Student No.:
~~~~~~~~~~~
CHEE210 Winter 2013
Instructor: Dr. Brant A. Peppley, P.Eng.
Date: Thursday, 28 February 2013
Open Book. Answer all questions on the pages provided. Use the back of pages if necessary being sure to mark
the problem number and section on t~ additional work. Write your name and student number on each riage.
There are three (3) problems and four (6) single-side pages. Complete all problems.
(Time: 55 minutes)
Note: The Equation and Data Sheet with this Quiz includes Fig 3.14 from the text and an excerpt from
the Lee-Kesler Generalized Correlation Tables
Useful Numbers
Gas Constant (watch your units!!)
R = 8.314 J mor 1 K- 1 = 8.314 L kPa mor 1 K- 1 = 82.06 cm3 atm mor 1 K 1 = 0.08206 L atm mor 1 K 1
Conversions
1 atm = 101.4 kPa
1m3 =1000 L
1 tonne = 1000 kg
Temperature (K) =Temperature (°C) ~ 273.15
1. By applying the phase rule answer each of the following questions.
a. For a pure substance where solid, liquid and gas are in equilibrium how many degrees
of freedom are there and how many state variables need to be defined to fully specify
the system.
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b. For a pure substance at equilibrium in the gas phase how many state variables need to
be defined to fully specify.the system.
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Name:
Student No.:
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----------
c. If the degrees of freedom as calculated by the phase rule is zero for a system containing
two species (e.g., water/ethanol) how many distinct phases are present and in
equilibrium?
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d. For,Eure water in equilibrium with its vapour (i.e., steam) at 1.0 atm what is the
f...
temperature of the system?
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Determine Z and V for steam atJ/llKJ![C and~ bar using:
a.) The Ideal Gas Law
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b.) Lee-Kesler tables
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c.) Generalized Pitzer Correlation.
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d.) Check the method that would be the most appropriate, accurate and convenient to use?
Ideal Gas Law
•
Generalized Pitzer Correlation
Lee-Kesler Tables
Pg 3 of6
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Name:
Student No.:
3.
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~~~~~~~~~~~-
The standard air Otto Cycle is commonly used as an idealized representation of the four stroke
internal combustion automobile engine. The reversible Otto cycle consists of four individual
processes to form the cycle. The figure below shows these four processes that make up the
cycle (Source: Northwestern Uni,versity On Line Thermo Design Library)
3
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Step 1:
Step 2:
Step 3:
Step 4:
Reversible adiabatic compression from P 1 to P2
Constant volume heating from Tz to T3
Reversible adiabatic expansion from P3 to P4 (this is called the power stroke)
Constant volume cooling from T4 to T1
Assume that y = 1.4 and Cv = 22.976 J mor 1 K 1and Cv is constant over the range of
conditions. Given that P 1=100 kPa and T1 = 20°C, the maximum temperature T3 = 1500°C and
the volume compression ratio is 8 (i.e., V 1N 2 = 8).
For one mole of air assuming ideal behaviour answer the following .
•
a) Calculate the net work output for one cycle of the engine.
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b) The heat input to the engine for one cycle (Note: This is not the net heat input but just
the heat transferred to the system shown as Qin in the figure above).
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c) The thermal efficiency for the cycle.
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Name:
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Student No.:
~~~~~~~~~
d) The heat that leaves the system (Qout shown in the figure)
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f) The entropy change for each step (L1S12, L1S23, L1S34, L1S41) and the L1Scycle· (Hint: the
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cycle is reversible.)
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