /Kesler correlation at constant Tr?
(a) ( Z) vs Pr
(b) (Zo) vs Pr
(c) (Z1) vs Pr
(d) (ZoZ1) vs Pr
25 points
4