كتاب (نماذج أسئلة الإمتحان التنافسي/ إعداد علي إبراهيم الموسوي)
الجزء السابع والخمسون:
ماجستير لغة عربية كلية العلوم الإسلامية جامعة كربلاء ... ماجستير هندسة تقنيات المساحة الكلية التقنية الهندسية/ بغداد ... ماجستير علم نفس قسم العلوم التربوية والنفسية كلية التربية جامعة البصرة ... ماجستير لغة عربية/أدب قسم اللغة العربية كلية التربية جامعة البصرة ... دكتوراه الفقه وإصوله قسم علوم القرآن والتربية الإسلامية كلية التربية للعلوم الإنسانية جامعة تكريت ... ماجستير هندسة كيمياوية كلية الهندسة جامعة تكريت.
24. اﻟﺮﺣﯿﻢ اﻟﺮﺣﻤﻦ ﷲ ﺑﺴﻢ
ﺗﻜﺮﯾﺖ ﺟﺎﻣﻌﺔ–اﻟﮭﻨﺪﺳﺔ ﻛﻠﯿﺔ-اﻟﻜﯿﻤﯿﺎوﯾﺔ اﻟﮭﻨﺪﺳﺔ ﻗﺴﻢ
اﻟﺪراﺳﻲ ﻟﻠﻌﺎم اﻟﻤﺎﺟﺴﺘﯿﺮ ﻟﺪراﺳﺔ اﻟﻤﺘﻘﺪﻣﯿﻦ ﻟﻠﻄﻠﺒﺔ اﻟﺘﻨﺎﻓﺴﻲ اﻻﻣﺘﺤﺎن اﺳﺌﻠﺔ2013–2014
Part One: Choose the correct answer in the following: (60% , 2 marks for each question)
1. The average molecular weight of a gas of the following composition is:
CH4 30% , H2 10% , N2 60% [M.wt: CH4=16 , Mwt. H2 = 2 , Mwt. N2 =28].
a) 18.8 b) 20.7 c) 21.8 d) 23.7
2. In SI units, the nano prefix multiplication factor is:
a) 1,000,000,000 b) 0.000000001 c) 1,000,000 d) 0.000001
3. A typical distillation column is shown in fig. below. The amount of distillate per kg of feed is:
a) 0.25 b) 0.275 c) 0.375 d) 0.5
4. The dehydrogenation of ethane in a steady state continuous reaction is represented in the figure,
below. The fractional conversion of ethane (C2H6) is:
a) 0.3 b) 0.4 c) 0.5 d) 0.6
5. The reading of the pressure gauge is 7.9 kPa. The density in kg/m3
of the fluid is :
(a) 800 (b) 900 (c) 1000 (d) 1100
6. The water flowrate Q3 in m3
/hr is about ;
(a) 1 (b) 1.5 (c) 2 ( d) 2.5
7. The column used for liquid dispersion in a continuous gas phase is:
a) Packed b) Pulse c) Bubble cap d) Sieve plate
8. Which of the following is the most suitable for extraction in a system having very low density
difference ?
a) Mixer-settler extractor b)Centrifugal extractor c)Pulsed extractor d)Packed extractor
Feed
35% EtoH
65 % H2O
Distilate
85% EtoH
15 % H2O
Waste
5% EtoH
95 % H2O
reactor
100 mol/hr
C2H6
x mol H2/hr
60 mol C2H6/h
y mol C2H4/h
Air
Fluid
1 m
PG
u1=3 m/s
d1= 20 mm
u2=3 m/s
d2= 10 mm
Q3=? m3
/hr
d3= 15 mm
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25. 9. Overall efficiency of the distillation column is
a) the ratio of number of ideal plates to actual plates
b) the ratio of number of actual plates to ideal plates
c) same as the Murphree efficiency
d) always more than the point efficiency
10.Relative humidity is the ratio of the
a) partial pressure of the vapour to the vapour pressure of the liquid at room temperature
b) partial pressure of the vapour to the vapour pressure of the liquid at gas temperature
c) actual humidity to saturation humidity d) none of these
11.The equipment frequently used for adiabatic humidification-cooling operation with recirculating
liquid is
a) natural draft cooling tower b) induced draft cooling tower c) spray chamber
d) none of these
12.A catalyst
a) initiates a reaction b) lowers the activation energy of reacting molecules
c) is capable of reacting with any one of the reactants
d) can not be recovered chemically unchanged at the end of a chemical reaction
13.Which of the following is the most suitable for very high pressure gas phase reaction ?
a) Batch reactor b) Tubular flow reactor c) Stirred tank reactor d) Fluidised bed reactor
14.Pick out the wrong statement pertaining to space velocity of flow reactors
a) The unit of space velocity is (time)-1
b) The space velocity of 3 hr-1
means that three reactor volumes of feed at specified conditions are being
fed into the reactor every hour
c) The space velocity of 3 hr-1
means that one third reactor volume of feed at specified conditions are
being fed into the reactor
d) none of these
15.A reversible liquid phase endothermic reaction is to be carried out in a plug flow reactor. For
minimum reactor volume, it should be operated such that the temperature along the length
a) decreases b) increases c) is at the highest allowable temperature throughout
d) first increases and then decreases
16.The second law of thermodynamics says that
a. energy cannot be created or destroyed.
b. heat flows from a hotter to a colder surface.
c. for every action there is an opposite and equal reaction.
d. systems tend to gravitate toward a condition of greater order.
17.In an isothermal process
a. dU=0 b. dH=0 c. dT=0 d. All
18.Which of the following statements is true
a) The work done in reversible expansion is less than the work done in irreversible expansion.
b) The work done in reversible expansion is equal to the work done in irreversible expansion.
c) The work done in reversible expansion is greater than the work done in irreversible expansion.
d) All.
e)
19.The amount of heat exchanged between system and surroundings under constant pressure is called
a. Entropy b. Free energy c. Internal energy d. Enthalpy
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26. 20.Choose the incorrect statement
a. Open systems can exchange both energy and matter with its surroundings.
b. Closed systems can only exchange energy and do not exchange matter with its surroundings.
c. Isolated systems can exchange energy and matter with its surroundings.
d. None.
21.The transfer function for an ideal proportional plus derivative controller (reset time T) is
a) b) c) KC d)
22.The thermometer is exemplifies a system of order:
a) zero b) first b) second d) third
23.Response of a linear control system for a change in set point is called
a) Frequency response b) Transient response b) Servo system d) Regulator system
24.A non-linear chemical system is exemplified by a/an
a) Isothermal CSTR b) Mixing tank c) Non-isothermal CSTR d) None of these
25.Newton's law of cooling is
a. .
26.The rate of heat transfer through a unit thickness of the material per unit area per unit temperature
difference is called
a) Thermal conductivity b) Heat transfer coefficient c) Stefan-Boltzmann constant
27.Centrifugal acceleration is:
a) greater than gravity acceleration b) less than gravity acceleration c) same
28.A wet solid is dried over a long period of time by unsaturated air of nonzero constant relative
humidity. The moisture content eventually attained by the solid is termed as the
a) unbound moisture content b) bound moisture content
c) free moisture content d) equilibrium moisture content
29.In a double pipe counter-current heat exchanger, the temperature profiles shown in the figure as
observed. During operation, due to fouling inside the pipe, the heat transfer rate reduces to half of
the original value. Assuming that the flow rates and the physical properties of the fluids; do not
change, the LMTD (in °C) in the new situation is
a) 0 b) 20 c) 40 d) indeterminate
30.The forced convective heat transfer coefficient for a hot fluid flowing over a cool surface is 225
W/m2
°C for a particular problem. The fluid temperature upstream of the cool surface is 120 °C,
and the surface is held at 10 o
C. Determine the heat transfer rate per unit surface area from the
fluid to the surface.
a) 247500 b) 24750 c) 2475 d) 247.5
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27. Part Two: Answer the following questions : (40% , 4 marks per each question)
1. Consider the following pair of reactions
A B (desired ) A C (undesired)
100 moles of A are fed to the reactor and the final product contains 10 moles of A and 15 moles of C.
Calculate :
a) The fractional conversion of A b) The yield of B based on feed
c) The yield of B based on reactant consumption d)The selectivity of B relative to C
2. What is the volumetric flow rate of water as measured by an orifice plate flowmeter , d1=400 mm ,
do=50 mm , h= 20 mm , CD=0.65 , ρw=1000 kg/m3
, ρHg=13600 kg/m3
3. During a chemical reaction, the following concentrations of species A at various times were observed.
Determine:
a) The reaction order and reaction rate constant, k b)The concentration of A after 20hrs.
Time, hours Concentration, mg/L
0 50.8
7.5 32
15 19.7
22.5 12.3
30 7.6
4. Determine the diffusivity of CO2 (1), O 2 (2) and N2 (3) in a gas mixture having the composition: CO2
: 28.5 %, O2 : 15%, N 2 : 56.5%,
The gas mixture is at 273 k and 1.2 * 10 5
Pa. The binary diffusivity values are given as: (at 273 K)
D 12 P = 1.874 m 2
Pa/sec , D 13 P = 1.945 m 2
Pa/sec , D 23 P = 1.834 m 2
Pa/sec
5. Draw the interacting two tanks system in series and non-interacting two tanks system in series.
6. Explain with equations the third law of thermodynamics.
7. Describe the cracking process with a proper flow diagram.
8. Determine the steady state rate of heat transfer per unit area through a 4.0 cm thick
homogeneous slab with its two faces maintained at uniform temperatures of 38 °C and 21 °C. The
thermal conductivity of the material is 0.19 W/m-K
9. Define :- API gravity, Aniline point, Octane number, LPG
10. Calculate the power of propeller mixer of water at 500 RPM speed and 50 mm impeller diameter.
d1
do
h
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28. University of Tikrit / College of Engineering Date: 2 / 9 /2012
Chem. Eng. Dept. Time: 3 hrs
2012-2013 M. Sc. Qualification Exam
Part One: Choose the correct answer of the following: (60% , 30 questions, 2 marks per each question)
1. The volume percentage of O2 in air is 21%, and the weight percentage of O2 in air is about:
a) 21% b) 22% c) 23% d) 24%
2. The weight percentage of chlorine in common salt NaCl is about : (Na=23, Cl=35.5)
a) 61% b) 62% c) 63% d) 64%
3. The rate of heat transfer (kW) to methanol evaporator at its boiling point to generate 1500
g/min saturated vapor is about: [ heat of vaporization is 35.8 kJ/mol , Mw=32 ]
a) 26 b) 27 c) 28 d) 29
4. The number 0.0000055 is equivalent to :
a) 5.5x107
b) 5.5x10-7
c) 55x107
d) 55x10-7
5. The power of the pump required (kW) for water flowrate of 20 m3
/h, 70 m head, and 64%
efficiency is about:
a) 5 b) 6 c) 7 d) 8
6. The extreme limit of the absolute vacuum pressure (atm) is:
a) 1 b) 0 c) -1 d) -2
7. The flowrate (m3
/h) from a 5 mm nozzle at a bottom of a tank containing water of constant 5 m
height, neglecting friction loss is about:
a) 0.4 b) 0.5 c) 0.6 d) 0.7
8. The pressure drop (N/m2
) in a horizontal pipe of oil flowrate =53 m3
/h, pipe diameter d=100
mm, and length L=10 m is about: [oil density =800 kg/m3 and viscosity= 100 cP]
a) 60 b) 600 c) 6000 d) 60000
9. Air flow in a pipe d=100 mm at 25 o
C and 1 atm. A pitot tube at the center show a manometer
reading 100 mm H2O, CD=0.98. Air flow rate (m3
/hr) is about:
a) 90 b) 900 c) 9000 d) 90000
10. LPG containing mainly:
a) Methane & Ethane b) Ethane & Propane c) Propane & Butane d) Butane & pentane
11. The molecular weight of heavy crude oil (API = 30, Mean average b.pt=642 o
F ) is about:
a) 50-100 b) 100-200 c) 200-300 d) 300-400
12. The viscosity (cst) of heavy crude oil (API = 30, Mean average b.pt=642 o
F ) is about:
a) 1-10 b) 10-20 c) 20-30 d) 30-40
13. The Heat transfer coefficient is important parameter in:
a) conduction b) convection c) radiation d) all
14. The more Efficient heat transfer rate is in:
a) laminar b) turbulent c) transition d) same
15. Air at 20◦C blows over a hot plate 50 by 75 cm maintained at 250◦C. The convection heat-
transfer coefficient is 25 W/m2
· ◦C. The heat transfer (kW) is about:
a) 216 b) 21.6 c) 2.16 d) 0.216
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29. 16. One face of a copper plate 3 cm thick is maintained at 400◦C, and the other face is maintained
at 100◦C. The heat transfer (kW/m2
) through the plate is about: [kcopper=370 W/m oC
a) 73000 b) 3700 c) 37000 d) 7300
17. A cylindrical resistor (d=4 mm, L=15 mm) on a circuit board dissipates 0.6 W of power, The
heat flux (W/m2
) on the surface of the resistor is about:
a) 4810 b) 3810 c) 2810 d) 1810
18. By what percentage would the rate of absorption be increased or decreased by increasing the
total pressure from 100 to 200 kN/m2
in the case of the absorption of ammonia from a mixture
of ammonia and air containing 10% of ammonia by volume, using pure water as solvent.
Assume that all the resistance to mass transfer lies within the gas phase.
a) unchanged b) doubled c) 50% reduced d) 50% increased
19. If a fiver-component mixture A–B–C–D-E is to be distilled,
Feed Top product Bottom product
A A
B B
C C C
D D D
E E
the light and heavy keys components respectively are:
a) A & B b) B & C c) C & D d) D & E
20. If a centrifuge is 0.9 m diameter and rotates at 20 Hz, at what speed (Hz) should a laboratory
centrifuge of 150 mm diameter be run if it is to duplicate the performance of the large unit:
a) 29 b) 39 c) 49 d) 59
21. If A rotary filter, operating at 1.8 rpm, filters at the rate of 0.0075 m3
/s. Operating under the
same vacuum and neglecting the resistance of the filter cloth, at what speed (rpm) must the filter
be operated to give a filtration rate of 0.0160 m3
/s?:
a) 7.2 b) 8.2 c) 9.2 d) 10.2
22. Two litres of an ideal gas at a pressure of 10 atm expands isothermally into vacuum until its
total volume becomes 100 litres.The amount of heat (J) absorbed in the expansion is:
a) 2.303 b) 100 c) 90 d) None
23. Ten litres of an ideal gas at a pressure of 10 atm expands isothermally against a constant
pressure of 1 atm. until its total volume becomes 100 litres.The work done in the expansion is:
a) -90 L-atm b) -10 L-atm c) -23.03 L-atm d) -230.3 L-atm
24. In a process, 800 J of heat is absorbed by a system and 350 J of work is done by the system. The
change in internal energy (J) for the process is:
a) -350 b) -450 c) 350 d) 450
25. The density of O2 at 30 o
C and 10 atm is about (kg/m3
) :
a) 1.3 b) 13 c) 130 d) 1300
26. The amount of heat absorbed by one mole of an ideal gas in an isochoric process to raise the
temperature from 1.1 o
C to 11.1 o
C is 120 kJ/mol. The Cv and Cp values of the gas in kJ/mol K
will be:
a) 12 kJ & 3.7 kJ b) 10 kJ & 12 kJ c) 12 kJ & 20.3 kJ d) 20.3 kJ & 12 kJ
27. The second law of thermodynamics says that:
a) energy cannot be created or destroyed b) heat flows from a hotter to a colder surface
c) for action there is an opposite and equal reaction d) systems tend to gravitate toward a condition of greater order
28. The rangeability is the ratio of :
a) maximum flow to minimum flow b) maximum controllable flow to minimum controllable flow
c) normal flow to minimum flow d) maximum controllable flow to normal flow.
29. The element in process control loop that regulate the manipulating variable is;
a) Control valve b) Sensor c) Controller d) Transmitter
30. The outlet signal from current/ pneumatic (I/P) convertor in process control loop is equal to :
a) 0 to 10 volt b) 3 to 15 psig c) 4 to 20 mA d) 0 to 100 mV
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30. per each question)Part two: Answer of the following questions : (40% , 10 questions, 4 marks
1. A distillation column is used to separate benzene and toluene mixtures (50 wt% benzene) at 80
ton/hr feed flowrate. The top product is 95 wt% benzene. The benzene recovery is 95 wt%.
Calculate the top flowrate and bottom flowrate and composition.
2. Water-free Oxygen flowrate of 6.00 L/min at 25°C and 1.00 atm is input to humidifier. The
humidified oxygen leaving the humidifier is at 25ºC and 1 atm and relative humidity 60%. How
much water will be evaporated during a day to humidify the oxygen (g/day)? What is the rate of
heat transfer (W) to (or from) the humidifier in order that both the oxygen and the humidifier
remain at 25°C?
[vapor pressure of water at 25ºC is 23.756 mm Hg, heat of vaporization at 25ºC is 2442.5 kJ/kg]
3. The manometer shown below contains three liquids. The densities of the three are: ρ1 =2.0 g/cm3,
ρ2 = 1.0 g/cm3, and ρ3 = 1.6 g/cm3. The one end of the manometer is connected to a vessel filled
with a gas; the other is open to the atmosphere (PB) in Pullman, where the ambient pressure is 710
mm Hg. The inclined leg of the manometer is inclined at an angle of 30° from the horizontal.
What is the pressure (PA) inside the vessel?
4. Draw a typical flow diagram of modern petroleum refinery plant.
5. How can you design a Heat Exchanger? Put the main equations, describe briefly?
6. Oxygen bubble of 1 mm diameter is injected into stirred water. After 7 minutes, the bubble is 0.54
mm in diameter. What is the mass transfer coefficient? [ for sphere V=4πr3
/3 , A=4πr2
]
7. Calculate the terminal velocity of a material ball, 0.1 mm diameter and of density 1500 kg/m3
in
an oil of density 900 kg/m3
and viscosity 50 mNs/m2
. Assuming Stokes’ law is valid
8. Explain with equations the adiabatic and isothermal processes.
9. Draw the first order plus time delay system, with its transfer function
10. Draw the temperature control loop of a heat exchanger.
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