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CHEMICAL ENGINEERING REVIEW QUESTIONS
NO QUESTION A B C D1 A valve that controls flow by means of a disk or
wedge-shaped dam sliding at right angles to the direction of flow and seating tightly in the valve body is a
gate valve butterfly valve globe valve orifice
2 The friction factor for flow through a pipe with relative roughness of 0.004 at a Reynold's No. of 80,000 is approximately equal to
0.05 0.03 0.03 0.04
3 The equation that relates friction factor and Reynold's No., f=64/Reynold's No. holds for
smooth pipes laminar and turbulent flow
turbulent flow only laminar flow only
4 Oil flows under laminar conditions inside a steam heated copper pipe. The overall heat transfer coefficient is approximately
equal to the heat transfer coefficient of the oil
the average between the heat transfer coefficient of the steam and that of oil
equal to the heat transfer coefficient equivalent to the resistance offered by the pipe
equal to the heat transfer coefficient of the steam
5 In multi-stage liquid-liquid extraction with partially miscible solvents
the extraction must be done to form co-currently in order to minimize the extraction.
the minimum number of stages occur when the operating lines are parallel.
the minimum number of stages occur when the tie line coincides with an operating line.
the amount of solvent used must be enough to form 2 phases.
6 The enrichment of the vapor steam as it passes through the column in contact with the reflux during distillation is called
evaporation stripping rectification fractionation
7 The maximum number of plates for a given distillation system is obtained at
variable reflux maximum reflux minimum reflux optimum reflux
8 The correct unit for the specific rate constant for the reaction A--->B determined to be first order is
square liter/square mol/min
square liter/square mol/square min
mol/liter/min liter/mol/min
9 On one side of a heat exchanger where either a condensing vapor or a boiling liquid is present, the temperature may be assumed to be constant. In determining the logarithmic mean temperature difference the direction of flow will have
large effect little effect no effect significant effect
10 For a cylinder where steady-state radial heat transfer takes place
the heat flux is constant
maximum heat transfer rate occurs at the surface
the heat transfer is constant
the temperature is uniform throughout the cylinder
11 A plate holding a pool of liquid from which rises a vapor whose average composition is in equilibrium with a liquid whose composition is the average of that of the liquid leaving the plate is called
separation plate theoretical plate transition plate bubble plate
12 Crystallization occurs in a solution that is concentrated unsaturated supersaturated saturated13 Mass transfer in a flowing fluid may be correlated
bySherwood, Nusselt and Reynold's No
Peclet, Reynold's and Schimdt No
Sherwood, Reynold's and Schimdt No
Prandtl, Schimdt and Reynold's No
14 The ratio of the average diameter of the feed to the average diameter of the product is the
settling ratio discharge ratio reduction ratio classification ratio
15 The rate of formation of C for the reaction 2A + B ---> C is found to be rate = k(A)(B)
the rate of formation of C is equal to the rate of disappearance of B
the order of reactio is zero
the value of k is independent of the initial concentrations of A and B
the reaction cannot proceed
16 A device for increasing the velocity of a fluid in steady flow is a
nozzle vent orifice venturi
17 In steady-state backmix flow reactor, composition is
not constant throughout the reactor
constant throughout the reactor
a function of time not uniform throughout the reactor and varies from time to time
18 The amount of money obtainable from the sale of used property over and above any changers involved in removal and sale is called
net value salvage value book value market value
19 In fractionation, an increase in reflux ratio increases the number of theoretical plates
decreases the reboiler duty
increases the amount of distillate
increases the condenser duty
CHEMICAL ENGINEERING REVIEW QUESTIONS 1
20 In mass transfer where the solute in the gas phase is very soluble in the liquid phase
the ratio of liquid phase resistance to the overall resistance is close to unity
the gas phase resistance is approximately equal to the total resistance
the gas phase resistance is negligible
the ratio of gas phase resistance to liquid resistance is approximately zero
21 Heat transfer in turbulent flow may be described through an empirical equation correlating
Nusselt, Stanton and Reynold's Nos
Nusselt, Prandtl and Reynold's Nos
Peclet, Stanton and Prandtl Nos
Schimdt, Peclet and Friction Nos
22 Which of the following fittings exhibits the highest pressure drop for the same flow conditions?
90-degree long radius elbow
90-degree standard elbow
45-degree standard elbow
square-corner elbow
23 A chamber into which steam from a high pressure line can be bled during periods of low steam demand from the power plant is called
switching bank vent compressor accumulator
24 Which one of the following pipes has the highest relative roughness?
2" diameter Wrought iron pipe
4" dia Wrought iron pipe
1" dia Drawn tubing 4" dia Riveted steel pipe
25 In steady-state heat transfer through a series of materials with varying resistances, the heat transfer rate
decreases towards the direction of heat transfer
varies with the thermal conductivity of each material
through each material is inversely proportional to the thickness of the material
is constant throughout the series of materials
26 Reactions whereby reactants proceed along several paths and give different products are
polymeric reactions reversible reactions parallel reactions consecutive reactions
27 Which one among the following materials has the best insulating property?
window glass wood air concret
28 An operation where warm vapor mixture is cooled such as by contact with a liquid resulting in condensation and decreased humidity is
evaporation dehumidification humidification extraction
29 The pressure exerted on a plane parallel to the direction of flow of a moving fluid is called
gauge pressure velocity pressure tangential pressure static pressure
30 For mass transfer to take place, there must be a phase change reaction component concentration gradient momentum gradient
31 Water vapor condenses at 1 atm on a tube whose surface tmeperature is at 80 deg F. in analyzing the heat transfer through the condensate film, it is best to evaluate the liquid properties at
212 deg F 80 deg F 113 deg F 146 deg F
32 The diffusity of water in air at 100 deg F in sq.cm./sec is
0.26 0.28 1.48 0.58
33 A fluid flowing at a rate of 25 cubic meters per hour inside a 60 mm I.D. pipe has an average velocity in meter per sec equal to
5.90 2.50 1.50 0.60
34 An equimolar mixture of benzene and toluene is subjected to a single batch distillation. Distillation is discontinued when 60% of the benzene in the feed is distilled. At this instance the bottom product when analyzed shows benzene to be 36.4 mole%. In the distillate, the mole% of benzene is
66.60 58.10 33.40 54.40
35 When 32 kg of methane is burned completely the theoretical oxygen required is
16 kg 64 kg 128 kg 32 kg
36 The standard heat of reaction for the production of water gas, in kcal/gmole, as given by the equation: C(s) + H2O(g) = CO(g) + H2(g) is
32.20 31.40 26.40 57.80
37 A rectangular duct 4 ft x 1.5 ft in cross section carries conditioned air. In determining the pressure drop through the duct the equivalent diameter in ft may be used which in this case is
4.00 2.18 1.50 2.75
38 A gas decomposition reaction has an activation energy of 245 kJ/mol. The rate of reaction can be accelerated by using a platinum catalyst where the activation energy for the resulting catalyzed reactions is lower at 136 kJ/mol. Using Arrhenius' law and assuming the frequency factor remains the same the catalyzed reaction is faster than the original reaction by a factor of
over 100,000 but less than a million
over 100 but less than 200
over 20 million over 2 but less than 3
39 Water at 100 deg F is flowing through a straight 4-in Sch 40 pipe at a rate of 1.0 gal/min. The length of the pipe is 10 ft. The velocity at the center of the pipe in ft per sec is
0.04 0.05 0.05 0.03
40 A metallic rod 2 cm in diameter is used as a heating element. The thermal conductivity is 370
4440000.00 5130000.00 6930000.00 2040000.00
CHEMICAL ENGINEERING REVIEW QUESTIONS 2
J/sec.sq.m.degC. The surface temperature is maintained at 200 deg C. For the center of the rod not to exceed 500 deg C, the maximum volumetric heat generation rate within the metallic rod in J/sec cu.m. must be
41 This is a steady state temperature reached by a small amount of liquid evaporating into a large amount of unsaturated vapor-gas mixture.
wet-bulb temperature
dew point saturation temperature dry-bulb temperature
42 Air, supplied at the rate of 1200 cfm to a refrigerated coil, has a relative humidity of 20% and dry bulb temperature of 150 deg F. The mass flow of dry air entering per minute is
74.30 75.00 75.26 78.50
43 In adiabatic humidification, it is possible to maintain the temperature of water constant since
according to the phase rule, the degrees of freedom is 3
the system can be well insulated from the surroundings
the temperature of the air can also be maintained constant
increase in the humidity of the air is insignificant
44 An air-carbon tetrachloride vapor mixture at 100 deg F dry bulb and 60 deg F wet bulb is heated until the temperature reaches 180 deg F. the final percent relative humidity is about
0.10 0.05 0.02 0.01
45 The portion of water in the wet solid that cannot be removed by the air in its contact is called
free moisture final moisture content equilibrium moisture content
critical moisture content
46 This type of drier is used for drying pasty materials such as wet filter cakes and lumpy solids
rotary drier flash drier tray drier freeze drier
47 In the constant-rate period, the rate of drying is established by
a balance of the heat requirements for evaporation and the rate at which heat reaches the surface
the internal movement of moisture beneath the surface of the solid
air flow perpendicular to the surface of the solid
air flow parallel to the solid surface
48 Unbound moisture in granular and porous solid moves through the intertices of the solid by a mechanism involving
desorption surface tension surface renewal moisture diffusivity
49 Wet solid is to be dried from 40% to 10% in 5 hours under constant drying conditions. The critical moisture content is 20% and the equilibrium moisture content is 7%. All moisture contents are on dry basis. The time needed to dry from 15% to 5% free moisture under the same drying conditions is
0.542 hrs 1.846 hrs 2.129 hrs 3.42 hrs
50 If the rate of drying under constant drying conditions with air at 140 deg F and absolute humidity of 0.03 lb water per lb dry air of unknown mass of solid is given by R=0.5-exp(-60X) [in lb water/hr-sqft], then the equilibrium moisture content (db) of the material is
0.12 0.03 0.01 0.00
51 In drying at the falling rate period, the rate at which moisture is removed from the solid material
remains constant increases with time decreases with time no drying takes place
52 The major problem in diffusion is to promote diffusion of the solute out of the solid and into the liquid. The most effective way of doing this is
to reduce the solid to the smallest size feasible
to use counter current operation
to use cross flow evaporation
to use spray percolators
53 A slurry flaked soybeans weighing 100 kg contains 75 kg inert solids and 25 kg of solution 10 weight % oil and 90% wt solvent hexane. This slurry is contacted with 100 kg pure hexane in a single stage so that the value of retention for the outlet underflow is 1.5 kg of insoluble solid per kg solvent in the adhering solution. The composition of underflow leaving the extraction stage in %wt oil is
0.30 0.80 1.50 2.30
54 Tung meal containing 55% oil is to be extracted at the rate of 4000 lb per hour using n-hexane containing 5% oil as solvent. A countercurrent multiple stage extraction system is to be used. The meal retains 2 lb of solvent per pound of oil free meal while the residual charge contain 0.11 lb oil per lb oil free meal while the product is composed of 15% oil. The theoretical number of ideal stages is
3.00 4.00 5.00 6.00
CHEMICAL ENGINEERING REVIEW QUESTIONS 3
55 The movement of molecules over a substantial distance is associated with the transfer of heat by
convection conduction radiation all of A, B and C
56 The mode of heat transfer that can take place in a vacuum is known as
convection conduction radiation all of A, B and C
57 The overall conductance for a composite material in series is equal to the
sum of the individual conductances
sum of the individual conductivities
inverse of the total resistance
sum of the individual resistances
58 Film and drop are terms associated with boiling condensation evaporation all of A, B and C59 A 6-in Sch 80 steel pipe is carrying glycerin at an
average temperature of 100 deg F. The pipe is uninsulated, and the outside temperature is 30 deg F. The inside film conductance is 1000 Btu/h-ft-degF while the outside film conductance is 3.0 Btu/h-sq.ft.-degF. Determine the heat lost [Btu] per minute from a 75-ft length of the pipe. Glycerine is flowing at 800 gpm.
99.95 415.70 451.70 475.10
60 An oak (k=0.096 Btu/h-ft-degF) door, 30 in wide, 78 in high, and 2 in thick, has 9 glass (k=0.45 Btu/h-ft-degF) windows, each 6 in by 8 in by 1/4 in thick. Determine the amount of heat lost [Btu] each day with a surface-to-surface temperature difference of 80 deg F.
97.00 242.00 5800.00 139200.00
61 Determine the length needed for a simple concentric-tube, parallel flow heat exchanger to transfer heat from hot water to cold water at a rate of 900 W. The heat exchanger consists of two Type K copper (k=386 W/m-degC) tubes. The smaller tube has an inside diameter of 49.8 mm and an outside diameter of 54.0 mm. Assume that both film coefficients are equal to 100 W/sq.m.-degC. The hot water enters at 90 degC and leaves at 50 degC, and the cold water enters at 10 degC and leaves at 40 degC.
185.5 m 11.02 m 5.51 m 4.14 m
62 A saturated solution containing 1500 kg of potassium chloride at 360 K is cooled in an open tank to 290K. If the specific gravity of the solution is 1.2, the solubility of potassium chloride per 100 parts of water is 53.55 at 360K and 34.5 at 290K, calculate the amount of crystals obtained assuming that loss of water by evaporation is negligible.
4301 kg 1500 kg 966 kg 534 kg
63 An evaporator, working at atmospheric pressure, is to concentrate a solution from 5% to 20% solids at the rate of 1.25 kg/s. The solution which has a specific heat of 4.18 kJ/kg-K is fed to the evaporator at 295K and boils at 380K. Dry saturated steam at 240 kPa is fed to the calandria and the condensate leaves at the temperature of the condensing steam. If the heat transfer coefficient is 2.3 kW/sq.m-K, what is the required area of heat transfer surface. The latent heat of vaporization maybe taken as the same as that of water.
55.8 sq.m. 58.5 sq.m. 85.8 sq.m. 88.5 sq.m.
64 2.5 kg/s of a solution at 288K containing 10% dissolved solids is fed to a forward-feed double effect evaporator operating at a pressure of 14 kPa in the last effect. If the product is to consist of a liquid containing 50% by weight of dissolved solids and dry saturated steam is fed to the steam coils, what should be the pressure of the steam? The surface in each effect is 50 sq.m. and the coefficients for heat transfer in the first and second effects are 2.8 and 1.7 kW/sq.m.-K respectively. Assume that the concentrated solution exhibits a boiling point rise of 5 degK, that the latent heat has a constant value of 2260 kJ/kg and that the specific heat of the liquid stream is constant at 3.75 kJ/kgK.
115 kPa 101.3 kPa 14 kPa zero gauge
65 An acetone-air mixture containing 0.015 mol fraction of acetone has the mol fraction reduced to 1% of this value by countercurrent absorption with water in a packed tower. The gas flow-rate G is 1 kg/sq.m-s of air and the water entering is 1.6
10.92 9.12 4.72 3.03
CHEMICAL ENGINEERING REVIEW QUESTIONS 4
kg/sq.m-s. For this system, Henry's law holds and Ye=1.75x, where Ye is the mol fraction of acetone in the vapour in equilibrium with a mol fraction x in the liquid. How many overall transfer units are required?
66 A still has a liquor composition of ortho-xylen 10%, meta-xylene 65%, para-xylene 17%, benzene 4%, and ethylbenzene 4%. How many plates at total reflux are required to give a product of 80% meta-xylene and 14% para-xylene? The data are given as mole percent.
37.00 38.00 39.00 40.00
67 A mixture of alcohol and water with 0.45 mol fraction of alcohol is to be continuously distilled in a column so as to give a top product of 0.825 mol fraction alcohol and a liquor at the bottom with 0.05 mol fraction alcohol. How many theoretical plates are required if the reflux ratio used is 3?
10.00 9.00 8.00 7.00
68 Prepared cottonseed meats containing 35% extractable oil are fed to a continuous countercurrent extractor of the intermittent drainage type using hexane as solvent. The extractor consists of ten sections, the section efficiency being 50%. The entrainment, assumed constant, is 1 kg solution/kg solids. What will be the oil concentration in the outflowing solvent if the extractable oil content in the meats is to be reduced to 0.5% by weight?
72.20 28.70 27.80 22.70
69 0.4 kg/s of dry seashore sand, containing 1% by weight of salt, is to be washed with 0.4 kg/s of fresh water running countercurrent to the sand through two classifiers in series. Assume that perfect mixing of the sand and water occurs in each classifier and that the sand discharged from each classifier contains one part of water for every two of sand (by weight). If the washed sand is dried in a kiln drier, what percent of salt will it retain?
0.49 0.43 0.29 0.25
70 Forty-five pounds per minute of water is heated from 60 to 180 deg F in a 5/8 in., 16 BWG heat exchanger tube. If the steam condensing at 260 deg F, on the outside of the tube gives an hо of 1000 Btu/hr-sq.ft.-degF, calculate the inside heat transfer coefficient [Btu/hr-cu.ft-degF].
2173.00 696.00 577.00 241.00
71 How many cu.ft. per minute of entering air is needed to evaporate 10 lb of water per hour from a rayon, if the air enters at 80 deg F and 25% humidity and leaves at 170 deg F and 55% relative humidity. The operating pressure is 14.3 psia.
12.54 12.68 13.76 16.28
72 Nicotine is to be extracted from water using kerosene. If 100 lb of a 2% nicotine solution is extracted once with 200 lb of kerosene, what percent of the nicotine is extracted? {Equilibrium data: Y[lb nicotene/lb kerosene] = 0.90X [lb nicotine/lb water]}
64.50 54.60 46.50 45.60
73 We must cool 2500 gpm of water from 120 to 80 deg F. A cooling tower, at 70 deg F and 1 atm, is to be designed to operate with entering air of 40% relative humidity. How many gpm of makeup water must be supplied if windage loss is 95% of the amount lost by evaporation.
77.20 150.00 227.20 300.00
74 We wish to build an economical cold room 20 ft square and 10 ft high. The outside temperature is 80 deg F and te room is to be maintained at 0 deg F. The boss has suggested parallel wooden outer and inner walls separated by a 6-in air space. What will be the heat loss [Btu/hr] through each wall?
3537.00 8457.00 11994.00 20451.00
75 A colloidal solution is to be concentrated from 15 to 65% solids. The specific heat of the feed, entering at 50 deg F is 0.93. The pressure of the saturated steam to the evaporator is 10 psia; the condenser
10500.00 35000.00 40130.00 45500.00
CHEMICAL ENGINEERING REVIEW QUESTIONS 5
pressure is 5-in. Hg abs. The steam chest has an overall heat transfer coefficient of 200 Btu/hr-sq.ft.-degF. Water must be evaporated at the rate of 35,000 lb/hr. Neglecting boiling point elevation, what is the steam consumption [lb/hr]?
76 What is the settling time [sec] for galena particles to settle under free settling conditions through 5 ft of water at 50 deg F. Galena is spherical in shape, with specific gravity and 0.01 inch in diameter.
38.10 18.30 13.80 5.00
77 A 10-ft diameter tank with a quick-opening value to a sump has a 10-ft depth of liquid. How long [t in sec] does it take to drain the tank if the valve is assumed to be equivalent to a 4-in diameter orifice? The liquid density is 60 lb/cu.ft.
2951.00 1644.00 1163.00 19.40
78 What size sharp-edged orifice [inches] was in use if a flow of 120 gpm produced a 4-in Hg differential in a 4-in Schedule 40 pipe. The fluid, measured at 60 degF, had a viscosity of 1 cSt and a specific gravity of 1.
2.21 1.35 4.67 2.00
79 Seven hundred gallons per minute of water are being discharged by a centrifugal pump 5 ft above the pump inlet. The inlet pressure is 4-in Hg above atmospheric and the discharge pressure is 29 psia. If the pump has an 8-inch diameter inlet and a 4-inch diameter discharge, calculate the pump efficiency.
63.00 84.00 95.00 100.00
80 Determine the net positive suction head available to a centrifugal pump when the level of water is just at the suction point. The pumped fluid is water at 140 deg F and it is pumped from an atmospheric tank at 250 gpm. The tank suction point is 7 ft above the pump. The piping is 5-in Schedule 40, 10-ft long with two short radius 90 deg elbows. [Use density=61.38 lb/cuft, Pv=2.89 psi, viscosity=0.47 cP]
34.20 27.70 7.00 0.52
81 Water at 60 deg F flows through a 3-inch Schedule 40 pipe. A pitot tube in the pipe shows a 3-inch Hg differential. If the pitot tube is located at the center of the pipe, what is the mass flow rate of the water [lb/s]?
11.61 14.24 31.70 37.10
82 The gas phase irreversible reaction A+B---->C is elementary. The entering flow rate of A is 10 mol/min and is equal molar in A and B. The entering concentration of A is 0.4 mol/L. What CSTR volume [L] is necessary to achieve 90% conversion?
113.00 227.00 851.00 900.00
83 The irreversible zero order gas phase dimerization 2A ----->A2 is carried out in a packed bed reactor with 5 kg of catalyst. The entering pressure is 10 atm and the exit pressure is 1 atm. Pure A enters at a flow rate of 10 mol/min. The reaction is zero order in A. What is the exit conversion?
0.15 0.50 0.75 1.00
84 The gas phase reaction 2A+B----->C is carried out in a PFR. The feed is equal molar in A and B and the entering temperature is 500K and the entering pressure is 16.4 atm. If the exit conversion is x, then the exit concentration of B is
[B]=0.4(1-x)/(1-0.5x)
[B]=0.4(1-x)/(1-1.5x) [B]=0.4(1-0.5x)/(1-x) [B]=0.2
85 Heat is generated in a 2.5 cm square copper rod at the rate of 35.3e6 W/cu.m. The rod is exposed to a convection environment at 20 deg C where the convection heat transfer coefficient is 4 kW/sq.m.-degC. Determine the surface temperature [deg C] of the rod.
75.20 55.20 25.20 20.00
86 A 5cm diameter cylinder is maintained at a constant temperature of 200 deg C and it is "completely enclosed" by a wind tunnel test chamber, walls of which are at 10 deg C. Air at 350K is forced across the cylinder at a velocity of 50 m/s (h=180 W/m-degC). If the surface emissivity of the cylinder is 0.7, determine the total (i.e., convective and radiative) heat transfer from
13.00 272.00 3478.00 3750.00
CHEMICAL ENGINEERING REVIEW QUESTIONS 6
the cylinder [W per meter length].87 A building wall consists of a 6-in of concrete (kc=
0.7 Btu/hr-ft-degF), 2 in of fiber insulating board, and 3/8 in of gypsum board (kg=0.03 Btu/hr-ft-degF). The inside and outside heat transfer coefficients are 2 and 7 Btu/hr-sqft-degF, respectively. The inside temperature is 72 degF and the outside temperature is 20 degF. Determine the overall heat transfer coefficient for this wall [Btu/hr-sqft-degF].
0.03 0.12 0.71 6.01
88 Current is passed through a cylindrical laboratory heater, which has a 3 cm diameter, generating heat at the rate of 20 MW/cu.m. The heater is exposed to a convection environment at 25 degC where the convection heat transfer coefficient is 0.5 kW/sq.m.-degC. Determine its surface temperature [degC].
325.00 300.00 100.00 25.00
89 A straight rectangular fin has a length of 3.5 cm, a thickness of 1.5 mm, and is made of a material characterized by thermal conductivity of 255 W/m-degC. The fin is exposed to a convection environment at 20 degC and h=1.5 kW/sq.m.-degC. Determine the maximum possible heat transfer from this fin for the base temperature of 150 degC.
1500 W 4392 W 13943 W 19343 W
90 A gaseous fuel is composed of 20% methane( CH4), 40% ethane (C2H6) and 40% propane (C3H8), where all percentages are by volume. The volumetric analysis of the dry products of combustion (ie. everything except the water) for this fuel gives 10.6% carbon dioxide (CO2), 3% oxygen (O2), 1% carbon monoxide (CO) and 85.4% nitrogen (N2). Determine the air fuel ratio on a mass basis for this reaction.
1.00 18.00 23.00 33.00
91 Dodecane (C12H26) gas at 25 degC is burned in a steady flow combustion chamber with 20% excess air that enters at -23.15 degC. The products leave the combustion chamber at 500K. Assuming steady operating conditions and complete combustion, determine the required mass flow rate of the dodecane to supply heat at a rate of 1.5 kW [kg/s].
170.00 100.00 38.00 0.04
92 Two rooms A and B of identical volume are connected by an open doorway. The thermostat in the rooms are set so that Ta<Tb. Which room contains more air molecules?
A B both contain the same no of air molecules
93 If the absolute temperature of a gas is doubled, the mean speed of the gas molecules
is doubled. increases 4 times increases by about 40% decreases.
94 When ice cubes melt in a glass of water, the temperature of the resulting mixture of water and ice
increases. decreases. stays constant.
95 In all naturally occurring processes, the entropy of the universe
increases. decreases. stays the same. may increase or decrease.
96 An inventor seeking a patent claims that a building may be comfortably heated in winter by a device that draws heat into the building from the earth, even though the temperature of the earth is lower than the desired temperature inside the building. He further claims that the quantity of heat supplied to the building in a given time period can significantly exceed the work done by the device during the same period. If you were a patent clerk (like the young Albert Einstein), what should be your recommendation about the application?
The application should be rejected because it violates the first law of Thermodynamics.
The application should be rejected because it violates the second law of Thermodynamics.
The application should be rejected because it violates both 1st and 2nd laws of Thermo.
The application should be given full consideration because it does not violate any laws of Thermodynamics.
97 A fixture containing an ordinary incandescent light bulb is connected to a dimmer switch. The dimmer is adjusted so that the temperature of the tungsten filament inside the bulb increases from 1300K to 2600K. The total power radiated by the bulb
doubles. quadruples. increases 8x. increases 16x.
98 A 30 MW geothermal electric power plant uses hot 2.5 e8 2.2 e8 3 e7 5.2 e8
CHEMICAL ENGINEERING REVIEW QUESTIONS 7
steam from the earth at 157 deg C to heat and vaporize isobutane, which turns a turbine that is connected to a generator. The isobutane is subsequently cooled to 27 C using fans and condensed back to a liquid. The overall efficiency of the plant is 40% of the ideal (Carnot) efficiency. How many joules of heat must be released to the atmosphere per second?
99 The material which remains unchanged in a process is
limiting reactant tie substance excess reactant product yield
100 The ratio of the total quantity of a reactant present in the reactor feed of a recycling operation to the quantity of the same reactant entering the operation as fresh feed is the
recycle ratio combined feed ratio reactant ratio fresh-feed conversion
101 The heating value measured when water formed from combustion is in the liquid state.
Gross Calorific Value
Heat of combustion Latent Heat of Condensation
Net Calorific Value
102 In the combustion of solid fuels, the tie element between the feed and the refuse is the
cooked coal ash moisture volatile combustible matters
103 The coal analysis which is based upon the volatilization characteristics of the fuel is
Proximate analysis Modified analysis Ultimate analysis Elemental analysis
104 An Orsat analysis of the flue gas when pyrite is roasted is on a
SO2-free basis SO3-free basis O2-free basis N2-free basis
105 The empirical relation which allows one to compute for the net hydrogen in a given solid fuel is the
Calderwood equation
Theoretical Oxygen Equation
Dulong's formula Oxygen unaccounted for equation
106 The equivalent of 45degTw in the Baume scale is 26.63 28.32 32.48 42.56107 A furnace completely burns coal containing 70%C.
Analysis of the flue gas shows 15% CO2, 4% O2, 81% N2, and no CO. What is the % of the net hydrogen in the coal?
1.20 1.53 2.38 6.13
108 Which has the lowest water content? dew point at 20degC
70% RH absolute humidity of 0.05
60% saturation
109 A contract was made between a buyer and a paper manufacturer for paper containing 5% moisture at PhP450/tonne FOB on specifications that price adjustment will be made if the quality is different. How much should the buyer pay for 1 tonne of paper with 8% moisture content? Freight cost is PhP45/tonne.
PhP 405 PhP 424.26 PhP 434.16 PhP 450
110 One drier will dry a material from 45% moisture (wb) to 20% moisture (db). From here the material enters another drier where the water content is further reduced to give a final product weighing 1000 kg. If the total evporation from both driers is 800 kg, the moisture of the final product is
0.01 0.02 0.03 0.05
111 An experimental oil is used to distill 6000 kg.hr of Athabasta tar sand which analyzes 30% 'heavy oil', 'light oil', and non-volatile matter. If the distillate contains 12 % heavy oil and this constitutes 25% recovery of the component, the weight in kg of the distillate obtained is
2250.00 3750.00 4350.00 6000.00
112 Coal fired in a furnace has a heating value of 13800 Btu/lb and contains 78.05%C and 1.2%S. The proximate analysis shows 4%M, 24%FC, 8%A and the analysis of the refuse shows 8%VCM, 25%FC and 32% ash. Calculate the % of C lost in the refuse.
4.22 8.00 9.50 17.00
113 Ninety grams of ethane and 384 grams of oxygen are fed continuously to a laboratory furnace. The total combustion products collected was 16.2 gmole with no carbon dioxide. However, not all of the ethane was burned due to faulty combustion. The fraction of ethane that was burned is equal to
0.80 0.85 0.90 0.92
114 The furnace at the Bataan refinery is using a fuel gas which contains methane, ethane and 20% nitrogen. The orsat analysis of the combustion products showed 7.8% CO2, 7.4% O2, and 84.8% N2. The gas is burned with excess air. The %
63.25 57.24 51.20 22.76
CHEMICAL ENGINEERING REVIEW QUESTIONS 8
methane in the fuel gas is115 Pyrite containing 78% FeS2 and 22% gangue is
burned with excess air to produce a stack gas with the following analysis: 7.29% SO2, 8.92%O2, 82.44%N2 and 1.35%SO3. If the cinder was found to have a partial analysis of 62.10% Fe2O3, the % of FeS2 lost in the pyrite is
3.52 6.53 7.86 23.10
116 The unit of k for a 1st order elementary reaction is 1/time conc/time 1/conc 1/conc-time117 If the temperature of a chemical reaction is raised
by 10 degC, the rate of reaction is increased by a factor of
4.00 3.00 2.00 1.50
118 The E of a reaction may be lowered by increasing temperature
decreasing temperature
adding a catalyst removing the products of the reaction
119 The mechanism of a reaction can sometimes be deduced from
the activation energy
the temperature dependency of the rate
the net equation the rate law.
120 The equilibrium constant in a reversible chemical reaction at a given temperature
depends on the initial conc of the reactants
depends on the conc of one of the products at equilibrium
does not depend on the initial concentrations
is not a characteristic of the reaction
121 If the volume of a reaction vessel is suddenly reduced to one half its original volume the rate will increase by a factor of
2.00 4.00 8.00 16.00
122 The rate of reaction is not influenced by conc of the reactants
molecularity of the reaction
nature of reactants temperature
123 The net rate of reaction of an intermediate is 0.00 2.00 > 0 <0124 A reaction is known to be first order in A. A straight
line will be obtained by plottinglog Ca vs time Ca vs time log Ca vs reciprocal
time1/Ca vs time
125 If the reaction 2A ---> B+C is second order, which of the following plots will give a straight line?
Ca^2 vs time 1/Ca vs time lof Ca vs time Ca vs time
126 For the reaction A+B ---> 2C, when Ca is doubled the rate doubles, when Cb is doubled the rate increases fourfold. The rate law is
-ra = k Ca^2 Cb^4 -ra = k Ca Cb^2 -ra = k Ca -ra = k Cb^2
127 It states that the rate of a chemical reaction is proportional to the activity of the reactants.
Le Chatelier's principle
Hess' Law Law of Mass Action Second Law of Thermo
128 The half life of a material undergoing second order decay is
proportional to the square of the initial conc
independent of initial conc
proportional to initial conc
inversely proportional to initial conc
129 A fluid flows through 2 CSTR in series. Each reactor has a capacity of 400,000 L and the fluid enters at 100 L per hr. The fluid undergoes a first order decay with a half life of 24 hours. Find the conversion of the fluid.
66.80 74.70 85.30 99.10
130 A first order reaction has a specific rate constant of 3e-3 per sec. The half life is
0.0021 s 100 s 231 s 768 s
131 A certain reaction is 1st order in A. In 30 min, the concentration of A decreases from 0.55 to 0.15 mol/L. The time it will take for A to decrease from 0.35 to 0.15 mol/L is
45.1 min 19.6 min 19.1 min 10.4 min
132 A gas decomposes at 900 degC according to 2A--->2R+S with a rate constant of 1000 cc/gmol-s using pure A. The time it will take to react 80% of A in a batch reactor at 900 degC and 1 atm in min is
3.83 7.43 8.33 9.33
133 Calculate the length of a chlorinating pipe line with diameter of 0.6 m required to kill 95% of the bacteria in waste water flowing at 0.05 cu.m/s. Test shows that 95.33% kill is obtained in 5 minutes when treated with 5 mg/L of chlorine. Chlorine disinfection kinetics is given by the equation: dC/dt = k Ct^1.5 where C = number of bacteria. Assume that the same concentration of chlorine is used in actual treatment operation.
25.36 m 32.5 m 52.63 m 56.23 m
134 The set of data given below is for the parallel reaction: a---k1-->2R, a---k2-->S. At t=0, Ca=15 moles/cuft, Cr = 1 mole/cuft, Cs=1 mole/cuft; At t=1 hr, Cro = 9 moles/cuft, Cs = 3 moles/cuft. The
0.17 0.18 0.34 0.62
CHEMICAL ENGINEERING REVIEW QUESTIONS 9
value of K2 per hour is135 A batch reaction 2D+E----->F has a conversion
factor expressed by the equation r =0.24 t^0.5 where r = conversion factor based on the reactant E; t = time in hours which ranges from 0.5 to 16 hours per batch depending upon the process variables. The average molecular weight of the feed is 60 and a density of 1.4 g/cc. The feed consists of 2 kgmole of D and 1 kgmole of E. The charging, cleaning and discharging time per batch is 2.5 hrs and the volume of the reactor is twice the volume of the feed. Assume 300 days per year and 12 hours operation/day. The volume of the reactor in liters is
257.00 275.00 300.00 527.00
136 A container holds 100 gal of salt solution containing 50 lb of dissolved salt. The bottom of the container is covered with a layer of rock salt. The bottom of the container is covered with a layer of rock salt whose surface is practically constant. The salt dissolved into the solution according to r = k(C-3) where C is the concentration of the brine expressed in lb/gal. If the water in the tank were fresh, the rate of solution would be 1.0 lb/min. Fresh water enters at 3 gpm and brine overflows at the same rate. Assume constant volume at any brine concentration, the concentration of brine in container after 1 hour in lb/gal of salt is
0.73 0.43 0.33 0.24
137 An aqueous solution of ethyl acetate is to be saponified with NaOH. The initial concentration of the ethyl acetate is 5 g/L and that of the caustic soda is 0.10M. Values of the second order rate constant in L/gmole-min are k = 23.5 at 0 degC; k = 92.4 at 20 degC. The reaction is essentially irreversible. The time required to saponify 95% of the water at 40 deg C is
10.30 11.40 12.70 20.70
138 At 500K the rate of bimolecular reaction is 10 times the rate at 400K. Find E in cal, the activation energy for this reaction from Arrhenius Law.
8150.00 9150.00 9550.00 10150.00
139 The reaction A+2B--->R is 1st order with respect to each reactant. If equimolar amounts of A and B are introduced into a constant-volume reactor and (1/m) th of A remains after t1, how much will remain after t2=2t1?
Cao/2m Cao/(2m-1) Cao/(1-2m) Cao/2
140 When the 1st order homogeneous reaction (gas-phase) A--->2.5R is carried out in an isothermal batch reactor at 2 atm with 20% inerts present, the volume increases by 60% in 20 min. When the reaction is carried out in a constant volume reactor, the time required for the pressure to reach 8 atm if the initial pressure is 5 atm, 2 atm of which consist of inerts in min is
43.10 41.30 37.10 31.80
141 When the ID of the pipe through which a fluid flows is doubled, the pressure loss due to friction per unit length of pipe and for the same volumetric flow rate is changed by approximately a factor of
1/8 1/16 1/32 1/64
142 When two centrifugal pumps are connected in series, the discharge changes by a factor of
1/2 1.00 2.00 4.00
143 When two reciprocating pumps are connected in parallel, the volumetric capacity of the system changes by a factor of
1/2 1.00 2.00 4.00
144 The pressure drop in a pipeline changes by a factor of _____ when the velocity of the flowing fluid is doubled.
1/2 1.00 2.00 4.00
145 Cavitation occurs in a centrifugal pump when the discharge pressure becomes too high
the discharge valve is closed
the suction pressure is too high
suction is lost
146 Oil with a viscosity of 30 cP and a density of 60 lb/cu.ft. flows through a 1/2-inch inside diameter pipe. Determine the velocity in fps below which flow will be laminar.
0.63 13.10 16.90 87.20
CHEMICAL ENGINEERING REVIEW QUESTIONS 10
147 Water at 60 deg F flows through a 3-inch inside diameter smooth horizontal pipe. If the Reynold's number is 353000, calculate the ratio of maximum velocity to average velocity.
1.05 1.22 1.72 1.89
148 The pressure after the pump in a 6-inch inside diameter smooth pipe conducting water is 20 psia. The water is discharged at an open tank 100 ft from the pump. Calculate the rate of discharge of water in cu.ft/s.
0.60 3.58 21.00 58.30
149 A water storage tank assumes the supply of water into a factory. Water is supplied to the tank through a booster pump installed in the water line. The theoretical pump horsepower required is 3.25 hp. What is the monthly operating cost of the pump if electric power cost on the average is PhP 3.73/kWh. The pump is 65% efficient and operates for 12 hr a day.
PhP 3300 PhP 5000 PhP 7000 PhP 12000
150 When the impeller speed of an ideal centrifugal pump is doubled, the vol. flow rate of discharge is increased by a factor of
1/2 1.00 2.00 2exp2
151 The differential height between two points which a fluid has to be transferred is the
potential head pressure head velocity head dynamic head
152 The resistance of a layer of fluid to flow over the next layer is measured by
viscosity friction factor surface tension drag coefficient
153 An axial flow pump operating at a speed of 880 rpm can supply water at a rate of 3000 gpm. The maximum head that this pump can deliver in ft. of water is
20.00 36.00 63.00 85.00
154 Specify the type of open impeller pump to use if the capacity is 400 gpm at a head of 200 ft of water.
3x2x8.5E 4x3x8.5E 4x3x6 3x2x13
155 What will be the rated capacity [gpm] of a 4-1/2 inch impeller centrifugal pump operating at a speed of 3450 rpm capable of generating a head of 40 ft of water.
95.00 134.00 248.00 320.00
156 If the speed of a centrifugal pump is doubled, the energy requirement becomes approximately ___ times the original energy requirement.
2.00 4.00 8.00 10.00
157 A cylindrical tank 1 ft in diameter discharges through a nozzle connected to the base. Find the time needed for the water level in the tank to drop from 4 ft to 2 ft above the nozzle. The diameter of the nozzle is 1 inch and its discharge coefficient maybe taken as unity.
32.00 55.00 77.00 94.00
158 The NPSH of a single suction centrifugal hot water pump at a speed of 3550 rpm operating at a pressure of 600 psi and a capacity of 450 gpm is ___ ft.
15.00 20.00 25.00 30.00
159 The rate of evaporation at a given operating temperature in a n evaporator is more when
when the operating pressure is high
the operating pressure is low
there is a vacuum when the liquid level is high
160 An optimim number of the effects for a given application is a function of the
capacity economy efficiency none of the given choices
161 A popular type of heat exchanger for cooling large quantities of fluid is the
double-pipe plate shell and tube extended surfaces
162 An evaporator is used to concentrate 10,000 lb/hr of a 20% solution of NaOH in water at 140oF using saturated steam at 25 psia at a rate of 7,000 lb/hr. The OHTC is 275 BTU/hr-ft2-oF when the pressure in the vapor is 1.7 psia. The steam economy, SE, is
0.82 0.86 0.89 0.92
163 A cross flow heat exchanger uses mixed air at 4 kg/s that enters at 15oC and leaves at 45oC. The air cools unmixed water, which enters at 95oC and 0.70 kg/s. The OHTC equals 150 W/m2-oC. After several months of operation, a scale resistance of 0.002 m2-oC/W developed. 16. The heat transfer area required to accomplish the change is
22.2 m2 25 m2 17 m2 20 m2
164 As solution of 28% wt Na2SO4 is to be crystallized 285.30 249.30 255.65 214.65
CHEMICAL ENGINEERING REVIEW QUESTIONS 11
to yield Glauber salt in a four section (one section is 10 ft in length) Swenson Walker Crystallizer. It is fed to the unit at 120oF and cooled to 60oF using cooling water which enters at 50oF and leaves at 70oF. The crystallizer has a cooling surface of 3 ft2 per foot of length. The feed rate is 500 lb/hr and the crystallizer is seeded with 50 lb/hr of 65 mesh crystals. 19. The amount of the crystalline crop (C) produced in lb per hour is
165 An insulator should have low thermal conductivity
high thermal conductivity
less resistance to heat flow
a porous structure
166 Fouling factor is a dimensionless quantity
does not provide a safety factor for design
accounts for additional resistance to heat flow
none of these
167 Natural convection is characterized by Reynolds number Grashhoff number Peclet number Prandlt number168 The Graetz number is concerned with mass transfer
between a gas and a liquid
absorption with chemical reaction
heat transfer in turbulent flow
heat transfer in laminar flow
169 Dropwise condensation occurs on clean and dirt free surfaces
smooth clean surfaces contaminated cooling surfaces
polished surfaces
170 Dietus-Boelter equation for determination of heat transfer co-efficient is valid
for liquid metals for fluid in laminar flow for fluids in turbulent flow
when Grashhoff number is very important
171 A type of pneumatic conveyor system characterized by a material moving in an air stream or pressure less than ambient.
fluidizing pressure pressure-vacuum vacuum
172 If the total percentage of particles larger than the screen opening in the feed, oversize, undersize are 36%, 89% and 3%, respectively, the effectiveness of the screen if the undersize is the product is
0.98 0.89 0.76 0.65
173 The estimated width of an apron conveyor having a capacity of 75 tons/hr at a speed of 50 ft/min is
305 mm 610 mm 1220 mm 2400 mm
174 It is defined as the ratio of the average diameter of the feed to the average diameter of the product.
settling ratio screen-mesh no reduction ratio average particle diameter
175 The sphericity of cubical particles is 1.00 0.87 0.70 0.60176 The separation of a dilute slurry or suspension by
gravity settling into a clear fluid and a slurry or suspension by gravity settling into a clear fluid and a slurry of higher solids content is called
thickening classification sorting centrifugation
177 An ultracentrifuge is used to separate high-molecular weight fractions in polymeric or biological systems. What is the gradient for mass transfer in the separation using this mass transfer device?
temperature pressure concentration electric field
178 Ordinary diffusion takes place because of ___ driving force.
temperature pressure concentration electric field
179 What are the two limiting cases of steady-state diffusion?
UMD and EMD ordinary and Knudsen thermal and ordinary thermal and Knudsen
180 Which of the following is not true in (binary) equimolar counter-diffusion?
DAB = DBA c = cA + cB JA = JB NA = -cDAB dxA/dz
181 A fluid is flowing on a surface, which contains a component that leaches out to the fluid. Assuming that all the 3 regions of mass transfer are present, in which of these regions is diffusion controlling?
Knudsen region turbulent region buffer region viscous sub-layer
182 In unsteady-state mass transfer, the quantity (DABt/rm^
2) is referred to asunaccomplished change
relative resistance relative time relative position
183 What is the equivalent of Prandtl number in convective mass transfer?
Sc Sh Bi Pe
184 If kx > ky, then the controlling phase is the liquid phase the gas phase the interface either of the bulk phases
185 In two-phase mass transfer, equilibrium may exist at the interface in the gas phase in the liquid phase in either film186 Which of the following processes may always be
regarded as a constant- humidity process?cooling of air air conditioning water-cooling in a
cooling towerheating of air
CHEMICAL ENGINEERING REVIEW QUESTIONS 12
187 Air conditioning in tropical countries involves humidification by a process similar to that in a cooling tower
humidification by a process similar to air-water vapor saturator
dehumidification and removal of sensible heat
dehumidification by condensing water vapor in a refrigerator
188 What do you call the steady-state non-equilibrium temperature reached when a small amount of water is contacted under adiabatic conditions by a continuous stream of gas?
dry-bulb temperature
wet-bulb temperature adiabatic saturation temperature
dew point temperature
189 The moisture content of a solid is given as 50% wet basis. What is the moisture content, dry basis?
0.50 1.00 2.00 50.00
190 The moisture that can be removed by drying is called
equilibrium moisture
bound moisture free moisture unbound moisture
191 Falling-period in drying terminates at the end of constant-rate period
origin of R vs X plot critical free moisture content
equilibrium moisture content
192 Which is not true at the interphase of a gas scrubbing operation?
the solute concentration of the gas is less than that of the bulk
the solute concentration of the liquid is less than that of the bulk
the solute concentration of the liquid and gas phase are equal
the solute concentration of the gas is greater than the liquid
193 He and N2 gas are contained in a conduit 5 mm in diameter and a 0.1 m long at 298 K and a uniform pressure of He at one end of the tube is 0.6 atm and 0.02 atm at the other end. Assuming equimolar countercurrent diffusion, the flux in kmol/s-m2 is
2.35 exp -5 2.44exp -5 1.77exp -6 1.22 exp -6
194 100 m3/hr of air at 60°C and 20% RH is needed for a chemical reactor. This will be obtained from process air at 60°C and 10% RH by humidifying adiabatically the process air followed by heating to its original temperature. The wattage of the heater at 80% efficiency is
5280.00 8490.00 10050.00 11570.00
195 Wet solid is to be dried from 36% to 8% moisture in 5 hr under constant drying condition. Critical and equilibrium moisture contents are 14 and 4% respectively. Calculate how much longer will it take to dry the same material from 8% to 5.5% moisture under constant drying condition. All moisture contents are on a dry basis.
1 hr 1.6 hr 2.3 hr 2.9 hr
196 The unit of volumetric diffusivity is cm^2/sec cm/sec cm^3/sec cm^2/sec^2
197 If reflux to a distillation column is 100 moles/hr, when the overhead product rate is 50 moles/hr. the reflux ratio is
0.50 2.00 50.00 150.00
198 Which of the following provides maximum contact surface for a liquid-vapour system?
packed lower bubble-cup plate column
sieve-plate column wetted wall column
199 In extraction, as the temperature increases, the area of heterogeneity (area covered by bimodal curve)
decreases increases remains unchanged
200 The suitable evaporator for concentration of foaming liquids is
long tube evaporator
short tube evaporator vacuum evaporator falling film evaporator
201 Macroscopic transfer of mass between moving fluid and surface which is of different concentration is called
molecular diffusion unsteady-state diffusion
convective mass transfer
all of these
202 For a packed column the main purpose of packing is to
strengthen the column
increase the surface area
increase the pressure drop in the tower
reduce the flow rate across the column
203 In a gas absorption operation, when the operating line crosses the equilibrium curve
the NTU is zero the liquid flow rate is maximum
the gas flow rate is maximum
the number of stages is infinite
204 Methanol diffuses in 0.15 cm stagnant film of 1:1 mole mixture of hydrogen and CO2 at 100oC and 2 atm. The partial pressures of methanol on both sides are 0.6 and 0.2 atm. The average diffusivity of methanol in the hydrogen and CO2 at 0 oC and 1 atm in cm2/s is
0.15 0.31 0.51 0.68
205 Gaseous reactant A decomposes according to the reaction A --> 3R (-rA = 0.5 CA mole/L-min). The feed, which consists of 70% A and 30% inert,
0.92 0.86 0.71 0.65
CHEMICAL ENGINEERING REVIEW QUESTIONS 13
enters a 1.5-m3 CSTR at a flow rate of 150 L/min. 4. If CA0 = 0.30 mole/L, what is the conversion, XA?
206 Between 0 degC and 50 degC, the average activation energy of a certain reaction is 80 kJ/mol. How many times faster will the reaction occur at 300 K than at 275 K?
14.70 18.50 20.90 22.40
207 Consider a gas-phase reaction 2A ---> R + 2S with unknown kinetics. A space velocity of 0.8/min is needed for 95% conversion of A in a PFR. Find the mean residence time or holding time of the fluid in the PFR.
0.54 min 0.85 min 0.87 min 1.18 min
208 For Newtonian fluids, the shear stress is constant. inversely proportional to rate of deformation.
equal to shear rate of deformation.
a linear function of the shear rate of deformation.
209 An ideal fluid is one that is compressible incompressible & viscous
incompressible incompressible & inviscid
210 Water flows through an 8-in (ID=7.981 in) steel pipe at an average velocity of 6 ft/s. Downstream the pipe splits into an 8-in main and a 2 in (ID=2.067 in) bypass pipes. If the velocity in the bypass is twice the velocity of the main pipe, the volumetric flow rate [ft3/s] in the main pipe is
10.58 5.29 1.84 0.25
211 An imaginary line within a fluid flow such that a tangent at any point indicates the direction of flow at that point.
stream tube velocity profile streamline none of these
212 Air at 250C [viscosity=0.018 cP] enters a section of 2-in schedule 40 commercial steel pipe at a gauge pressure of 310 kPa and a flow rate of 1200 kg/h. Assuming isothermal flow, what is the pressure drop [kPa] in 60 m of pipe?
350.00 155.00 101.30 61.00
213 A simple pitot tube measures acoustical velocity superficial velocity mean linear velocity local velocity
214 Which of the following meters will have the highest permanent pressure loss?
pitot tube orifice venturi rotameter
215 In the flow meter equation, Y, indicates the mass flow rate compressibility factor coefficient of discharge cross-sectional area
216 The loss due to sudden contraction is proportional to
velocity turbulence velocity head static head
217 Stoke’s law is valid when the particle Reynolds number is
< 1 > 1 < 5 0.00
218 Priming needed in a Reciprocating pump
Gear pump Centrifugal pump Diaphragm pump
219 Maximum theoretical suction lift for water at 60˚F by a centrifugal pump is 34 ft. The same for water at 200˚F will be
40 ft 37 ft 34 ft 8 ft
220 The most economical valve for use with large diameter pipes.
butterfly globe needle gate
221 Multistage compressors are used in industry because, they
reduce the cost of compressor
reduce the size requirement
resemble closely to isothermal compression
are easy to control
222 For ideally incompressible fluid, the mach number will be
0.00 1.00 1.50 5.00
223 of the following produces maximum pressure difference for transportation of gases?
vacuum pumps blowers fans compressors
224 The fluid property which matters for falling rain drops to acquire spherical shape is its
pressure height of descend viscosity surface tension
225 A wastewater solution having a volume of 1000 L contains 0.21 kg phenol/m3 of solution. A total of 1.40 kg fresh granular activated carbon is added to the solution, which is then mixed thoroughly to reach equilibrium. What is the amount of phenol absorbed per kg carbon at equilibrium?
0.007 kg 0.106 kg 0.189 kg 0.198 kg
226 The overhead product composition decreases with time in
batch distillation with reflux
continuous distillation with reflux
continuous distillation without reflux
distillation operating at total reflux
CHEMICAL ENGINEERING REVIEW QUESTIONS 14
227 For a binary mixture with low relativity, continuous rectification to get pure products will require
low reflux ratio small cross-section less number of trays high reflux ratio
228 Chemisorption is the same as van der Waals
characterized by adsorption of heat
an irreversible phenomenon
always in equilibrium
229 The stage efficiency in leaching depends on the time of contact between the solid and the solution
rate of diffusion of the solute through the solid and into the liquid
both A and B either A or B because these two mean the same thing
230 Weeping in distillation or absorption column increases tray efficiency
provides larger surface for mass transfer
results due to low gas velocity
is due to bubble cups
231 What are the two contacting phase in leaching? extract phase and raffinate phase
solvent phase and solute phase
feed phase and solvent phase
overflow and underflow
232 Hydrogen sulfide is removed from water by contacting the solution with warm air. The operation is
Distillation Leaching Absorption Stripping
233 Disregarding the cost, which is the best solvent for the extraction of acetic acid from an aqueous solution at 25deg C?
caproic acid chloroform 3-heptanol toluene
234 Professional Regulations Commission was created under
P.D. No. 223 P.D. No. 233 P.D. No. 232 P.D. No. 826
235 A chemical engineer who designed and built a new type pf reactor and for three years, sold many units to the public can still patent his reactor.
TRUE FALSE it depends not governed by law
236 A person who has passed the Chemical Licensure Examination can take his/her oath as a chemical engineer if his/her age is not less than _______ years.
18.00 19.00 21.00 23.00
237 Which of the following is not a requirement for utility model registration?
inventive step novelty industrial applicability a technical solution to problem
238 A section of the patent application containing detailed descriptions of the benefits obtained from using the invention is called the
disclosure abstract request claims
239 A document issued by the DENR secretary indicating that the proposed project will cause significant negative environmental impact.
Environmental Impact Statement
Environmental Compliance Certificate
Environmental Impact Assessment
Environmental Critical Project
240 In the Philippines, sulfur for sulfuric acid manufacturing is sourced from _______ industry.
paper cement petroleum detergents
241 Sulfur is undesirable in petroleum because it causes engine knocking
it increases the boiling pt of fuel
it poisons the catalyst in the refining process
all that are mentioned
242 Materials added to detergent formulation to enhance cleaning performance by exhibiting synergistic cleaning effect with surfactant.
fillers brighteners builders perfume
243 Polyethylene is an example of _____________ polymerization
condensation addition copolymerization natural
244 Principal chemical conversion in the production of resin from monomer.
condensation hydration polymerization alkylation
245 Carbon black is added to rubber compounding as activator curing agent retarders fillers246 The binder for all the powder materials of paint pigment vehicle opacifier filler247 A fibrous material left after cane sugar has been
milled is commonly called asbagasse pulp cellulose waste
248 Molasses is a by product of raw sugar from the ______ process
milling extraction evaporation crystallization
249 Kraft process is a common name for sulfate pulping sulfite pulping bleaching calendering250 Water insoluble cell binders of wood pulp cellulose xylem lignin251 DDT means Diphenyldichlorotrip
henylethanedichlorodiphenyldichloroethane
Dichlorodiphenyldichlorobutane
diphenyldichlorotriphenylbutane
252 Rancidity of oil can be reduced by decoloration hydrogenation oxidation purification253 Varnish does not contain pigment dryer thinner anti-skinning agent
CHEMICAL ENGINEERING REVIEW QUESTIONS 15
254 Plasticizers are added to paints to make it corrosion resistant
make glossy surface increase atmospheric oxidation
give elasticity and prevent cracking of the film
255 Silicone is thermoplastic a monomer an inorganic polymer thermosetting plastic
256 The process involved in converting rubber into a thin sheet or coating it on fabric is called
extrusion mastication vulcanization calendering
257 Alkyl benzene sulfonate (ABS) is a detergent rubber pesticide polyester258 Neoprene is a monomer synthetic rubber polyester pigment259 Steam enters an adiabatic turbine at 10 MPa and
500 degC at a rate of 3 kg/s and leaves at 0.1 MPa. If the power output of the turbine is 2 MW, determine the turbine efficiency.
0.23 0.32 0.68 0.77
260 Work is a property of the system
path function state function state description of a system
261 Throttling process is a reversible and isothermal process
an irreversible and constant entropy
a reversible and constant entropy process
constant enthalpy process
262 A sample consisting of 1.00 mole of Argon gas is expanded isothermally and reversibly at 0°C from 22.4L to 44.8L. The heat absorbed by the system is
0.00 +1.13 kJ +1.57 kJ +2.27 kJ
263 Maximum work can be obtained from a system when the change taking place in it is
isothermal adiabatic reversible irreversible
264 The ratio of work performed by a system and the heat it absorbed from a reservoir is referred to
Entropy Gibb’s free energy carnot efficiency Helmholtz free energy
265 According to the first law of thermodynamics Energy is neither lost nor gained in any energy transformation.
Perpetual motion is possible.
Energy is conserved in quality but not in quantity.
Energy is being created as time passes. We have more energy in the universe now than when time began.
266 In a 3-stage compressor system whose isentropic efficiencies are reported to be 0.75, 0.85 and 0.84, respectively, steam initially at 10 kPa is compressed to a final pressure of 500 kPa. The overall efficiency of the system is
greater than 0.85 in between 0.75 and 0.85
less than 0.75 in between 0.84 and 0.90
267 In choosing the refrigerant, the fluid must have the following characteristics, except
environmentally benign
has a vapor pressure less than atmospheric
must be economically viable
exist at a high pressure at the condensation temperature
268 Coolers and boilers are ordinarily operated at ________ condition.
isobaric isenthalpic isothermal isentropic
269 For an isolated system, maximum entropy will occur at
half-life critical condition equilibrium start of the process
270 A carnot cycle consists of two isothermal and two adiabatic process
two isochoric and two adiabatic process
one isochoric, one isobaric, and two adiabatic process
one isothermal, one isochoric and two adiabatic process
271 This is also known as the volume fraction of the voids in packed beds.
sphericity porosity superficial velocity specific volume
272 A measure of the ratio of the drag force acting on a unit area of the impeller & the inertial stress.
Froude number Reynold’s number Mach number Power number
273 Sulfuric acid is pumped at 3 kg/s through a 60-m length of smooth 25 mm pipe. If the pressure drop falls by one-half, what will be the new flow rate [kg/s]? Assume the following properties of sulfuric acid: SG = 1.84, viscosity = 25 cP.
3.00 2.00 0.20 0.12
274 The equation del(P) = -(rho)(g) del(z) is known as the hydrostatic vertical law for which all the following assumptions are applied, except
shear forces are not involved
fluid is incompressible z axis is defined vertical & downward in direction
normal surface forces & gravity are the only forces involved
275 Which of the following can be adjusted by human operator in a closed feedback control loop?
set point controller output process variable load variable
276 The thermocouple is based on the Seebeck effect current temperature emf resistance
CHEMICAL ENGINEERING REVIEW QUESTIONS 16
which states that a/an _____ is generated when opposite junction of certain dissimilar pairs of wires are exposed to different temperatures.
277 Dead time is a function of distance and momentum acceleration time velocity278 A pneumatic controller is used to control
temperature within the range 280K to 310K. The controller is adjusted so that the output pressure goes from 20kPa (valve fully open) to 105 Kpa (valve fully closed) as the measured temperature goes from 295K to 300K with the sent point held constant. What is the proportional gain?
2.83kPa/K 0.35kPa/K 17kPa/K 0.06kPa/K
279 The parameter which completely describes the behavior of the response to a disturbance of a second order system is the
Time constant damping coefficient Rise time overshoot
280 Water is flowing through a 3-inch schedule 40 pipe at 60 deg F. A pitot tube is inserted at the centerline of the pipe and registers a 3-inch Hg differential. What is the mass flow rate of the water?
11.61 ft/s 37.1 kg/s 37.1 lb/s 317 lb/s
281 An oil well is 1200 ft below ground level. Oil at 500 psig at the bottom flows to ground level through a 12-inch schedule 80 commercial steel pipe. The oil has a SG of 0.86 and viscosity of 8 cP. The vol flow rate of oil in barrels per hour is
9365.00 9461.00 52581.00 393308.00
282 The equivalent diameter of a concentric annular space where 1-inch OD pipe is located inside a 2-inch ID pipe is
pi/4 inch 1 inch 1.5 inch 2 inches
283 Based on Bond's crushing law, the power required to crush a certain material will change by _____% if the diameter of the product is made smaller by 50%.
20.20 41.40 50.50 58.60
284 The BPR of a 50% NaOH solution at an evaporator pressure of 4.7 psia is
73 degF 173 degF 233 degF 297 degF
CHEMICAL ENGINEERING REVIEW QUESTIONS 17
ANSWERS
1A
51C
101A
151A
201 C
251 C
2C
52A
102B
152A
202 B
252 B
3D
53B
103A
153B
203 D
253 A
4D
54B
104B
154A
204 C
254 D
5B
55A
105C
155C
205 C
255 C
6C
56C
106a
156C
206 B
256 D
7C
57C
107C
157C
207 B
257 A
8C
58B
108A
158B
208 D
258 B
9D
59C
109C
159B
209 D
259 C
10C
60D
110A
160B
210 C
260 B
11D
61C
111B
161C
211 C
261 D
12C
62D
112C
162B
212 D
262 C
13C
63B
113A
163D
213 D
263 C
14C
64A
114B
164B
214 B
264 C
15C
65A
115B
165A
215 B
265 A
16A
66C
116A
166C
216 C
266 B
17B
67A
117C
167B
217 A
267 D
18B
68C
118C
168D
218 C
268 A
19D
69D
119D
169C
219 B
269 C
20B
70A
120C
170C
220 A
270 A
21C
71B
121D
171D
221 C
271 B
22D
72A
122C
172B
222 B
272 D
23B
73B
123A
173C
223 D
273 B
24D
74D
124A
174C
224 D
274 C
25D
75C
125B
175A
225 B
275 A
26C
76B
126B
176A
226 A
276 C
27B
77C
127C
177B
227 D
277 D
28B
78A
128D
178B
228 C
278 C
29B
79B
129D
179A
229 C
279 B
30C
80A
130C
180C
230 C
280 C
31C
81D
131B
181D
231 D
281 A
32B
82C
132C
182C
232 D
282 B
33B
83C
133C
183A
233 C
283 B
CHEMICAL ENGINEERING REVIEW QUESTIONS 18
34A
84D
134A
184B
234 A
284 A
35C
85A
135A
185A
235 A
36B
86D
136C
186D
236 C
37B
87B
137A
187C
237 A
38C
88A
138B
188B
238 D
39B
89C
139B
189B
239 B
40A
90B
140D
190C
240 A
41A
91D
141C
191D
241 A
42A
92A
142C
192A
242 C
43B
93C
143B
193A
243 B
44B
94C
144D
194D
244 D
45C
95A
145C
195B
245 A
46C
96D
146C
196C
246 A
47A
97D
147B
197B
247 C
48D
98B
148B
198A
248 C
49B
99B
149B
199A
249 B
50C
100B
150C
200A
250 D
CHEMICAL ENGINEERING REVIEW QUESTIONS 19