NO QUESTION A B

1 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
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
0.052 0.025
3 The equation that relates friction factor and Reynold's No.,
f=64/Reynold's No. holds for
smooth pipes laminar and
turbulent flow
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
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.
6 The enrichment of the vapor steam as it passes through the
column in contact with the reflux during distillation is called
evaporation stripping
7 The maximum number of plates for a given distillation system is
obtained at
variable reflux maximum 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
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
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
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
12 Crystallization occurs in a solution that is concentrated unsaturated
13 Mass transfer in a flowing fluid may be correlated by Sherwood,
Nusselt and
Reynold's No
Peclet,
Reynold's and
Schimdt No
14 The ratio of the average diameter of the feed to the average
diameter of the product is the
settling ratio discharge 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
16 A device for increasing the velocity of a fluid in steady flow is a nozzle vent
17 In steady-state backmix flow reactor, composition is not constant
throughout the
reactor
constant
throughout the
reactor
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
19 In fractionation, an increase in reflux ratio increases the
number of
theoretical
plates
decreases the
reboiler duty
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
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
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
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
24 Which one of the following pipes has the highest relative
roughness?
2" diameter
Wrought iron
pipe
4" dia Wrought
iron 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
26 Reactions whereby reactants proceed along several paths and
give different products are
polymeric
reactions
reversible
reactions
27 Which one among the following materials has the best insulating
property?
window glass wood
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
29 The pressure exerted on a plane parallel to the direction of flow
of a moving fluid is called
gauge pressure velocity pressure
30 For mass transfer to take place, there must be a phase change reaction
component
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
32 The diffusity of water in air at 100 deg F in sq.cm./sec is 0.256 0.278
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
5.9 2.5
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
66.6 58.1
35 When 32 kg of methane is burned completely the theoretical
oxygen required is
16 kg 64 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
32.2 31.4
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 2.18
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
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
0.0378 0.0504
40 A metallic rod 2 cm in diameter is used as a heating element.
The thermal conductivity is 370 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
4440000 5130000
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
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
74.3 75
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
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
0.1 0.05
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
46 This type of drier is used for drying pasty materials such as wet
filter cakes and lumpy solids
rotary drier flash 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
48 Unbound moisture in granular and porous solid moves through
the intertices of the solid by a mechanism involving
desorption surface tension
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
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 0.034
51 In drying at the falling rate period, the rate at which moisture is
removed from the solid material
remains
constant
increases with
time
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
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
0.3 0.8
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 mulitple 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 conposed of 15% oil. The theoretical number of
ideal stages is
3 4
55 The movement of molecules over a substantial distance is
associated with the transfer of heat by
convection conduction
56 The mode of heat transfer that can take place in a vacuum is
known as
convection conduction
57 The overall conductance for a composite material in series is
equal to the
sum of the
individual
conductances
sum of the
individual
conductivities
58 Film and drop are terms associated with boiling condensation
59 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.
99.95 415.7
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.
97 242
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
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
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 evpaorator 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.
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
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
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?
10.92 9.12
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 38
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 9
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?
72.2 28.7
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?
0.492 0.429
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 h
of 1000 Btu/hr-sq.ft.-degF, calculate the inside heat transfer
coefficient [Btu/hr-cu.ft-degF].
2173 696
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
72 Nicotine is to be extracted from water using kerosene. If 100 lb of
a 2% nicotene solution is extracted once with 200 lb of kerosene,
what percent of the nicotene is extracted? {Equilibrium data: Y[lb
nicotene/lb kerosene] = 0.90X [lb nicotene/lb water]}
64.5 54.6
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.
77.2 150
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 8457
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 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]?
10500 35000
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.
38.1 18.3
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 1644
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
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 84
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]
34.2 27.7
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
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?
113 227
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 0.5
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 )
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.
75.2 55.2
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 the cylinder [W
per meter length].
13 272
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].
0.028 0.119
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].
325 300
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
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 18
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].
170 100
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
93 If the absolute temperature of a gas is doubled, the mean speed
of the gas molecules
is doubled. increases 4
times
94 When ice cubes melt in a glass of water, the temperature of the
resulting mixture of water and ice
increases. decreases.
95 In all naturally occurring processes, the entropy of the universe increases. decreases.
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
Thermodynami
cs.
The application
should be
rejected
because it
violates the
second law of
Thermodynamic
s.
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.
98 A 30 MW geothermal electric power plant uses hot 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 degC 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?
2.5 e8 2.2 e8
99 The material which remains unchanged in a process is limiting reactant tie substance
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
101 The heating value measured when water formed from
combustion is in the liquid state.
Gross Calorific
Value
Heat of
combustion
102 In the combustion of solid fuels, the tie element between the feed
and the refuse is the
cooked coal ash
103 The coal analysis which is based upon the volatilization
characteristics of the fuel is
Proximate
analysis
Modified
analysis
104 An Orsat analysis of the flue gas when pyrite is roasted is on a SO2-free basis SO3-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
106 The equivalent of 45degTw in the Baume scale is 26.63 28.32
107 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?
1.2 1.53
108 Which has the lowest water content? dew point at
20degC
70% RH
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? Freiht cost is PhP45/tonne.
PhP 405 PhP 424.26
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
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 3750
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
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
0.8 0.85
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 % methane in
the fuel gas is
63.25 57.24
115 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
116 The unit of k for a 1st order elementary reaction is 1/time conc/time
117 If the temperature of a chemical reaction is raised by 10 degC,
the rate of reaction is increased by a factor of
4 3
118 The E of a reaction may be lowered by increasing
temperature
decreasing
temperature
119 The mechanism of a reaction can sometimes be deduced from the activation
energy
the temperature
dependency of
the rate
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
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 4
122 The rate of reaction is not influenced by conc of the
reactants
molecularity of
the reaction
123 The net rate of reaction of an intermediate is 0 2
124 A reaction is known to be first order in A. A straight line will be
obtained by plotting
log Ca vs time 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
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
127 It states that the rate of a chemical reaction is proportional to the
activity of the reactants.
Le Chatelier's
principle
Hess' Law
128 The half life of a material undergoing second order decay is proportional to
the square of
the initial conc
independent of
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.
66.8 74.7
130 A first order reaction has a specific rate constant of 3e-3 per sec.
The half life is
0.0021 s 100 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
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
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
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 value of K2 per hour is
0.1697 0.183
135 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
257 275
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
0.732 0.427
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
10.3 11.4
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 9150
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)
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
43.1 41.3
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
142 When two centrifugal pumps are connected in series, the
discharge changes by a factor of
1/2 1
143 When two reciprocating pumps are connected in parallel, the
volumetric capacity of the system changes by a factor of
1/2 1
144 The pressure drop in a pipeline changes by a factor of _____
when the velocity of the flowing fluid is doubled.
1/2 1
145 Cavitation occurs in a centrifugal pump when the discharge
pressure
becomes too
high
the discharge
valve is closed
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 13.1
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
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.
0.6 3.58
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
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
151 The differential height between two points which a fluid has to be
transferred is the
potential head pressure head
152 The resistance of a layer of fluid to flow over the next layer is
measured by
viscosity friction factor
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 36
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
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.
95 134
156 If the speed of a centrifugal pump is doubled, the energy
requirement becomes approximately ___ times the original
energy requirement.
2 4
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 55
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 20
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
160 An optimim number of the effects for a given application is a
function of the
capacity economy
161 A popular type of heat exchanger for cooling large quantities of
fluid is the
double-pipe plate
162 An evaporator is used to concentrate 10,000 lb/hr of a 20%
solution of NaOH in water at 140
o
F using saturated steam at 25
psia at a rate of 7,000 lb/hr. The OHTC is 275 BTU/hr-ft
2
-
o
F
when the pressure in the vapor is 1.7 psia. The steam economy,
SE, is
0.82 0.863
163 A cross flow heat exchanger uses mixed air at 4 kg/s that enters
at 15
o
C and leaves at 45
o
C. The air cools unmixed water, which
enters at 95
o
C and 0.70 kg/s. The OHTC equals 150 W/m
2
-
o
C.
After several months of operation, a scale resistance of 0.002 m
2
-
o
C/W developed. 16. The heat transfer area required to
accomplish the change is
22.2 m
2
25 m
2
164 As solution of 28% wt Na
2
SO
4
is to be crystallized 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 120
o
F and
cooled to 60
o
F using cooling water which enters at 50
o
F and
leaves at 70
o
F. The crystallizer has a cooling surface of 3 ft
2
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
285.3 249.3
165 An insulator should have low thermal
conductivity
high thermal
conductivity
166 Fouling factor is a
dimensionless
quantity
does not provide
a safety factor
for design
167 Natural convection is characterized by Reynolds
number
Grashhoff
number
168 The Graetz number is concerned with mass transfer
between a gas
and a liquid
absorption with
chemical
reaction
169 Dropwise condensation occurs on clean and dirt
free surfaces
smooth clean
surfaces
170 Dietus-Boelter equation for determination of heat transfer co-
efficient is valid
for liquid metals for fluid in
laminar flow
171 A type of pneumatic conveyor system characterized by a material
moving in an air stream or pressure less than ambient.
fluidizing pressure
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
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
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
175 The sphericity of cubical particles is 1 0.87
176 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
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
178 Ordinary diffusion takes place because of ___ driving force. temperature pressure
179 What are the two limiting cases of steady-state diffusion? UMD and EMD ordinary and
Knudsen
180 Which of the following is not true in (binary) equimolar counter-
diffusion?
D
AB
= D
BA
c = c
A
+ c
B
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
182
In unsteady-state mass transfer, the quantity (D
AB
t/r
m^
2
) is
referred to as
unaccomplishe
d change
relative
resistance
183 What is the equivalent of Prandtl number in convective mass
transfer?
Sc Sh
184 If k
x
> k
y
, then the controlling phase is the liquid phase the gas phase
185 In two-phase mass transfer, equilibrium may exist at the interface in the gas phase
186 Which of the following processes may always be regarded as a
constant- humidity process?
cooling of air air conditioning
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
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
189 The moisture content of a solid is given as 50% wet basis. What
is the moisture content, dry basis?
0.5 1
190 The moisture that can be removed by drying is called equilibrium
moisture
bound moisture
191 Falling-period in drying terminates at the end of constant-
rate period
origin of R vs X
plot
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
193 He and N
2
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-m
2
is
2.35 exp
-5
2.44exp
-5
194
100 m
3
/hr of air at 60C and 20% RH is needed for a chemical
reactor. This will be obtained from process air at 60C 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 8490
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
196 The unit of volumetric diffusivity is
cm^
2
/sec
cm/sec
197 If reflux to a distillation column is 100 moles/hr, when the
overhead product rate is 50 moles/hr. the reflux ratio is
0.5 2
198 Which of the following provides maximum contact surface for a
liquid-vapour system?
packed lower bubble-cup plate
column
199 In extraction, as the temperature increases, the area of
heterogeneity (area covered by bimodal curve)
decreases increases
200 The suitable evaporator for concentration of foaming liquids is long tube
evaporator
short tube
evaporator
201 Macroscopic transfer of mass between moving fluid and surface
which is of different concentration is called
molecular
diffusion
unsteady-state
diffusion
202 For a packed column the main purpose of packing is to strengthen the
column
increase the
surface area
203 In a gas absorption operation, when the operating line crosses
the equilibrium curve
the NTU is zero the liquid flow
rate is maximum
204 Methanol diffuses in 0.15 cm stagnant film of 1:1 mole mixture of
hydrogen and CO
2
at 100
o
C 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 CO
2
at 0
o
C and 1 atm
in cm
2
/s is
0.15 0.31
205 Gaseous reactant A decomposes according to the reaction A -->
3R (-r
A
= 0.5 C
A
mole/L-min). The feed, which consists of 70% A
and 30% inert, enters a 1.5-m
3
CSTR at a flow rate of 150 L/min.
4. If CA0 = 0.30 mole/L, what is the conversion, XA?
0.92 0.86
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?
14.7 18.5
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
208 For Newtonian fluids, the shear stress is constant. inversely
proportional to
rate of
deformation.
209 An ideal fluid is one that is compressible incompressible
& viscous
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 [ft
3
/s] in the main pipe is
10.58 5.29
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
212
Air at 25
0
C [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?
350 155
213 A simple pitot tube measures acoustical
velocity
superficial
velocity
214 Which of the following meters will have the highest permanent
pressure loss?
pitot tube orifice
215 In the flow meter equation, Y, indicates the mass flow rate compressibility
factor
216 The loss due to sudden contraction is proportional to velocity turbulence
217 Stokes law is valid when the particle Reynolds number is < 1 > 1
218 Priming needed in a Reciprocating
pump
Gear pump
219 Maximum theoretical suction lift for water at 60F by a centrifugal
pump is 34 ft. The same for water at 200F will be
40 ft 37 ft
220 The most economical valve for use with large diameter pipes. butterfly globe
221 Multistage compressors are used in industry because, they reduce the cost
of compressor
reduce the size
requirement
222 For ideally incompressible fluid, the mach number will be 0 1
223 of the following produces maximum pressure difference for
transportation of gases?
vacuum pumps blowers
224 The fluid property which matters for falling rain drops to acquire
spherical shape is its
pressure height of
descend
225 A wastewater solution having a volume of 1000 L contains 0.21
kg phenol/m
3
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
226 The overhead product composition decreases with time in batch distillation
with reflux
continuous
distillation with
reflux
227 For a binary mixture with low relativity, continuous rectification to
get pure products will require
low reflux ratio small cross-
section
228 Chemisorption is the same as
van der Waals
characterized by
adsorption of
heat
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
230 Weeping in distillation or absorption column increases tray
efficiency
provides larger
surface for mass
transfer
231 What are the two contacting phase in leaching? extract phase
and raffinate
phase
solvent phase
and solute
phase
232 Hydrogen sulfide is removed from water by contacting the
solution with warm air. The operation is
Distillation Leaching
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
234 Professional Regulations Commission was created under P.D. No. 223 P.D. No. 233
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
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 19
237 Which of the following is not a requirement for utility model
registration?
inventive step novelty
238 A section of the patent application containing detailed
descriptions of the benefits obtained from using the invention is
called the
disclosure abstract
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
240 In the Philippines, sulfur for sulfuric acid manufacturing is
sourced from _______ industry.
paper cement
241 Sulfur is undesirable in petroleum because it causes
engine
knocking
it increases the
boiling pt of fuel
242 Materials added to detergent formulation to enhance cleaning
performance by exhibiting synergistic cleaning effect with
surfactant.
fillers brighteners
243 Polyethylene is an example of _____________ polymerization condensation addition
244 Principal chemical conversion in the production of resin from
monomer.
condensation hydration
245 Carbon black is added to rubber compounding as activator curing agent
246 The binder for all the powder materials of paint pigment vehicle
247 A fibrous material left after cane sugar has been milled is
commonly called as
bagasse pulp
248 Molasses is a by product of raw sugar from the ______ process milling extraction
249 Kraft process is a common name for sulfate pulping sulfite pulping
250 Water insoluble cell binders of wood pulp cellulose
251 DDT means Diphenyldichlor
otriphenylethan
e
dichlorodiphenyl
dichloroethane
252 Rancidity of oil can be reduced by decoloration hydrogenation
253 Varnish does not contain pigment dryer
254 Plasticisers are added to paints to make it
corrosion
resistant
make glossy
surface
255 Silicone is thermoplastic a monomer
256 The process involved in converting rubber into a thin sheet or
coating it on fabric is called
extrusion mastication
257 Alkyl benzene sulfonate (ABS) is a detergent rubber
258 Neoprene is a monomer synthetic rubber
259
Steam enters an adiabatic turbine at 10 MPa and 500
deg
C 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.
0.2348 0.3216
260 Work is a property of the
system
path function
261 Throttling process is a reversible
and isothermal
process
an irreversible
and constant
entropy
262 A sample consisting of 1.00 mole of Argon gas is expanded
isothermally and reversibly at 0C from 22.4L to 44.8L. The heat
absorbed by the system is
0 +1.13 kJ
263 Maximum work can be obtained from a system when the change
taking place in it is
isothermal adiabatic
264 The ratio of work performed by a system and the heat it
absorbed from a reservoir is referred to
Entropy Gibbs free
energy
265 According to the first law of thermodynamics Energy is
neither lost nor
gained in any
energy
transformation.
Perpetual
motion is
possible.
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
267 In choosing the refrigerant, the fluid must have the following
characteristics, except
environmentally
benign
has a vapor
pressure less
than
atmospheric
268 Coolers and boilers are ordinarily operated at ________
condition.
isobaric isenthalpic
269 For an isolated system, maximum entropy will occur at half-life critical condition
270 A carnot cycle consists of two isothermal
and two
adiabatic
process
two isochoric
and two
adiabatic
process
271 This is also known as the volume fraction of the voids in packed
beds.
sphericity porosity
272 A measure of the ratio of the drag force acting on a unit area of
the impeller & the inertial stress.
Froude number Reynolds
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 2
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
275 Which of the following can be adjusted by human operator in a
closed feedback control loop?
set point controller output
276 The thermocouple is based on the Seebeck effect which states
that a/an _____ is generated when opposite junction of certain
dissimilar pairs of wires are exposed to different temperatures.
current temperature
277 Dead time is a function of distance and momentum acceleration
278 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
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
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
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 9461
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
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%.
20.2 41.4
284 The BPR of a 50% NaOH solution at an evaporator pressure of
4.7 psia is
73 degF 173 degF
C D ANSWER SCORE
globe valve orifice
a 1
0.03 0.038
0
turbulent flow
only
laminar flow
only
0
equal to the
heat transfer
coefficient
equivalent to
the resistance
offerred by the
pipe
equal to the
heat transfer
coefficient of
the steam d 1
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.
b 1
rectification fractionation
c 1
minimum reflux optimum reflux
c 1
mol/liter/min liter/mol/min
0
no effect significant
effect
0
the heat
transfer is
constant
the
temperature is
uniform
throughout the
cylinder
0
transition plate bubble plate
0
supersaturated saturated c 1
Sherwood,
Reynold's and
Schimdt No
Prandtl,
Schimdt and
Reynold's No
0
reduction ratio classification
ratio
c 1
the value of k is
independent of
the initial
concentrations
of A and B
the reaction
cannot proceed
0
orifice venturi
a 1
a function of
time
not uniform
throughout the
reactor and
varies from
time to time
0
book value market value
b 1
increases the
amount of
distillate
increases the
condenser duty
0
the gas phase
resistance is
negligible
the ratio of gas
phase
resistance to
liquid
resistance is
approximately
zero
0
Peclet, Stanton
and Prandtl Nos
Schimdt,
Peclet and
Friction Nos
0
45-degree
standard elbow
square-corner
elbow
0
compressor accumulator
b 1
1" dia Drawn
tubing
4" dia Riveted
steel pipe 0
through each
material is
inversely
proportional to
the thickness of
the material
is constant
throughout the
series of
materials
0
parallel
reactions
consecutive
reactions
c 1
air concret
b 1
humidification extraction
b 1
tangential
pressure
static pressure
b 1
concentration
gradient
momentum
gradient
c 1
113 deg F 146 deg F
c 1
1.484 0.581 b 1
1.5 0.6
0
33.4 54.4
0
128 kg 32 kg
c 1
26.4 57.8
0
1.5 2.75
0
over 20 million over 2 but less
than 3
0
0.0454 0.0252
0
6930000 2040000
0
saturation
temperature
dry-bulb
temperature 0
75.26 78.5
0
the temperature
of the air can
also be
maintained
constant
increase in the
humidity of the
air is
insignificant
0
0.02 0.01
0
equilibrium
moisture
content
critical
moisture
content
c 1
tray drier freeze drier
c 1
air flow
perpendicular to
the surface of
the solid
air flow parallel
to the solid
surface
0
surface renewal moisture
diffusivity
d 1
2.129 hrs 3.42 hrs
0
0.01155 0.00116
0
decreases with
time
no drying takes
place
0
to use cross
flow
evaporation
to use spray
percolators
0
1.5 2.3
0
5 6
0
radiation all of A, B and
C
a 1
radiation all of A, B and
C
c 1
inverse of the
total resistance
sum of the
individual
resistances
c 1
evaporation all of A, B and
C
b 1
451.7 475.1
0
5800 139200
0
5.51 m 4.14 m
0
966 kg 534 kg
0
85.8 sq.m. 88.5 sq.m.
0
14 kPa zero gauge
0
4.72 3.03
0
39 40
0
8 7
0
27.8 22.7
0
0.294 0.249
0
577 241
0
13.76 16.28
0
46.5 45.6
0
227.2 300
0
11994 20451
0
40130 45500
0
13.8 5
0
1163 19.4
0
4.67 2
0
95 100
0
7 0.52
0
31.7 37.1
0
851 900
0
0.75 1
0
[B]=0.4(1-
0.5x )/(1-x )
[B]=0.2
0
25.2 20
0
3478 3750
0
0.714 6.01
0
100 25
0
13943 W 19343 W
0
23 33
0
38 0.038
0
both contain the
same no of air
molecules
0
increases by
about 40%
decreases.
c 1
stays constant.
c 1
stays the same. may increase
or decrease.
a 1
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
Thermodynami
cs.
0
increases 8x. increases 16x.
0
3 e7 5.2 e8
0
excess reactant product yield
b 1
reactant ratio fresh-feed
conversion b 1
Latent Heat of
Condensation
Net Calorific
Value
0
moisture volatile
combustible
matters
0
Ultimate
analysis
Elemental
analysis
0
O2-free basis N2-free basis
0
Dulong's
formula
Oxygen
unaccounted
for equation
0
32.48 42.56 0
2.38 6.13
0
absolute
humidity of 0.05
60% saturation
0
PhP 434.16 PhP 450
0
0.03 0.05
0
4350 6000
0
9.5 17
0
0.9 0.92
0
51.2 22.76
0
7.86 23.1
0
1/conc 1/conc-time 0
2 1.5
0
adding a
catalyst
removing the
products of the
reaction
0
the net equation the rate law.
0
does not
depend on the
initial
concentrations
is not a
characteristic
of the reaction
0
8 16
0
nature of
reactants
temperature
0
> 0 <0 0
log Ca vs
reciprocal time
1/Ca vs time
0
lof Ca vs time Ca vs time
0
-ra = k Ca -ra = k Cb^2
0
Law of Mass
Action
Second Law of
Thermo
0
proportional to
initial conc
inversely
proportional to
initial conc
0
85.3 99.1
0
231 s 768 s
0
19.1 min 10.4 min
0
8.33 9.33
0
52.63 m 56.23 m
0
0.3394 0.6197
0
300 527
0
0.327 0.237
0
12.7 20.7
0
9550 10150
0
Cao/(1-2m) Cao/2
0
37.1 31.8
0
1/32 1/64
0
2 4
0
2 4
0
2 4
0
the suction
pressure is too
high
suction is lost
0
16.9 87.2
0
1.72 1.89
0
21 58.3
0
PhP 7000 PhP 12000
0
2 2exp2
0
velocity head dynamic head
0
surface tension drag coefficient
0
63 85
0
4x3x6 3x2x13
0
248 320
0
8 10
0
77 94
0
25 30
0
there is a
vacuum
when the liquid
level is high
0
efficiency none of the
given choices
0
shell and tube extended
surfaces
0
0.89 0.92
0
17 m
2
20 m
2
0
255.65 214.65
0
less resistance
to heat flow
a porous
structure 0
accounts for
additional
resistance to
heat flow
none of these
0
Peclet number Prandlt number
0
heat transfer in
turbulent flow
heat transfer in
laminar flow 0
contaminated
cooling
surfaces
polished
surfaces 0
for fluids in
turbulent flow
when
Grashhoff
number is very
important
0
pressure-
vacuum
vacuum
0
0.76 0.65
0
1220 mm 2400 mm
0
reduction ratio average
particle
diameter
0
0.7 0.6 0
sorting centrifugation
0
concentration electric field
0
concentration electric field 0
thermal and
ordinary
thermal and
Knudsen
0
J
A
= J
B
N
A
= -cD
AB
dx
A
/dz
0
buffer region viscous sub-
layer
0
relative time relative position
0
Bi Pe
0
the interface either of the
bulk phases
0
in the liquid
phase
in either film
0
water-cooling in
a cooling tower
heating of air
0
dehumidificatio
n and removal
of sensible heat
dehumidificatio
n by
condensing
water vapor in
a refrigerator
0
adiabatic
saturation
temperature
dew point
temperature
0
2 50
0
free moisture unbound
moisture
0
critical free
moisture
content
equilibrium
moisture
content
0
the solute
concentration of
the liquid and
gas phase are
equal
the solute
concentration
of the gas is
greater than
the liquid
0
1.77exp
-6
1.22 exp
-6
0
10050 11570
0
2.3 hr 2.9 hr
0
cm^
3
/sec cm^
2
/sec^
2
0
50 150
0
sieve-plate
column
wetted wall
column
0
remains
unchanged
0
vacuum
evaporator
falling film
evaporator
0
convective
mass transfer
all of these
0
increase the
pressure drop
in the tower
reduce the flow
rate across the
column
0
the gas flow
rate is
maximum
the number of
stages is
infinite
0
0.51 0.68
0
0.71 0.65
0
20.9 22.4
0
0.87 min 1.18 min
0
equal to shear
rate of
deformation.
a linear
function of the
shear rate of
deformation.
d 1
incompressible incompressible
& inviscid
d 1
1.84 0.25
0
streamline none of these
c 1
101.3 61
0
mean linear
velocity
local velocity
d 1
venturi rotameter
b 1
coefficient of
discharge
cross-sectional
area
0
velocity head static head c 1
< 5 0 0
Centrifugal
pump
Diaphragm
pump
0
34 ft 8 ft
0
needle gate 0
resemble
closely to
isothermal
compression
are easy to
control
0
1.5 5 b 1
fans compressors
d 1
viscosity surface tension
d 1
0.189 kg 0.198 kg
0
continuous
distillation
without reflux
distillation
operating at
total reflux
0
less number of
trays
high reflux ratio
0
an irreversible
phenomenon
always in
equilibrium c 1
both A and B either A or B
because these
two mean the
same thing
0
results due to
low gas velocity
is due to
bubble cups 0
feed phase and
solvent phase
overflow and
underflow 0
Absorption Stripping
d 1
3-heptanol toluene
0
P.D. No. 232 P.D. No. 826 0
it depends not governed
by law 0
21 23
0
industrial
applicability
a technical
solution to
problem
0
request claims
0
Environmental
Impact
Assessment
Environmental
Critical Project 0
petroleum detergents
0
it poisons the
catalyst in the
refining process
all that are
mentioned
a 1
builders perfume
c 1
copolymerizatio
n
natural
b 1
polymerization alkylation
d 1
retarders fillers a 1
opacifier filler a 1
cellulose waste
c 1
evaporation crystallization
c 1
bleaching calendering b 1
xylem lignin d 1
Dichlorodipheny
ldichlorobutane
diphenyldichlor
otriphenylbutan
e
c 1
oxidation purification b 1
thinner anti-skinning
agent
a 1
increase
atmospheric
oxidation
give elasticity
and prevent
cracking of the
film
d 1
an inorganic
polymer
thermosetting
plastic
c 1
vulcanization calendering
d 1
pesticide polyester a 1
polyester pigment
b 1
0.6784 0.7652
0
state function state
description of a
system
b 1
a reversible and
constant
entropy process
constant
enthalpy
process
0
+1.57 kJ +2.27 kJ
0
reversible irreversible
c 1
carnot
efficiency
Helmholtz free
energy
c 1
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.
0
less than 0.75 in between
0.84 and 0.90
0
must be
economically
viable
exist at a high
pressure at the
condensation
temperature
0
isothermal isentropic
a 1
equilibrium start of the
process
c 1
one isochoric,
one isobaric,
and two
adiabatic
process
one isothermal,
one isochoric
and two
adiabatic
process
0
superficial
velocity
specific volume
0
Mach number Power number
0
0.2 0.124
0
z axis is defined
vertical &
downward in
direction
normal surface
forces & gravity
are the only
forces involved
0
process
variable
load variable
0
emf resistance
0
time velocity d 1
17kPa/K 0.06kPa/K
0
Rise time overshoot
b 1
37.1 lb/s 317 lb/s
0
52581 393308
0
1.5 inch 2 inches
0
50.5 58.6
0
233 degF 297 degF
0
QUESTION A B
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
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
0.052 0.025
The equation that relates friction factor and Reynold's No.,
f=64/Reynold's No. holds for
smooth pipes laminar and
turbulent flow
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
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 enrichment of the vapor steam as it passes through the column in
contact with the reflux during distillation is called
evaporation stripping
The maximum number of plates for a given distillation system is
obtained at
variable reflux maximum reflux
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
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
**ang kulit
ah! =P
For a cylinder where steady-state radial heat transfer takes place the heat flux is
constant
maximum heat
transfer rate occurs
at the surface
**eh di
nga?
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
Crystallization occurs in a solution that is concentrated
**concentration happens
when the amount of solvent
in a solution is decreased
unsaturated
Mass transfer in a flowing fluid may be correlated by Sherwood, Nusselt
and Reynold's No
Peclet, Reynold's
and Schimdt No
The ratio of the average diameter of the feed to the average diameter
of the product is the
settling ratio discharge ratio
The rate of formation of C for the reaction 2A + B ---> C is found to be
rate=k(A)(B) ***cguro w/c is true ang tanong? Hehe***
the rate of
formation of C is
equal to the rate of
disappearance of B
the order of reactio
is zero **how can u
say so?
A device for increasing the velocity of a fluid in steady flow is a nozzle vent
**ang vent ay butas?
Di sisingaw? Babagal lalo
ang velocity, meh singaw eh.
In steady-state backmix flow reactor, composition is not constant
throughout the
reactor
constant
throughout the
reactor
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
In fractionation, an increase in reflux ratio increases the
number of
theoretical plates
decreases the
reboiler duty
In mass transfer where the solute in the gas phase is very soluble in the
liquid phase ***cguro w/c is true ang tanong? Hehe***
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
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
Which of the following fittings exhibits the highest pressure drop for the
same flow conditions?
90-degree long
radius elbow
**K = 0.45
90-degree standard
elbow
**K = 0.75
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
Which one of the following pipes has the highest relative roughness? 2" diameter
Wrought iron pipe
4" dia Wrought iron
pipe
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
Reactions whereby reactants proceed along several paths and give
different products are
polymeric reactions reversible reactions
Which one among the following materials has the best insulating
property?
window glass wood
An operation where warm vapor mixture is cooled such as by contact
with a liquid resulting in condensation and decreased humidity is
evaporation dehumidification
The pressure exerted on a plane parallel to the direction of flow of a
moving fluid is called
gauge pressure velocity pressure
For mass transfer to take place, there must be a phase change reaction component
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
The diffusity of water in air at 100 deg F in sq.cm./sec is 0.256 0.278
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
5.9 2.5
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
66.6 58.1
When 32 kg of methane is burned completely the theoretical oxygen
required is
16 kg 64 kg
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
32.2 31.4
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 2.18
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
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
0.0378 0.0504
A metallic rod 2 cm in diameter is used as a heating element. The
thermal conductivity is 370 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
4440000 5130000
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
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
74.3 75
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
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
0.1 0.05
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
This type of drier is used for drying pasty materials such as wet filter
cakes and lumpy solids
rotary drier flash drier
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
Unbound moisture in granular and porous solid moves through the
intertices of the solid by a mechanism involving
desorption surface tension
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
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 0.034
In drying at the falling rate period, the rate at which moisture is
removed from the solid material
remains constant increases with time
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
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
0.3 0.8
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
mulitple 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 conposed of 15% oil.
The theoretical number of ideal stages is
3 4
The movement of molecules over a substantial distance is associated
with the transfer of heat by
convection conduction
The mode of heat transfer that can take place in a vacuum is known as convection conduction
The overall conductance for a composite material in series is equal to
the
sum of the
individual
conductances
sum of the
individual
conductivities
Film and drop are terms associated with boiling condensation
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.
99.95 415.7
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.
97 242
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
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
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 evpaorator 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.
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
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 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?
10.92 9.12
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 38
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 9
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?
72.2 28.7
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?
0.492 0.429
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 h of 1000 Btu/hr-sq.ft.-degF,
calculate the inside heat transfer coefficient [Btu/hr-cu.ft-degF].
2173 696
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
Nicotine is to be extracted from water using kerosene. If 100 lb of a 2%
nicotene solution is extracted once with 200 lb of kerosene, what
percent of the nicotene is extracted? {Equilibrium data: Y[lb
nicotene/lb kerosene] = 0.90X [lb nicotene/lb water]}
64.5 54.6
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.
77.2 150
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 8457
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
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]?
10500 35000
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.
38.1 18.3
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 1644
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
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 84
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]
34.2 27.7
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
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?
113 227
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 0.5
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 )
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.
75.2 55.2
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 the cylinder [W per meter length].
13 272
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].
0.028 0.119
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].
325 300
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
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 18
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].
170 100
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
If the absolute temperature of a gas is doubled, the mean speed of the
gas molecules
is doubled. increases 4 times
When ice cubes melt in a glass of water, the temperature of the
resulting mixture of water and ice
increases. decreases.
In all naturally occurring processes, the entropy of the universe increases. decreases.
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.
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.
A 30 MW geothermal electric power plant uses hot 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 degC 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?
2.5 e8 2.2 e8
The material which remains unchanged in a process is limiting reactant tie substance
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
The heating value measured when water formed from combustion is in
the liquid state.
Gross Calorific
Value
Heat of combustion
In the combustion of solid fuels, the tie element between the feed and
the refuse is the
cooked coal ash
The coal analysis which is based upon the volatilization characteristics
of the fuel is
Proximate analysis Modified analysis
An Orsat analysis of the flue gas when pyrite is roasted is on a SO2-free basis SO3-free basis
The empirical relation which allows one to compute for the net
hydrogen in a given solid fuel is the
Calderwood
equation
Theoretical Oxygen
Equation
The equivalent of 45degTw in the Baume scale is 26.63 28.32
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?
1.2 1.53
Which has the lowest water content? dew point at
20degC
70% RH
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?
Freiht cost is PhP45/tonne.
PhP 405 PhP 424.26
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
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 3750
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
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
0.8 0.85
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 % methane in the fuel gas is
63.25 57.24
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
The unit of k for a 1st order elementary reaction is 1/time conc/time
If the temperature of a chemical reaction is raised by 10 degC, the rate
of reaction is increased by a factor of
4 3
The E of a reaction may be lowered by increasing
temperature
decreasing
temperature
The mechanism of a reaction can sometimes be deduced from the activation
energy
the temperature
dependency of the
rate
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
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 4
The rate of reaction is not influenced by conc of the
reactants
molecularity of the
reaction
The net rate of reaction of an intermediate is 0 2
A reaction is known to be first order in A. A straight line will be obtained
by plotting
log Ca vs time Ca vs time
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
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
It states that the rate of a chemical reaction is proportional to the
activity of the reactants.
Le Chatelier's
principle
Hess' Law
The half life of a material undergoing second order decay is proportional to the
square of the initial
conc
independent of
initial conc
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.
66.8 74.7
A first order reaction has a specific rate constant of 3e-3 per sec. The
half life is
0.0021 s 100 s
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
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
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
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 value of K2 per hour is
0.1697 0.183
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
257 275
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
0.732 0.427
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
10.3 11.4
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 9150
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)
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
43.1 41.3
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
When two centrifugal pumps are connected in series, the discharge
changes by a factor of
1/2 1
When two reciprocating pumps are connected in parallel, the
volumetric capacity of the system changes by a factor of
1/2 1
The pressure drop in a pipeline changes by a factor of _____ when the
velocity of the flowing fluid is doubled.
1/2 1
Cavitation occurs in a centrifugal pump when the discharge
pressure becomes
too high
the discharge valve
is closed
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 13.1
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
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.
0.6 3.58
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
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
The differential height between two points which a fluid has to be
transferred is the
potential head pressure head
The resistance of a layer of fluid to flow over the next layer is measured
by
viscosity friction factor
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 36
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
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.
95 134
If the speed of a centrifugal pump is doubled, the energy requirement
becomes approximately ___ times the original energy requirement.
2 4
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 55
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 20
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
An optimim number of the effects for a given application is a function of
the
capacity economy
A popular type of heat exchanger for cooling large quantities of fluid is
the
double-pipe plate
An evaporator is used to concentrate 10,000 lb/hr of a 20% solution of
NaOH in water at 140
o
F using saturated steam at 25 psia at a rate of
7,000 lb/hr. The OHTC is 275 BTU/hr-ft
2
-
o
F when the pressure in the
vapor is 1.7 psia. The steam economy, SE, is
0.82 0.863
A cross flow heat exchanger uses mixed air at 4 kg/s that enters at 15
o
C
and leaves at 45
o
C. The air cools unmixed water, which enters at 95
o
C
and 0.70 kg/s. The OHTC equals 150 W/m
2
-
o
C. After several months of
operation, a scale resistance of 0.002 m
2
-
o
C/W developed. 16. The heat
transfer area required to accomplish the change is
22.2 m
2
25 m
2
As solution of 28% wt Na
2
SO
4
is to be crystallized 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 120
o
F and cooled to 60
o
F using
cooling water which enters at 50
o
F and leaves at 70
o
F. The crystallizer
has a cooling surface of 3 ft
2
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
285.3 249.3
An insulator should have low thermal
conductivity
high thermal
conductivity
Fouling factor is a dimensionless
quantity
does not provide a
safety factor for
design
Natural convection is characterized by Reynolds number Grashhoff number
The Graetz number is concerned with mass transfer
between a gas and
a liquid
absorption with
chemical reaction
Dropwise condensation occurs on clean and dirt free
surfaces
smooth clean
surfaces
Dietus-Boelter equation for determination of heat transfer co-efficient
is valid
for liquid metals for fluid in laminar
flow
A type of pneumatic conveyor system characterized by a material
moving in an air stream or pressure less than ambient.
fluidizing pressure
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
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
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
The sphericity of cubical particles is 1 0.87
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
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
Ordinary diffusion takes place because of ___ driving force. temperature pressure
What are the two limiting cases of steady-state diffusion? UMD and EMD ordinary and
Knudsen
Which of the following is not true in (binary) equimolar counter-
diffusion?
D
AB
= D
BA
c = c
A
+ c
B
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
In unsteady-state mass transfer, the quantity (D
AB
t/r
m^
2
) is referred to as
unaccomplished
change
relative resistance
What is the equivalent of Prandtl number in convective mass transfer? Sc Sh
If k
x
> k
y
, then the controlling phase is the liquid phase the gas phase
In two-phase mass transfer, equilibrium may exist at the interface in the gas phase
Which of the following processes may always be regarded as a constant-
humidity process?
cooling of air air conditioning
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
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
The moisture content of a solid is given as 50% wet basis. What is the
moisture content, dry basis?
0.5 1
The moisture that can be removed by drying is called equilibrium
moisture
bound moisture
Falling-period in drying terminates at the end of constant-
rate period
origin of R vs X plot
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
He and N
2
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-m
2
is
2.35 exp
-5
2.44exp
-5
100 m
3
/hr of air at 60C and 20% RH is needed for a chemical reactor.
This will be obtained from process air at 60C 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 8490
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
The unit of volumetric diffusivity is
cm^
2
/sec
cm/sec
If reflux to a distillation column is 100 moles/hr, when the overhead
product rate is 50 moles/hr. the reflux ratio is
0.5 2
Which of the following provides maximum contact surface for a liquid-
vapour system?
packed lower bubble-cup plate
column
In extraction, as the temperature increases, the area of heterogeneity
(area covered by bimodal curve)
decreases increases
The suitable evaporator for concentration of foaming liquids is long tube
evaporator
short tube
evaporator
Macroscopic transfer of mass between moving fluid and surface which
is of different concentration is called
molecular diffusion unsteady-state
diffusion
For a packed column the main purpose of packing is to strengthen the
column
increase the surface
area
In a gas absorption operation, when the operating line crosses the
equilibrium curve
the NTU is zero the liquid flow rate
is maximum
Methanol diffuses in 0.15 cm stagnant film of 1:1 mole mixture of
hydrogen and CO
2
at 100
o
C 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 CO
2
at 0
o
C and 1 atm in cm
2
/s is
0.15 0.31
Gaseous reactant A decomposes according to the reaction A --> 3R (-r
A
=
0.5 C
A
mole/L-min). The feed, which consists of 70% A and 30% inert,
enters a 1.5-m
3
CSTR at a flow rate of 150 L/min. 4. If CA0 = 0.30
mole/L, what is the conversion, XA?
0.92 0.86
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?
14.7 18.5
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
For Newtonian fluids, the shear stress is constant. inversely
proportional to rate
of deformation.
An ideal fluid is one that is compressible incompressible &
viscous
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 [ft
3
/s] in the main
pipe is
10.58 5.29
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
Air at 25
0
C [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?
350 155
A simple pitot tube measures acoustical velocity superficial velocity
Which of the following meters will have the highest permanent
pressure loss?
pitot tube orifice
In the flow meter equation, Y, indicates the mass flow rate compressibility
factor
The loss due to sudden contraction is proportional to velocity turbulence
Stokes law is valid when the particle Reynolds number is < 1 > 1
Priming needed in a Reciprocating
pump
Gear pump
Maximum theoretical suction lift for water at 60F by a centrifugal
pump is 34 ft. The same for water at 200F will be
40 ft 37 ft
The most economical valve for use with large diameter pipes. butterfly globe
Multistage compressors are used in industry because, they reduce the cost of
compressor
reduce the size
requirement
For ideally incompressible fluid, the mach number will be 0 1
of the following produces maximum pressure difference for
transportation of gases?
vacuum pumps blowers
The fluid property which matters for falling rain drops to acquire
spherical shape is its
pressure height of descend
A wastewater solution having a volume of 1000 L contains 0.21 kg
phenol/m
3
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
The overhead product composition decreases with time in batch distillation
with reflux
continuous
distillation with
reflux
For a binary mixture with low relativity, continuous rectification to get
pure products will require
low reflux ratio small cross-section
Chemisorption is the same as van der
Waals
characterized by
adsorption of heat
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
Weeping in distillation or absorption column increases tray
efficiency
provides larger
surface for mass
transfer
What are the two contacting phase in leaching? extract phase and
raffinate phase
solvent phase and
solute phase
Hydrogen sulfide is removed from water by contacting the solution with
warm air. The operation is
Distillation Leaching
Disregarding the cost, which is the best solvent for the extraction of
acetic acid from an aqueous solution at 25deg C?
caproic acid chloroform
Professional Regulations Commission was created under P.D. No. 223 P.D. No. 233
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
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 19
Which of the following is not a requirement for utility model
registration?
inventive step novelty
A section of the patent application containing detailed descriptions of
the benefits obtained from using the invention is called the
disclosure abstract
A document issued by the DENR secretary indicating that the proposed
project will cause significant negative environmental impact.
Environmental
Impact Statement
Environmental
Compliance
Certificate
In the Philippines, sulfur for sulfuric acid manufacturing is sourced from
_______ industry.
paper cement
Sulfur is undesirable in petroleum because it causes engine
knocking
it increases the
boiling pt of fuel
Materials added to detergent formulation to enhance cleaning
performance by exhibiting synergistic cleaning effect with surfactant.
fillers brighteners
Polyethylene is an example of _____________ polymerization condensation addition
Principal chemical conversion in the production of resin from monomer. condensation hydration
Carbon black is added to rubber compounding as activator curing agent
The binder for all the powder materials of paint pigment vehicle
A fibrous material left after cane sugar has been milled is commonly
called as
bagasse pulp
Molasses is a by product of raw sugar from the ______ process milling extraction
Kraft process is a common name for sulfate pulping sulfite pulping
Water insoluble cell binders of wood pulp cellulose
DDT means Diphenyldichlorotri
phenylethane
dichlorodiphenyldic
hloroethane
Rancidity of oil can be reduced by decoloration hydrogenation
Varnish does not contain pigment dryer
Plasticisers are added to paints to make it corrosion
resistant
make glossy surface
Silicone is thermoplastic a monomer
The process involved in converting rubber into a thin sheet or coating it
on fabric is called
extrusion mastication
Alkyl benzene sulfonate (ABS) is a detergent rubber
Neoprene is a monomer synthetic rubber
Steam enters an adiabatic turbine at 10 MPa and 500
deg
C 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.
0.2348 0.3216
Work is a property of the
system
path function
Throttling process is a reversible and
isothermal process
an irreversible and
constant entropy
A sample consisting of 1.00 mole of Argon gas is expanded isothermally
and reversibly at 0C from 22.4L to 44.8L. The heat absorbed by the
system is
0 +1.13 kJ
Maximum work can be obtained from a system when the change taking
place in it is
isothermal adiabatic
The ratio of work performed by a system and the heat it absorbed from
a reservoir is referred to
Entropy Gibbs free energy
According to the first law of thermodynamics Energy is neither
lost nor gained in
any energy
transformation.
Perpetual motion is
possible.
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
In choosing the refrigerant, the fluid must have the following
characteristics, except
environmentally
benign
has a vapor
pressure less than
atmospheric
Coolers and boilers are ordinarily operated at ________ condition. isobaric isenthalpic
For an isolated system, maximum entropy will occur at half-life critical condition
A carnot cycle consists of two isothermal and
two adiabatic
process
two isochoric and
two adiabatic
process
This is also known as the volume fraction of the voids in packed beds. sphericity porosity
A measure of the ratio of the drag force acting on a unit area of the
impeller & the inertial stress.
Froude number Reynolds number
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 2
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
Which of the following can be adjusted by human operator in a closed
feedback control loop?
set point controller output
The thermocouple is based on the Seebeck effect which states that a/an
_____ is generated when opposite junction of certain dissimilar pairs of
wires are exposed to different temperatures.
current temperature
Dead time is a function of distance and momentum acceleration
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
The parameter which completely describes the behavior of the
response to a disturbance of a second order system is the
Time constant damping coefficient
C D Comments!
globe valve orifice
a
! Un na nga ang gate valve. =P
0.03 0.038
E
! The correct answer is about 0.0095 from perry 8th fig 6.9 pge 6-
10 tingnan nyu pa
turbulent flow
only
laminar flow only
X
! Meron gang f=64/Re? baka f = 12/Re eto eh "Hagen-Poiseuille
Equation" for SMOOTH TUBES & LAMINAR FLOW from perry 8
same page ng nasa taas.
equal to the heat
transfer coefficient
equivalent to the
resistance offerred
by the pipe
equal to the heat
transfer coefficient of
the steam
d
xxx
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.
b
xxx
rectification fractionation
c
xxx
minimum reflux optimum reflux
c
xxx
mol/liter/min liter/mol/min
E
! 1/time
k = (Volume
(order -1)
) / (Concentration
(order -1)
) x time
no effect significant effect
c
! Eh constant nga ung temp nung isang stream..=P btw.. T
lm
=
[T
(side a)
- T
(side b)
] / ln [T
(side a)
/ T
(side b)
] a------
--------------->b a--------------------->b a-----
---------------->b a<---------------------b
the heat transfer
is
constant **panu pag iba na
ang heat transfer area?
the temperature is
uniform throughout
the cylinder
**sinong
nanay mo?
a
! Steady State daw ang heat transfer so steady o constant din
ang Heat Flux. Bakit hindi ung c? kasi di pwedeng sabihin na heat
transfer eh constant kasi ang heat transfer eh q lang.
Samantalang ang Heat Flux eh q/A.
***Amount of Heat Transfer = Heat Flux x Area of Heat Transfer ***
*** q = (q/A) x A ***
transition plate bubble plate
d
xxx
supersaturated saturated
c
! Sturated --> Solute = Solvent
Unsaturated --> Solute < Solvent
Supersaturated --> Solute > Solvent
**based on solubility***
Sherwood,
Reynold's and
Schimdt No
Prandtl, Schimdt and
Reynold's No c
! Look at p 5 - 63 to 5 -82 of perry 8th. Specifically, note the
dimensionless numbers being used at every MTC formula.
N
sh
N
re
N
sc
reduction ratio classification ratio
c
! Malamang =P
the value of k is
independent of
the initial
concentrations of
A and B
the reaction cannot
proceed **isa ka pa^^
c
! Kelan ga naging dependent ang k sa initial concen ng kahit na
alin sa reaction? Sa Temperature lang dependent ang k**. Kaya
nga ang tawag sa k ay "specific rate constant" dahil specific sya
sa isang temp at sa isang reaction at sya ay constant! Hehe
**from Arrhenius eqn :
lnk = - (E
A
/ R) (1 / T) + lnk
o
orifice
**pabibilisin
nga, haharangan pa xD
venturi
**meter? hehe
a
! Nozzle - ex. Pipe na papaliit ang diameter, papaliit din malamang
ang cross sectional area, at papabilis ang velocity ng fluid.
***flow of incompresible fluids***
mass flowrate = density x Area x velocity
a function of time not uniform
throughout the reactor
and varies from time to
time
b
! Bacmix Reactor is another name for CSTRs (Constantly Stirred
Tank Reactors) wherein ther is a constant composition
throughout which is assumed due to constant stirring.
book value market value
b
xxx
increases the
amount of
distillate
increases the
condenser duty
?
xxx
the gas phase
resistance is
negligible
the ratio of gas phase
resistance to liquid
resistance is
approximately zero
?
xxx
Peclet, Stanton
and Prandtl Nos
Schimdt, Peclet and
Friction Nos b
! Sila yung gamitin sa Heat Transfer by convection. See perry 8th
p 5.7, Heat transfer by conduction.
N
u
N
re
N
Pr
45-degree
standard elbow
**K = 0.35
square-corner elbow
**K = 1.3 d
! The higher the K (additional friction loss) the higher the
pressure drop. See page 6 -18 perry 8th.
compressor accumulator
1" dia Drawn
tubing
4" dia Riveted steel
pipe
through each
material is
inversely
proportional to
the thickness of
the material
is constant throughout
the series of materials
parallel reactions consecutive reactions
air concret
b
humidification extraction
b
tangential
pressure
static pressure
b
concentration
gradient
momentum gradient
c
113 deg F 146 deg F
1.484 0.581 b
1.5 0.6
33.4 54.4
128 kg 32 kg
c
26.4 57.8
1.5 2.75
over 20 million over 2 but less than 3
0.0454 0.0252
6930000 2040000
saturation
temperature
dry-bulb temperature
75.26 78.5
the temperature
of the air can also
be maintained
constant
increase in the
humidity of the air is
insignificant
0.02 0.01
equilibrium
moisture content
critical moisture
content
c
tray drier freeze drier
c
air flow
perpendicular to
the surface of the
solid
air flow parallel to the
solid surface
surface renewal moisture diffusivity
d
2.129 hrs 3.42 hrs
0.01155 0.00116
decreases with
time
no drying takes place
to use cross flow
evaporation
to use spray
percolators
1.5 2.3
5 6
radiation all of A, B and C
a
radiation all of A, B and C
c
inverse of the total
resistance
sum of the individual
resistances c
evaporation all of A, B and C b
451.7 475.1
5800 139200
5.51 m 4.14 m
966 kg 534 kg
85.8 sq.m. 88.5 sq.m.
14 kPa zero gauge
4.72 3.03
39 40
8 7
27.8 22.7
0.294 0.249
577 241
13.76 16.28
46.5 45.6
227.2 300
11994 20451
40130 45500
13.8 5
1163 19.4
4.67 2
95 100
7 0.52
31.7 37.1
851 900
0.75 1
[B]=0.4(1-0.5x )/(1-
x )
[B]=0.2
25.2 20
3478 3750
0.714 6.01
100 25
13943 W 19343 W
23 33
38 0.038
both contain the
same no of air
molecules
increases by about
40%
decreases.
stays constant.
c
stays the same. may increase or
decrease.
a
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.
increases 8x. increases 16x.
3 e7 5.2 e8
excess reactant product yield b
reactant ratio fresh-feed conversion
b
Latent Heat of
Condensation
Net Calorific Value
a
moisture volatile combustible
matters
b
Ultimate analysis Elemental analysis
O2-free basis N2-free basis b
Dulong's formula Oxygen unaccounted
for equation
32.48 42.56
2.38 6.13
absolute humidity
of 0.05
60% saturation
PhP 434.16 PhP 450
0.03 0.05
4350 6000
9.5 17
0.9 0.92
51.2 22.76
7.86 23.1
1/conc 1/conc-time a
2 1.5
adding a catalyst removing the products
of the reaction
the net equation the rate law.
does not depend
on the initial
concentrations
is not a characteristic
of the reaction
c
8 16
d
nature of
reactants
temperature
> 0 <0
log Ca vs reciprocal
time
1/Ca vs time
lof Ca vs time Ca vs time
-ra = k Ca -ra = k Cb^2
Law of Mass
Action
Second Law of Thermo
c
proportional to
initial conc
inversely proportional
to initial conc
85.3 99.1
231 s 768 s
19.1 min 10.4 min
8.33 9.33
52.63 m 56.23 m
0.3394 0.6197
300 527
0.327 0.237
12.7 20.7
9550 10150
Cao/(1-2m) Cao/2
37.1 31.8
1/32 1/64
2 4
2 4
2 4
the suction
pressure is too
high
suction is lost
16.9 87.2
1.72 1.89
21 58.3
PhP 7000 PhP 12000
2 2exp2
velocity head dynamic head
surface tension drag coefficient
63 85
4x3x6 3x2x13
248 320
8 10
77 94
25 30
there is a vacuum when the liquid level is
high
efficiency none of the given
choices
shell and tube extended surfaces
0.89 0.92
17 m
2
20 m
2
255.65 214.65
less resistance to
heat flow
a porous structure
a
accounts for
additional
resistance to heat
flow
none of these
Peclet number Prandlt number b
heat transfer in
turbulent flow
heat transfer in laminar
flow d
contaminated
cooling surfaces
polished surfaces
c
for fluids in
turbulent flow
when Grashhoff
number is very
important
pressure-vacuum vacuum
d
0.76 0.65
1220 mm 2400 mm
reduction ratio average particle
diameter
c
0.7 0.6 a
sorting centrifugation
a
concentration electric field
concentration electric field c
thermal and
ordinary
thermal and Knudsen
J
A
= J
B
N
A
= -cD
AB
dx
A
/dz
buffer region viscous sub-layer
relative time relative position
Bi Pe
the interface either of the bulk
phases
in the liquid phase in either film
water-cooling in a
cooling tower
heating of air
dehumidification
and removal of
sensible heat
dehumidification by
condensing water
vapor in a refrigerator
adiabatic
saturation
temperature
dew point temperature
2 50
b
xxx
free moisture unbound moisture
c
critical free
moisture content
equilibrium moisture
content
the solute
concentration of
the liquid and gas
phase are equal
the solute
concentration of the
gas is greater than the
liquid
1.77exp
-6
1.22 exp
-6
10050 11570
2.3 hr 2.9 hr
cm^
3
/sec cm^
2
/sec^
2
50 150
sieve-plate column wetted wall column
remains
unchanged
vacuum
evaporator
falling film evaporator
convective mass
transfer
all of these
increase the
pressure drop in
the tower
reduce the flow rate
across the column
the gas flow rate is
maximum
the number of stages is
infinite
0.51 0.68
0.71 0.65
20.9 22.4
0.87 min 1.18 min
equal to shear rate
of deformation.
a linear function of the
shear rate of
deformation.
d
incompressible incompressible &
inviscid
d
1.84 0.25
streamline none of these
101.3 61
mean linear
velocity
local velocity
d
venturi rotameter
b
coefficient of
discharge
cross-sectional area
velocity head static head c
< 5 0
Centrifugal pump Diaphragm pump
34 ft 8 ft
needle gate
resemble closely
to isothermal
compression
are easy to control
1.5 5 b
fans compressors
d
viscosity surface tension
d
0.189 kg 0.198 kg
continuous
distillation without
reflux
distillation operating at
total reflux
less number of
trays
high reflux ratio
an irreversible
phenomenon
always in equilibrium
c
both A and B either A or B because
these two mean the
same thing
results due to low
gas velocity
is due to bubble cups
feed phase and
solvent phase
overflow and
underflow
Absorption Stripping
d
3-heptanol toluene
P.D. No. 232 P.D. No. 826
it depends not governed by law
21 23
industrial
applicability
a technical solution to
problem
request claims
Environmental
Impact Assessment
Environmental Critical
Project
petroleum detergents
it poisons the
catalyst in the
refining process
all that are mentioned
a
builders perfume
c
copolymerization natural
b
polymerization alkylation
d
retarders fillers a !
opacifier filler a !
cellulose waste
c
!
evaporation crystallization c
bleaching calendering b
xylem lignin d
Dichlorodiphenyldi
chlorobutane
diphenyldichlorotriphe
nylbutane
c
oxidation purification b
thinner anti-skinning agent a
increase
atmospheric
oxidation
give elasticity and
prevent cracking of the
film
d
an inorganic
polymer
thermosetting plastic
c
vulcanization calendering
d
pesticide polyester a
polyester pigment b
0.6784 0.7652
state function state description of a
system
b
a reversible and
constant entropy
process
constant enthalpy
process
+1.57 kJ +2.27 kJ
reversible irreversible
c
carnot efficiency Helmholtz free energy
c
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.
less than 0.75 in between 0.84 and
0.90
must be
economically
viable
exist at a high pressure
at the condensation
temperature
isothermal isentropic
a
equilibrium start of the process c
one isochoric, one
isobaric, and two
adiabatic process
one isothermal, one
isochoric and two
adiabatic process
superficial velocity specific volume
b
Mach number Power number
0.2 0.124
z axis is defined
vertical &
downward in
direction
normal surface forces
& gravity are the only
forces involved
process variable load variable
emf resistance
time velocity
17kPa/K 0.06kPa/K
Rise time overshoot
b
xxx
legend:
X = something wrong with the question
E = answer is not on the 4 choices
xxx = bakit kaya?
if there is any revisions on answers, kindly inform me. Itama nyu
naman pag mali ako. Baka nagiimagine lang ako ng formula.
Hehe
xxx
puro to kalokohan ha.. Hehe
! I found this thing on August 8, 09 and I started answering the
blank parts and correcting the wrong ones since then.
---------------------------------------------------------------boja---
la lang ^^