Chemical Engineering Review Questions[1]

CHEMICAL ENGINEERING REVIEW QUESTIONS NO 1

QUESTION 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 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 The equation that relates friction factor and Reynold's No., f=64/Reynold's No. holds for Oil flows under laminar conditions inside a steam heated copper pipe. The overall heat transfer coefficient is approximately

A gate valve

B butterfly valve

C globe valve

orifice

0.05

0.03

0.03

0.04

smooth pipes

laminar and turbulent flow the average between the heat transfer coefficient of the steam and that of oil

turbulent flow only

laminar flow only

equal to the heat transfer coefficient equivalent to the resistance offered by the pipe

equal to the heat transfer coefficient of the steam

5

In multi-stage liquid-liquid extraction with partially miscible solvents

the minimum number of stages occur when the operating lines are parallel.

the minimum number of stages occur when the tie line coincides with an operating line.

the amount of solvent used must be enough to form 2 phases.

6

The enrichment of the vapor steam as it passes through the column in contact with the reflux during distillation is called The maximum number of plates for a given distillation system is obtained at The correct unit for the specific rate constant for the reaction A--->B determined to be first order is

the extraction must be done to form cocurrently in order to minimize the extraction. evaporation

stripping

rectification

fractionation

variable reflux

maximum reflux

minimum reflux

optimum reflux

square liter/square mol/min

square liter/square mol/square min

mol/liter/min

liter/mol/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 For a cylinder where steady-state radial heat transfer takes place

large effect

little effect

no effect

significant effect

the heat flux is constant

maximum heat transfer rate occurs at the surface

the heat transfer is constant

the temperature is uniform throughout the cylinder

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 Crystallization occurs in a solution that is Mass transfer in a flowing fluid may be correlated by

separation plate

theoretical plate

transition plate

bubble plate

concentrated Sherwood, Nusselt and Reynold's No

unsaturated Peclet, Reynold's and Schimdt No

supersaturated Sherwood, Reynold's and Schimdt No

saturated Prandtl, Schimdt and Reynold's No

The ratio of the average diameter of the feed to the average diameter of the product is the The rate of formation of C for the reaction 2A + B --> C is found to be rate = k(A)(B)

settling ratio

discharge ratio

reduction ratio

classification ratio

the rate of formation of C is equal to the rate of disappearance of B nozzle

the order of reactio is zero

the value of k is independent of the initial concentrations of A and B orifice

the reaction cannot proceed

not constant throughout the reactor

constant throughout the reactor

a function of time

net value

salvage value

book value

not uniform throughout the reactor and varies from time to time market value

2

3 4

7 8

9

10

11

12 13

14 15

16 17

18

A device for increasing the velocity of a fluid in steady flow is a In steady-state backmix flow reactor, composition is

The amount of money obtainable from the sale of used property over and above any changers involved in removal and sale is called

equal to the heat transfer coefficient of the oil

vent

D

venturi

CHEMICAL ENGINEERING REVIEW QUESTIONS

1

19

In fractionation, an increase in reflux ratio

increases the number of theoretical plates

decreases the reboiler duty

increases the amount of distillate

increases the condenser duty

20

In mass transfer where the solute in the gas phase is very soluble in the liquid phase

the gas phase resistance is approximately equal to the total resistance

the gas phase resistance is negligible

the ratio of gas phase resistance to liquid resistance is approximately zero

21

Heat transfer in turbulent flow may be described through an empirical equation correlating

the ratio of liquid phase resistance to the overall resistance is close to unity Nusselt, Stanton and Reynold's Nos

Nusselt, Prandtl and Reynold's Nos

Peclet, Stanton and Prandtl Nos

Schimdt, Peclet and Friction Nos

22

Which of the following fittings exhibits the highest pressure drop for the same flow conditions? 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 Which one of the following pipes has the highest relative roughness? In steady-state heat transfer through a series of materials with varying resistances, the heat transfer rate

90-degree long radius elbow switching bank

90-degree standard elbow vent

45-degree standard elbow compressor

square-corner elbow

2" diameter Wrought iron pipe decreases towards the direction of heat transfer

4" dia Wrought iron pipe varies with the thermal conductivity of each material

1" dia Drawn tubing

Reactions whereby reactants proceed along several paths and give different products are Which one among the following materials has the best insulating property? An operation where warm vapor mixture is cooled such as by contact with a liquid resulting in condensation and decreased humidity is The pressure exerted on a plane parallel to the direction of flow of a moving fluid is called For mass transfer to take place, there must be a

polymeric reactions

reversible reactions

through each material is inversely proportional to the thickness of the material parallel reactions

4" dia Riveted steel pipe is constant throughout the series of materials

window glass

wood

air

consecutive reactions concret

evaporation

dehumidification

humidification

extraction

gauge pressure

velocity pressure

tangential pressure

static pressure

phase change

reaction component

concentration gradient

momentum gradient

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 The diffusity of water in air at 100 deg F in sq.cm./sec is 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 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 When 32 kg of methane is burned completely the theoretical oxygen required is 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 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 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

212 deg F

80 deg F

113 deg F

146 deg F

0.26

0.28

1.48

0.58

5.90

2.50

1.50

0.60

66.60

58.10

33.40

54.40

16 kg

64 kg

128 kg

32 kg

32.20

31.40

26.40

57.80

4.00

2.18

1.50

2.75

over 100,000 but less than a million

over 100 but less than 200

over 20 million

over 2 but less than 3

23

24 25

26 27 28

29 30 31

32 33

34

35 36

37

38

accumulator


2

original reaction by a factor of 39

40

41

42

43

44

45 46 47

48

49

50

51 52

53

Water at 100 deg F is flowing through a straight 4in 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 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 This is a steady state temperature reached by a small amount of liquid evaporating into a large amount of unsaturated vapor-gas mixture. 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 In adiabatic humidification, it is possible to maintain the temperature of water constant since

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 The portion of water in the wet solid that cannot be removed by the air in its contact is called This type of drier is used for drying pasty materials such as wet filter cakes and lumpy solids In the constant-rate period, the rate of drying is established by

Unbound moisture in granular and porous solid moves through the intertices of the solid by a mechanism involving 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 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 In drying at the falling rate period, the rate at which moisture is removed from the solid material 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 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

0.04

0.05

0.05

0.03

4440000.00

5130000.00

6930000.00

2040000.00

wet-bulb temperature

dew point

saturation temperature

dry-bulb temperature

74.30

75.00

75.26

78.50

according to the phase rule, the degrees of freedom is 3 0.10

the system can be well insulated from the surroundings

the temperature of the air can also be maintained constant

increase in the humidity of the air is insignificant

0.05

0.02

0.01

free moisture

final moisture content

rotary drier

flash drier

equilibrium moisture content tray drier

critical moisture content freeze drier

a balance of the heat requirements for evaporation and the rate at which heat reaches the surface desorption

the internal movement of moisture beneath the surface of the solid

air flow perpendicular to the surface of the solid

air flow parallel to the solid surface

surface tension

surface renewal

moisture diffusivity

0.542 hrs

1.846 hrs

2.129 hrs

3.42 hrs

0.12

0.03

0.01

0.00

remains constant

increases with time

decreases with time

no drying takes place

to reduce the solid to the smallest size feasible 0.30

to use counter current operation

to use cross flow evaporation

to use spray percolators

0.80

1.50

2.30


3

underflow leaving the extraction stage in %wt oil is 54

55 56 57

58 59

60

61

62

63

Tung meal containing 55% oil is to be extracted at the rate of 4000 lb per hour using n-hexane containing 5% oil as solvent. A countercurrent multiple stage extraction system is to be used. The meal retains 2 lb of solvent per pound of oil free meal while the residual charge contain 0.11 lb oil per lb oil free meal while the product is composed of 15% oil. The theoretical number of ideal stages is The movement of molecules over a substantial distance is associated with the transfer of heat by The mode of heat transfer that can take place in a vacuum is known as The overall conductance for a composite material in series is equal to the

3.00

4.00

5.00

6.00

convection

conduction

radiation

all of A, B and C

convection

conduction

radiation

all of A, B and C

sum of the individual conductances

sum of the individual conductivities

inverse of the total resistance

sum of the individual resistances

Film and drop are terms associated with 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-ftdegF 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. 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. 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. 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. An evaporator, working at atmospheric pressure, is to concentrate a solution from 5% to 20% solids at the rate of 1.25 kg/s. The solution which has a specific heat of 4.18 kJ/kg-K is fed to the evaporator at 295K and boils at 380K. Dry saturated steam at 240 kPa is fed to the calandria and the condensate leaves at the temperature of the condensing steam. If the heat transfer coefficient is 2.3 kW/sq.m-K, what is the required area of heat transfer surface. The latent heat of vaporization maybe taken as the same as that of water.

boiling 99.95

condensation 415.70

evaporation 451.70

all of A, B and C 475.10

97.00

242.00

5800.00

139200.00

185.5 m

11.02 m

5.51 m

4.14 m

4301 kg

1500 kg

966 kg

534 kg

55.8 sq.m.

58.5 sq.m.

85.8 sq.m.

88.5 sq.m.


4

64

65

66

67

68

69

70

71

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. 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? 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% metaxylene and 14% para-xylene? The data are given as mole percent. 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? 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? 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? Forty-five pounds per minute of water is heated from 60 to 180 deg F in a 5/8 in., 16 BWG heat exchanger tube. If the steam condensing at 260 deg F, on the outside of the tube gives an hо of 1000 Btu/hr-sq.ft.-degF, calculate the inside heat transfer coefficient [Btu/hr-cu.ft-degF]. 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.

115 kPa

101.3 kPa

14 kPa

zero gauge

10.92

9.12

4.72

3.03

37.00

38.00

39.00

40.00

10.00

9.00

8.00

7.00

72.20

28.70

27.80

22.70

0.49

0.43

0.29

0.25

2173.00

696.00

577.00

241.00

12.54

12.68

13.76

16.28


5

72

73

74

75

76

77

78

79

80

81

Nicotine is to be extracted from water using kerosene. If 100 lb of a 2% nicotine solution is extracted once with 200 lb of kerosene, what percent of the nicotine is extracted? {Equilibrium data: Y[lb nicotene/lb kerosene] = 0.90X [lb nicotine/lb water]} 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. 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? 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]? 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. 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. 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. 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 4inch diameter discharge, calculate the pump efficiency. 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] 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]?

64.50

54.60

46.50

45.60

77.20

150.00

227.20

300.00

3537.00

8457.00

11994.00

20451.00

10500.00

35000.00

40130.00

45500.00

38.10

18.30

13.80

5.00

2951.00

1644.00

1163.00

19.40

2.21

1.35

4.67

2.00

63.00

84.00

95.00

100.00

34.20

27.70

7.00

0.52

11.61

14.24

31.70

37.10


6

82

83

84

85

86

87

88

89

90

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? 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? 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 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. 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]. 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-ftdegF). 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]. 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]. 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/mdegC. 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. 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.

113.00

227.00

851.00

900.00

0.15

0.50

0.75

1.00

[B]=0.4(1-x)/(10.5x)

[B]=0.4(1-x)/(1-1.5x)

[B]=0.4(1-0.5x)/(1-x)

[B]=0.2

75.20

55.20

25.20

20.00

13.00

272.00

3478.00

3750.00

0.03

0.12

0.71

6.01

325.00

300.00

100.00

25.00

1500 W

4392 W

13943 W

19343 W

1.00

18.00

23.00

33.00


7

91

92

93 94

95 96

97

98

99 100

101 102

103 104 105

106

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]. Two rooms A and B of identical volume are connected by an open doorway. The thermostat in the rooms are set so that Ta
170.00

100.00

38.00

0.04

A

B

both contain the same no of air molecules

is doubled.

increases 4 times

increases by about 40%

increases.

decreases.

stays constant.

increases.

decreases.

stays the same.

The application should be rejected because it violates the first law of Thermodynamics.

The application should be rejected because it violates the second law of Thermodynamics.

The application should be rejected because it violates both 1st and 2nd laws of Thermo.

may increase or decrease. The application should be given full consideration because it does not violate any laws of Thermodynamics.

doubles.

quadruples.

increases 8x.

increases 16x.

2.5 e8

2.2 e8

3 e7

5.2 e8

limiting reactant

tie substance

excess reactant

product yield

recycle ratio

combined feed ratio

reactant ratio

fresh-feed conversion

Gross Calorific Value cooked coal

Heat of combustion

Net Calorific Value

ash

Latent Heat of Condensation moisture

The coal analysis which is based upon the volatilization characteristics of the fuel is An Orsat analysis of the flue gas when pyrite is roasted is on a The empirical relation which allows one to compute for the net hydrogen in a given solid fuel is the

Proximate analysis

Modified analysis

Ultimate analysis

Elemental analysis

SO2-free basis

SO3-free basis

O2-free basis

N2-free basis

Calderwood equation

Theoretical Oxygen Equation

Dulong's formula

Oxygen unaccounted for equation

The equivalent of 45degTw in the Baume scale is

26.63

28.32

32.48

42.56

decreases.

volatile combustible matters


8

107

108 109

110

111

112

113

114

115

116 117

118

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? Which has the lowest water content? A contract was made between a buyer and a paper manufacturer for paper containing 5% moisture at PhP450/tonne FOB on specifications that price adjustment will be made if the quality is different. How much should the buyer pay for 1 tonne of paper with 8% moisture content? Freight cost is PhP45/tonne. 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 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 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. 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 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 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 The unit of k for a 1st order elementary reaction is If the temperature of a chemical reaction is raised by 10 degC, the rate of reaction is increased by a factor of The E of a reaction may be lowered by

1.20

1.53

2.38

6.13

dew point at 20degC PhP 405

70% RH

60% saturation

PhP 424.26

absolute humidity of 0.05 PhP 434.16

0.01

0.02

0.03

0.05

2250.00

3750.00

4350.00

6000.00

4.22

8.00

9.50

17.00

0.80

0.85

0.90

0.92

63.25

57.24

51.20

22.76

3.52

6.53

7.86

23.10

1/time 4.00

conc/time 3.00

1/conc 2.00

1/conc-time 1.50

increasing temperature

decreasing temperature

adding a catalyst

removing the products of the reaction

PhP 450

119

The mechanism of a reaction can sometimes be deduced from

the activation energy

the temperature dependency of the rate

the net equation

the rate law.

120

The equilibrium constant in a reversible chemical reaction at a given temperature

depends on the initial conc of the reactants

depends on the conc of one of the products at equilibrium

does not depend on the initial concentrations

is not a characteristic of the reaction

121

If the volume of a reaction vessel is suddenly reduced to one half its original volume the rate will

2.00

4.00

8.00

16.00


9

increase by a factor of 122

The rate of reaction is not influenced by

123 124

The net rate of reaction of an intermediate is A reaction is known to be first order in A. A straight line will be obtained by plotting If the reaction 2A ---> B+C is second order, which of the following plots will give a straight line? 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 It states that the rate of a chemical reaction is proportional to the activity of the reactants. The half life of a material undergoing second order decay is

125 126

127 128

129

130 131

132

133

134

135

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. A first order reaction has a specific rate constant of 3e-3 per sec. The half life is 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 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 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. 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 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

conc of the reactants 0.00 log Ca vs time

molecularity of the reaction 2.00 Ca vs time

nature of reactants

temperature <0 1/Ca vs time

1/Ca vs time

>0 log Ca vs reciprocal time lof Ca vs time

Ca^2 vs time -ra = k Ca^2 Cb^4

-ra = k Ca Cb^2

-ra = k Ca

-ra = k Cb^2

Le Chatelier's principle proportional to the square of the initial conc

Hess' Law

Law of Mass Action

independent of initial conc

proportional to initial conc

Second Law of Thermo inversely proportional to initial conc

66.80

74.70

85.30

99.10

0.0021 s

100 s

231 s

768 s

45.1 min

19.6 min

19.1 min

10.4 min

3.83

7.43

8.33

9.33

25.36 m

32.5 m

52.63 m

56.23 m

0.17

0.18

0.34

0.62

257.00

275.00

300.00

527.00

Ca vs time


10

136

137

138

139

140

141

142 143

144

145

146

147

148

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 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 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. 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? When the 1st order homogeneous reaction (gasphase) 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 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 When two centrifugal pumps are connected in series, the discharge changes by a factor of When two reciprocating pumps are connected in parallel, the volumetric capacity of the system changes by a factor of The pressure drop in a pipeline changes by a factor of _____ when the velocity of the flowing fluid is doubled. Cavitation occurs in a centrifugal pump when

0.73

0.43

0.33

0.24

10.30

11.40

12.70

20.70

8150.00

9150.00

9550.00

10150.00

Cao/2m

Cao/(2m-1)

Cao/(1-2m)

Cao/2

43.10

41.30

37.10

31.80

1/8

1/16

1/32

1/64

1/2

1.00

2.00

4.00

1/2

1.00

2.00

4.00

1/2

1.00

2.00

4.00

the discharge pressure becomes too high

the discharge valve is closed

the suction pressure is too high

suction is lost

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. 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. 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.

0.63

13.10

16.90

87.20

1.05

1.22

1.72

1.89

0.60

3.58

21.00

58.30


11

149

150

151 152 153

154

155

156

157

158

159

160 161 162

163

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. When the impeller speed of an ideal centrifugal pump is doubled, the vol. flow rate of discharge is increased by a factor of The differential height between two points which a fluid has to be transferred is the The resistance of a layer of fluid to flow over the next layer is measured by 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 Specify the type of open impeller pump to use if the capacity is 400 gpm at a head of 200 ft of water. 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. If the speed of a centrifugal pump is doubled, the energy requirement becomes approximately ___ times the original energy requirement. 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. 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. The rate of evaporation at a given operating temperature in a n evaporator is more when

PhP 3300

PhP 5000

PhP 7000

PhP 12000

1/2

1.00

2.00

2exp2

potential head

pressure head

velocity head

dynamic head

viscosity

friction factor

surface tension

drag coefficient

20.00

36.00

63.00

85.00

3x2x8.5E

4x3x8.5E

4x3x6

3x2x13

95.00

134.00

248.00

320.00

2.00

4.00

8.00

10.00

32.00

55.00

77.00

94.00

15.00

20.00

25.00

30.00

when the operating pressure is high

the operating pressure is low

there is a vacuum

when the liquid level is high

An optimim number of the effects for a given application is a function of the A popular type of heat exchanger for cooling large quantities of fluid is the An evaporator is used to concentrate 10,000 lb/hr of a 20% solution of NaOH in water at 140oF using saturated steam at 25 psia at a rate of 7,000 lb/hr. The OHTC is 275 BTU/hr-ft2-oF when the pressure in the vapor is 1.7 psia. The steam economy, SE, is A cross flow heat exchanger uses mixed air at 4 kg/s that enters at 15oC and leaves at 45oC. The air cools unmixed water, which enters at 95oC and 0.70 kg/s. The OHTC equals 150 W/m2-oC. After several months of operation, a scale resistance of 0.002 m2-oC/W developed. 16. The heat transfer area required to accomplish the change is

capacity

economy

efficiency

double-pipe

plate

shell and tube

none of the given choices extended surfaces

0.82

0.86

0.89

0.92

22.2 m2

25 m2

17 m2

20 m2


12

164

165

As solution of 28% wt Na2SO4 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 120oF and cooled to 60oF using cooling water which enters at 50oF and leaves at 70oF. The crystallizer has a cooling surface of 3 ft2 per foot of length. The feed rate is 500 lb/hr and the crystallizer is seeded with 50 lb/hr of 65 mesh crystals. 19. The amount of the crystalline crop (C) produced in lb per hour is An insulator should have

166

Fouling factor

167 168

Natural convection is characterized by The Graetz number is concerned with

Reynolds number mass transfer between a gas and a liquid

Grashhoff number absorption with chemical reaction

Peclet number heat transfer in turbulent flow

Prandlt number heat transfer in laminar flow

169

Dropwise condensation occurs on

smooth clean surfaces

Dietus-Boelter equation for determination of heat transfer co-efficient is valid

contaminated cooling surfaces for fluids in turbulent flow

polished surfaces

170

clean and dirt free surfaces for liquid metals

171

fluidizing

pressure

pressure-vacuum

vacuum

0.98

0.89

0.76

0.65

305 mm

610 mm

1220 mm

2400 mm

settling ratio

screen-mesh no

reduction ratio

1.00 thickening

0.87 classification

0.70 sorting

average particle diameter 0.60 centrifugation

temperature

pressure

concentration

electric field

temperature

pressure

concentration

electric field

UMD and EMD

ordinary and Knudsen

thermal and ordinary

thermal and Knudsen

DAB = DBA

c = cA + cB

JA = JB

NA = -cDAB dxA/dz

Knudsen region

turbulent region

buffer region

viscous sub-layer

unaccomplished change Sc

relative resistance

relative time

relative position

Sh

Bi

Pe

184

A type of pneumatic conveyor system characterized by a material moving in an air stream or pressure less than ambient. 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 The estimated width of an apron conveyor having a capacity of 75 tons/hr at a speed of 50 ft/min is It is defined as the ratio of the average diameter of the feed to the average diameter of the product. The sphericity of cubical particles is 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 An ultracentrifuge is used to separate highmolecular weight fractions in polymeric or biological systems. What is the gradient for mass transfer in the separation using this mass transfer device? Ordinary diffusion takes place because of ___ driving force. What are the two limiting cases of steady-state diffusion? Which of the following is not true in (binary) equimolar counter-diffusion? 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? In unsteady-state mass transfer, the quantity (DABt/rm^2) is referred to as What is the equivalent of Prandtl number in convective mass transfer? If kx > ky, then the controlling phase is

the liquid phase

the gas phase

the interface

185

In two-phase mass transfer, equilibrium may exist

at the interface

in the gas phase

in the liquid phase

either of the bulk phases in either film

172

173 174 175 176

177

178 179 180 181

182 183

285.30

249.30

255.65

214.65

low thermal conductivity is a dimensionless quantity

high thermal conductivity does not provide a safety factor for design

less resistance to heat flow accounts for additional resistance to heat flow

a porous structure

for fluid in laminar flow

none of these

when Grashhoff number is very important


13

186 187

188

189

190 191

Which of the following processes may always be regarded as a constant- humidity process? Air conditioning in tropical countries involves

cooling of air

air conditioning

water-cooling in a cooling tower dehumidification and removal of sensible heat

heating of air

humidification by a process similar to that in a cooling tower

humidification by a process similar to airwater 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? The moisture content of a solid is given as 50% wet basis. What is the moisture content, dry basis? The moisture that can be removed by drying is called Falling-period in drying terminates at the

dry-bulb temperature

wet-bulb temperature

adiabatic saturation temperature

dew point temperature

0.50

1.00

2.00

50.00

equilibrium moisture end of constant-rate period the solute concentration of the gas is less than that of the bulk

bound moisture

free moisture

unbound moisture

origin of R vs X plot

critical free moisture content the solute concentration of the liquid and gas phase are equal

equilibrium moisture content the solute concentration of the gas is greater than the liquid

192

Which is not true at the interphase of a gas scrubbing operation?

193

He and N2 gas are contained in a conduit 5 mm in diameter and a 0.1 m long at 298 K and a uniform pressure of He at one end of the tube is 0.6 atm and 0.02 atm at the other end. Assuming equimolar countercurrent diffusion, the flux in kmol/s-m2 is 100 m3/hr of air at 60°C and 20% RH is needed for a chemical reactor. This will be obtained from process air at 60°C and 10% RH by humidifying adiabatically the process air followed by heating to its original temperature. The wattage of the heater at 80% efficiency is 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. The unit of volumetric diffusivity is If reflux to a distillation column is 100 moles/hr, when the overhead product rate is 50 moles/hr. the reflux ratio is Which of the following provides maximum contact surface for a liquid-vapour system? In extraction, as the temperature increases, the area of heterogeneity (area covered by bimodal curve) The suitable evaporator for concentration of foaming liquids is Macroscopic transfer of mass between moving fluid and surface which is of different concentration is called For a packed column the main purpose of packing is to

2.35 exp -5

2.44exp -5

1.77exp -6

1.22 exp -6

5280.00

8490.00

10050.00

11570.00

1 hr

1.6 hr

2.3 hr

2.9 hr

cm^2/sec 0.50

cm/sec 2.00

cm^3/sec 50.00

cm^2/sec^2 150.00

packed lower

bubble-cup plate column increases

sieve-plate column

wetted wall column

long tube evaporator molecular diffusion

short tube evaporator

vacuum evaporator

falling film evaporator

unsteady-state diffusion

convective mass transfer

all of these

strengthen the column

increase the surface area

increase the pressure drop in the tower

reduce the flow rate across the column

In a gas absorption operation, when the operating line crosses the equilibrium curve

the NTU is zero

the liquid flow rate is maximum

the gas flow rate is maximum

the number of stages is infinite

194

195

196 197

198 199

200 201

202

203

decreases

the solute concentration of the liquid is less than that of the bulk

dehumidification by condensing water vapor in a refrigerator

remains unchanged


14

204

0.15

0.31

0.51

0.68

0.92

0.86

0.71

0.65

14.70

18.50

20.90

22.40

0.54 min

0.85 min

0.87 min

1.18 min

208

Methanol diffuses in 0.15 cm stagnant film of 1:1 mole mixture of hydrogen and CO2 at 100oC and 2 atm. The partial pressures of methanol on both sides are 0.6 and 0.2 atm. The average diffusivity of methanol in the hydrogen and CO2 at 0 oC and 1 atm in cm2/s is Gaseous reactant A decomposes according to the reaction A --> 3R (-rA = 0.5 CA mole/L-min). The feed, which consists of 70% A and 30% inert, enters a 1.5-m3 CSTR at a flow rate of 150 L/min. 4. If CA0 = 0.30 mole/L, what is the conversion, XA? 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? 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. For Newtonian fluids, the shear stress is

constant.

inversely proportional to rate of deformation.

equal to shear rate of deformation.

a linear function of the shear rate of deformation.

209

An ideal fluid is one that is

compressible

incompressible

210

Water flows through an 8-in (ID=7.981 in) steel pipe at an average velocity of 6 ft/s. Downstream the pipe splits into an 8-in main and a 2 in (ID=2.067 in) bypass pipes. If the velocity in the bypass is twice the velocity of the main pipe, the volumetric flow rate [ft3/s] in the main pipe is An imaginary line within a fluid flow such that a tangent at any point indicates the direction of flow at that point. Air at 250C [viscosity=0.018 cP] enters a section of 2-in schedule 40 commercial steel pipe at a gauge pressure of 310 kPa and a flow rate of 1200 kg/h. Assuming isothermal flow, what is the pressure drop [kPa] in 60 m of pipe? A simple pitot tube measures

10.58

incompressible & viscous 5.29

1.84

incompressible & inviscid 0.25

stream tube

velocity profile

streamline

none of these

350.00

155.00

101.30

61.00

acoustical velocity

superficial velocity

mean linear velocity

local velocity

Which of the following meters will have the highest permanent pressure loss? In the flow meter equation, Y, indicates the

pitot tube

orifice

venturi

rotameter

mass flow rate

compressibility factor

coefficient of discharge

cross-sectional area

The loss due to sudden contraction is proportional to Stoke’s law is valid when the particle Reynolds number is Priming needed in a

velocity

turbulence

velocity head

static head

<1

>1

<5

0.00

Reciprocating pump

Gear pump

Centrifugal pump

Diaphragm pump

Maximum theoretical suction lift for water at 60˚F by a centrifugal pump is 34 ft. The same for water at 200˚F will be The most economical valve for use with large diameter pipes. Multistage compressors are used in industry because, they

40 ft

37 ft

34 ft

8 ft

butterfly

globe

needle

gate

reduce the cost of compressor

reduce the size requirement

resemble closely to isothermal compression

are easy to control

For ideally incompressible fluid, the mach number will be of the following produces maximum pressure difference for transportation of gases?

0.00

1.00

1.50

5.00

vacuum pumps

blowers

fans

compressors

205

206

207

211

212

213 214 215 216 217 218 219

220 221

222 223


15

224

The fluid property which matters for falling rain drops to acquire spherical shape is its A wastewater solution having a volume of 1000 L contains 0.21 kg phenol/m3 of solution. A total of 1.40 kg fresh granular activated carbon is added to the solution, which is then mixed thoroughly to reach equilibrium. What is the amount of phenol absorbed per kg carbon at equilibrium? The overhead product composition decreases with time in

pressure

height of descend

viscosity

surface tension

0.007 kg

0.106 kg

0.189 kg

0.198 kg

batch distillation with reflux

continuous distillation with reflux

continuous distillation without reflux

distillation operating at total reflux

low reflux ratio

small cross-section

less number of trays

high reflux ratio

228

For a binary mixture with low relativity, continuous rectification to get pure products will require Chemisorption is The stage efficiency in leaching depends on the

characterized by adsorption of heat rate of diffusion of the solute through the solid and into the liquid

an irreversible phenomenon both A and B

always in equilibrium

229

the same as van der Waals time of contact between the solid and the solution

230

Weeping in distillation or absorption column

increases tray efficiency

provides larger surface for mass transfer

results due to low gas velocity

is due to bubble cups

231

What are the two contacting phase in leaching?

extract phase and raffinate phase

solvent phase and solute phase

feed phase and solvent phase

overflow and underflow

232

Hydrogen sulfide is removed from water by contacting the solution with warm air. The operation is Disregarding the cost, which is the best solvent for the extraction of acetic acid from an aqueous solution at 25deg C? Professional Regulations Commission was created under 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. 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. Which of the following is not a requirement for utility model registration?

Distillation

Leaching

Absorption

Stripping

caproic acid

chloroform

3-heptanol

toluene

P.D. No. 223

P.D. No. 233

P.D. No. 232

P.D. No. 826

TRUE

FALSE

it depends

not governed by law

18.00

19.00

21.00

23.00

inventive step

novelty

industrial applicability

a technical solution to problem

A section of the patent application containing detailed descriptions of the benefits obtained from using the invention is called the A document issued by the DENR secretary indicating that the proposed project will cause significant negative environmental impact.

disclosure

abstract

request

claims

Environmental Impact Statement

Environmental Compliance Certificate

Environmental Impact Assessment

Environmental Critical Project

In the Philippines, sulfur for sulfuric acid manufacturing is sourced from _______ industry. Sulfur is undesirable in petroleum because

paper

cement

petroleum

detergents

it causes engine knocking

it increases the boiling pt of fuel

it poisons the catalyst in the refining process

all that are mentioned

Materials added to detergent formulation to enhance cleaning performance by exhibiting synergistic cleaning effect with surfactant. Polyethylene is an example of _____________ polymerization Principal chemical conversion in the production of resin from monomer. Carbon black is added to rubber compounding as The binder for all the powder materials of paint

fillers

brighteners

builders

perfume

condensation

addition

copolymerization

natural

condensation

hydration

polymerization

alkylation

activator pigment

curing agent vehicle

retarders opacifier

fillers filler

225

226

227

233

234 235

236

237

238

239

240 241 242

243 244 245 246

either A or B because these two mean the same thing


16

247

249 250 251

A fibrous material left after cane sugar has been milled is commonly called as Molasses is a by product of raw sugar from the ______ process Kraft process is a common name for Water insoluble cell binders of wood DDT means

252 253

Rancidity of oil can be reduced by Varnish does not contain

254

Plasticizers are added to paints to

make it corrosion resistant

make glossy surface

increase atmospheric oxidation

give elasticity and prevent cracking of the film

255

Silicone is

thermoplastic

a monomer

an inorganic polymer

thermosetting plastic

256

extrusion

mastication

vulcanization

calendering

detergent monomer 0.23

rubber synthetic rubber 0.32

pesticide polyester 0.68

polyester pigment 0.77

260

The process involved in converting rubber into a thin sheet or coating it on fabric is called Alkyl benzene sulfonate (ABS) is a Neoprene is a Steam enters an adiabatic turbine at 10 MPa and 500 degC at a rate of 3 kg/s and leaves at 0.1 MPa. If the power output of the turbine is 2 MW, determine the turbine efficiency. Work is a

path function

state function

261

Throttling process is

property of the system a reversible and isothermal process

an irreversible and constant entropy

a reversible and constant entropy process

state description of a system constant enthalpy process

262

A sample consisting of 1.00 mole of Argon gas is expanded isothermally and reversibly at 0°C from 22.4L to 44.8L. The heat absorbed by the system is Maximum work can be obtained from a system when the change taking place in it is The ratio of work performed by a system and the heat it absorbed from a reservoir is referred to According to the first law of thermodynamics

0.00

+1.13 kJ

+1.57 kJ

+2.27 kJ

isothermal

adiabatic

reversible

irreversible

Entropy

Gibb’s free energy

carnot efficiency

Energy is neither lost nor gained in any energy transformation.

Perpetual motion is possible.

Energy is conserved in quality but not in quantity.

Helmholtz free energy Energy is being created as time passes. We have more energy in the universe now than when time began.

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 In choosing the refrigerant, the fluid must have the following characteristics, except

greater than 0.85

in between 0.75 and 0.85

less than 0.75

in between 0.84 and 0.90

environmentally benign

has a vapor pressure less than atmospheric

must be economically viable

exist at a high pressure at the condensation temperature

Coolers and boilers are ordinarily operated at ________ condition. For an isolated system, maximum entropy will occur at A carnot cycle consists of

isobaric

isenthalpic

isothermal

isentropic

half-life

critical condition

equilibrium

start of the process

two isothermal and two adiabatic process

two isochoric and two adiabatic process

one isochoric, one isobaric, and two adiabatic process

one isothermal, one isochoric and two adiabatic process

This is also known as the volume fraction of the voids in packed beds.

sphericity

porosity

superficial velocity

specific volume

248

257 258 259

263 264 265

266

267

268 269 270

271

bagasse

pulp

cellulose

waste

milling

extraction

evaporation

crystallization

sulfate pulping pulp Diphenyldichlorotrip henylethane decoloration pigment

sulfite pulping cellulose dichlorodiphenyldichlo roethane hydrogenation dryer

bleaching xylem Dichlorodiphenyldichlor obutane oxidation thinner

calendering lignin diphenyldichlorotriph enylbutane purification anti-skinning agent


17

272 273

274

275 276

277 278

279

280

281

282

283

284

A measure of the ratio of the drag force acting on a unit area of the impeller & the inertial stress. 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. The equation del(P) = -(rho)(g) del(z) is known as the hydrostatic vertical law for which all the following assumptions are applied, except

Froude number

Reynold’s number

Mach number

Power number

3.00

2.00

0.20

0.12

shear forces are not involved

fluid is incompressible

z axis is defined vertical & downward in direction

normal surface forces & gravity are the only forces involved

Which of the following can be adjusted by human operator in a closed feedback control loop? 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. Dead time is a function of distance and 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? The parameter which completely describes the behavior of the response to a disturbance of a second order system is the 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? 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 The equivalent diameter of a concentric annular space where 1-inch OD pipe is located inside a 2inch ID pipe is 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%. The BPR of a 50% NaOH solution at an evaporator pressure of 4.7 psia is

set point

controller output

process variable

load variable

current

temperature

emf

resistance

momentum 2.83kPa/K

acceleration 0.35kPa/K

time 17kPa/K

velocity 0.06kPa/K

Time constant

damping coefficient

Rise time

overshoot

11.61 ft/s

37.1 kg/s

37.1 lb/s

317 lb/s

9365.00

9461.00

52581.00

393308.00

pi/4 inch

1 inch

1.5 inch

2 inches

20.20

41.40

50.50

58.60

73 degF

173 degF

233 degF

297 degF


18

ANSWERS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

A C D D B C C C D C D C C C C A B B D B C D B D D C B B B C C B B A C B B C B A A A B B C C A D B C

51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100

C A B B A C C B C D C D B A A C A C D A B A B D C B C A B A D C C D A D B A C B D A C C A D D B B B

101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150

A B A B C a C A C A B C A B B A C C D C D C A A B B C D D C B C C A A C A B B D C C B D C C B B B C

151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200

A A B A C C C B B B C B D B A C B D C C D B C C A A B B A C D C A B A D C B B C D A A D B C B A A A

201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250

C B D C C B B D D C C D D B B C A C B A C B D D B A D C C C D D C A A C A D B A A C B D A A C C B D

251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284

C B A D C D A B C B D C C C A B D A C A B D B C A C D C B C A B B A


19

Chemical Engineering Review Questions[1]

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