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Cengel & Boles: Ch 1: 7E(3pts), 11E(4pts), 37E(2pts), 41E(3pts), 78(6pts)
WB1 
Mass, Force and Gravitational
Acceleration  4 pts 

Problem
Statement : 
A closed system consists of 0.5 lbmole of liquid water and occupies a volume of 0.145 ft3. Determine the weight of the system, in lbf, and the average density, in lbm/ft3, at a location where the acceleration of gravity is g = 30.5 ft/s2.


Hints : 
g_{c} is the key.
Ans.: W ~ 8.5 lbf 
WB2 
Absolute and Gauge Pressures  5 pts 

Problem
Statement : 
Tank A lies inside of Tank B, as shown in the figure, below. Pressure gauge A is located inside Tank B and reads 1.4 bar. Both tanks contain air. The manometer connected to Tank B contains mercury (ρ = 13.59 g/cm3). The manometer reading is h = 20 cm, atmospheric pressure is 101 kPa and g = 9.81 m/s2. Determine the absolute pressures inside Tank A and Tank B in kPa.


Hints : 
Careful application of the manometer equation and unit conversions should go a long way toward solving this problem correctly.
Ans.: PA ~ 270 kPa , PA ~ 130 kPa 
Cengel & Boles: Ch 3: 26(4pts),
29E(4pts)  The internal energy of subcooled liquid R134a at 10oF and 100 psia is 15.169 Btu/lbm (using the same reference state as the thermodynamic table in your textbook),
37E(5pts) Do not use T1 = 30oF. Use T1 = 30oF ! Ans: T2 ~ 76.7oF.
53(6pts) in part (d) sketch the process path on a PV Diagram that includes the twophase envelope and relevant isobars,
66(4pts),
83(6pts)  Assume that the air in the tire behaves as an ideal gas, but then check the validity of this assumption. Determine the mass of air bled off and then determine the volume this mass of air would occupy at Patm and 25oC.
WB3 
An Application of Equations of State  10 pts 

Problem
Statement : 
A 0.016773 m^{3} tank contains 1 kg of R134a at 110°C. Determine the pressure of the refrigerant using:
a.) the ideal gas EOS
b.) the generalized compressibility chart
c.) the refrigerant tables
d.) van der Waals EOS
e.) SoaveRedlichKwong EOS 

Hints : 
Properties of R134a:
T_{c} = 374.25 K , P_{c} = 4.067 MPa , MW = 102.03 g/mole , ω = 0.332
This problem is very similar to an example problem that we discussed in class.
Ans.: Ans.: a.) P ≈ 1900 kPa , d.) P ≈ 1600 kPa , e.) P ≈ 1600 kPa 
WB4 
Relative Humidity  5 pts 

Problem Statement : 
On entering a dwelling maintained at 20°C from the outdoors where the temperature is 10°C, a person's eyeglasses are observed not to become fogged. A humidity gauge indicates the relative humidity in the dwelling is 55%. Can this reading be correct? Provide supporting calculations. 

Hints : 
The key to this problem is to assume that the glasses are at 10°C when they come in from the outdoors. 
