Concepts Flashcards
1
Q
(Design) It is the ability to resist deformation or deflection . A. Strength B. Stiffness C. Toughness D. Hardness
A
B. Stiffness
2
Q
(Instrumentation) He suggested that pressure sensors may be divided into four categories, namely, utility, general industry, process control and precision and test. A. Pascal B. Toricelli C. Saunders D. Bourdon
A
C. Saunders
3
Q
(Distillation) For a non-azeotropic solution being distilled, the temperature in the distillation column, from bottom to top\_\_\_\_\_. A. Increases B. Decreases C. Becomes Maximum D. Becomes constant
A
B. Decreases
4
Q
(Distillation) Compounds that form an azeotrope may be separated through distillation by\_\_\_\_ A. adding a separating agent B. increasing the temperature C. increasing the pressure D. A and C
A
D
5
Q
(Thermodynamics) Which of the following has the highest entropy at a certain condition? A. Dichloromethane B. Moist Air C. Ice D. Water Vapor
A
B. Moist Air
Gas = higher entropy
mixture = higher entropy
6
Q
(CheCal) It is an improvement in power loss by another device thus it is mostly used in cases where there are very large flow rates. A. manometer B. rotameter C. turbine meter D. venturi meter
A
D. Venturi Meter
7
Q
(Diffusion) Diffusion that takes place in fluid phases by physical mixing and by eddies of turbulent flow. A. Eddy diffusion B. Forced Diffusion C. Thermal Diffusion D. Reversed Diffusion
A
A. Eddy Diffusion
8
Q
- Which of the following is false?
A. diffusion occurs in at least one phase of many mass transfer operations
B.one valid assumption in steady state diffusion is that concentration at any point changes with time as the process proceeds
C. the theory of diffusion is assumed in the direction perpendicular to the interface despite the random movement of molecules in all directions
d. Fick’s law states that the diffusion flux J_a is proportional to the concentration gradient dca/db using the diffusivity of the component A and its mixture with component B
A
B
9
Q
(Diffusion)
which of the following is a valid type of diffusion?
A. only one component of the mixture is transferred to and from the interface and the flow is the same of the flow of the particular component
B. the diffusion of one component in a mixture is balanced by an equal and opposite molar flow of another component,thus, there is no molar net flow
C. two components diffuse in different directions but the molar flows are unequal
D. all of the above
A
D.
“ A is one way diffusion letter, b is equimolar counter diffusion and c is uneven counter diffusion”
10
Q
(Diffusion) the ratio of the convective mass transfer rate to the diffusion rate A. Sherwood B. Prandtl C. Nusselt D. Schmidt
A
A.
11
Q
(Diffusion) for laminar flow the reynolds analogy is exact if A. pressure gradient = 0 B. schmidt number = 1 C. Prandtl number = 1 D. all of the above
A
D.
12
Q
(Diffusivity) When a drop of blue liquid is added to a cup of water then mixed using a spoon what type of mass transfer or occurs? A. molecular diffusion B convective mass transfer C. thermal diffusion D. both a and b
A
D.
13
Q
(ChE Thermo) which of the following cycles has two isobaric steps A. otto B. diesel C. stirling D. ericsson
A
D. Ericsson
14
Q
(ChE Thermo) which of the following cycles has no isentropic steps A. carnot B. diesel C. brayton D. stirling
A
D. Stirling
15
Q
(ChE Thermo) which of the following has higher isentropic work than the actual ? A. turbine B. pump C. compressor D. condenser
A
A. Turbine
16
Q
(ChE Thermo) which of the following ideal gases has the highest value of γ A. methanol B. nitrogen C. neon D. water vapor
A
C. Neon (monoatomic)
17
Q
(ChE Thermo)
which of the following is false about a bomb calorimeter
A. the heat is equivalent to enthalpy
B. it operates at isochoric condition
C. it can withstand combustion reactions D. all of the statements are true
A
A.
It should be delta U
18
Q
(ChE Thermo)
which has the largest numerical value for a work due to expansion at a constant temperature?
A. free expansion
B. expansion against a constant pressure P_2
C. reversible expansion going to a pressure P_2
D. all have equal value for work
A
C
19
Q
(ChE Thermo)
which of the following is false about the change in enthalpy of a gas at isobaric condition?
A. the value is positive if internal energy is positive and if the volume is increased
B. the value is positive if internal energy is positive and if the temperature is increased
C. the value is negative if internal energy is negative and if the volume is decreased at high p
D. all statements are true
A
D
ΔH=ΔU+PΔV
A. (+)= (+)+(+)(+) correct
B. (+)= (+)+(+)(+) correct
C. (-)= (-)+(+high)(-) correct
20
Q
(ChE Thermo)
which of the following is true about complete combustion of methane?
A. it requires -890 kilojoules of heat to burn completely and to produce water vapor
B. for every mole of methane, 2 moles of water vapor are consumed
C. a heat value of 445.15 kilojoules is released accompanying the formation of two moles of O2
D. none of the above
A
D
21
Q
(ChE Thermo) in coffee cup calorimetry where the heat of solution is obtained what is the system? A. the solution formed B. the dissolution process C. the reacted salts D. all of the above
A
B
22
Q
(Diffusion)the enrichment of ethyl alcohol in the vapor phase from an aqueous ethyl alcohol solution during rectification is an example of
a. unicomponent diffusion
b. equimolal counter diffusion
c. phase drift
d. convective diffusion
A
B. Equimolal counter diffusion
23
Q
(Diffusion)the diffusivity of a binary system as given in the equation of Fick’s law is usually measured relative to the
a. stationary observer
b. velocity of the earth as it rotates around the sun
c. mass-mean velocity of component A
d. volume-mean velocity of components B and A
A
D.
24
Q
(Diffusion)the diffusivity of component A relative to itself, that is D_AA
a. has no physical meaning
b. has a physical meaning but cannot be measured
c. has a physical meaning and can be measured
d. is beyond comprehension
A
C
25
(Diffusion)the reynolds analogy is applied when
a. the reynolds numbers less than 2,100
b. the Prandtl number is unity
c. the prandtl number is not equal to 1
d. no mass transfer is involved
B
26
(Diffusion)the molar flux of component A in molecular diffusion is independent of
a. mass transfer area
b. concentration gradient
c. total pressure
d. temperature
A
27
(Diffusion)a dimensionless number that represents the ratio of the mass transfer by the molecular diffusion to the total mass transfer is
a. sherwood number
b. reynolds number
c. schmidt number
d. none of these
D.
28
(Diffusion)the molar diffusion flux of A relative to a stationary plane is a combination of
a. N_a + N_ b + molecular diffusion
b. fick's law of diffusion and diffusivity
c. phase drift + molecular diffusion
d. bulk diffusion and pressure diffusion
C.phase drift is also convective flux
29
(Diffusion)the fick's law of diffusion gives the rate of diffusion based on
a. pressure driving force
b. temperature driving force
c. concentration driving force
d. all of these
C.
30
(Diffusion)equimolar counter-diffusion means that the
a. bulk in terms of mass is not moving
b. concentration driving force is zero
c. convective flux is very high
d. bulk in terms of moles is not moving
D.
31
(Diffusion)for a gas phase diffusion, unicomponent diffusion through a gas-liquid interface will likely occur if
a. one component is soluble and the other is not
b. both components are soluble in the solvent
c. both components are insoluble in the solvent
d. none of these
A
32
(Diffusion)the rate of mass transfer of component A through an interface in a turbulent flow system is less affected by
a. concentration of gradient A
b. mass transfer area
c. thickness of the laminar film adjacent into the interface
d. the flow rate of gas and liquid
D
33
(Diffusion)for binary unicomponent diffusion, the concentration profile of the diffusing component along the diffusion path is
a. linear
b. quadratic
c. logarithmic
d. none of these
C
34
(Diffusion)the transport analogy among mass, heat and momentum transfer is complete when
a. the temperature gradient and concentration gradient are equal
b. no convective flux or phase drift is involved
c. the resistance to mass and heat transfer are negligible
d. the momentum transfer rate is negligible
B
35
(Diffusion)a wetted wall column is usually used to determine mass transfer coefficient experimentally because
a. the mass transfer area can be measured accurately
b. the concentration gradient can be measured accurately
c. there is no better device to use
d. it is an inexpensive piece of equipment
A
36
(Diffusion)it provides the basis for the quantitative description of the diffusional phenomena of molecules
a. stokes-einstein postulation
b. kinetic theory of gases
c. thermal diffusion
d. potential theory
B
37
(Diffusion)the method of solute transfer which involves rapid movement of large chunks of fluid in turbulent motions
a. molecular diffusion
b. eddy diffusion
c. thermal diffusion
d. kinetic transport
B
38
(Diffusion)ammonia (A) being absorbed from air(B) into water is an example of
A. steady state equimolar diffusion
B. steady state unicomponent diffusion
c. steady state diffusion in multicomponent mixtures
d. unsteady-state equimolal diffusion
B
39
(Diffusion)In steady-state equimolal counter diffusion, the following are true :
a. N_ b = 0; N_a constant
b. N_a = - N_b; N_a + N_b = 0
c. N_a = 0; N_ b is non-zero
d. N_a + N_b = constant
B
40
(Diffusion)the flux of A in uni component diffusion is different from that of equimolal counter diffusion because of
a. the molecular diffusion of A relative to a fixed point
b. the bulk motion of the phase
c. the concentration gradient of B is zero
d. the flux of A relative to the average molar velocity
B
41
(Diffusion)it represents the total mass transfer to mass transferred by molecular diffusion
a. sherwood number
b. schmidt number
c. reynolds number
d. nusselt number
A
42
(Diffusion)it is a measure of the diffusive mobility of individual molecules in solution
a. eddy diffusivity
b. diffusion coefficient
c. mass transfer coefficient
d. thermal diffusion
B
43
(Diffusion)based on the penetration theory the MTC will increase/ decrease by a factor of ____ if the contact time of the diffusing faces is tripled
a. 0.42
b. 0.21
c. 1.62
d. 0.5773
Dk_c = 2sqrt(D_v/(pi)(time))
44
```
(ChE Thermo)
it is defined as the fraction 1/273.16 of the temperature of the triple point of water
A. celsius
B. fahrenheit
C. kelvin
D. rankine
```
C
45
```
(ChE Thermo)
the amount of heat absorbed when CO2 gas reacts with the solid CaO to form solid CaCO3 is measured in a bomb calorimeter. the data obtained give a direct measure of
A. ΔU
B. VΔP
C. ΔH
D. Cp
```
A
46
```
(ChE Thermo)
a refrigerant whose molecular formula is CBrF2CBrF2 is labeled as
A. R-114
B. R-114a
C. R-114B2
D. R-1142B
```
C
47
```
a unit operation wherein specific components of a fluid phase (gas or liquid) are preferentially adhered to the surfaces of the solid
A. adsorption
B. absorption
C. chemisorption
D. leaching
```
A.
48
```
(Adsorption)
the adsorbent used in the purification of hydrocarbon products
A. alumina
B.bone char
C. fuller's earth
D. silica gel
```
D
49
```
(Adsorption)
the component adsorbed in adsorption operation is called
A. adsorbate
B. adsorbent
C. adsorbed materials
D. chemisorption
```
A
50
```
(Adsorption)
a type of adsorption which results in intermolecular forces of attraction between molecules of the solid and the substance adsorbed.
A. gas phase adsorption
B. liquid phase adsorption
C. physical adsorption
D. chemical adsorption
```
C
51
```
(Adsorption)
physical adsorption is
A. an irreversible phenomenon
B. a reversible phenomenon
c. accompanied by evolution of heat
d. both b and c
```
D
52
```
(Adsorption)
chemisorption (chemical adsorption) is A. the same as van der waals adsorption
B. characterized by adsorption of heat
C. also called activated adsorption
d. none of these
```
C
53
```
(Adsorption)
which of the following adsorbents is used to decolorize yellow glycerin
A. silica gel
B. alumina
C. fuller's earth
D. activated carbon
```
D.
54
(Adsorption)
freundlich equation applies to adsorption of solute from
A. dilute solutions over a small concentration range
B. gaseous solutions at high pressure
C. concentrated solutions
D. none of these
A
55
(Adsorption)
in case of physical adsorption the difference between heat of adsorption and heat of normal condensation is
A. equal to the heat of formation of surface compound
B. equal to the heat of wetting
C. 0
D. called integral heat of adsorption
B
56
(Adsorption)
pick out the wrong statement
Generally for physical adsorption, a gas of
A. higher molecular weight is adsorbed in preference to a gas of low-molecular-weight
B. high critical temperature is adsorbed in reference to a gas of low critical temperature
C. low volatility is adsorbed in preference to a gas of high volatility
D. both b and c
D
57
```
(Adsorption)
the change in enthalpy per unit of adsorbed gas when adsorbed on a gas-free or outgassed adsorbent to form a definite concentration of adsorbate is called its
A. integral heat of adsorption
B. Heat of wetting
C. differential heat of adsorption
D. heat of normal condensation
```
A
| keyword is definite concentration
58
(Adsorption)
with an increase in concentration of the adsorbate the integral heat of adsorption
A. increases
B. decreases
C. remains unchanged
D. may increase or decrease depends on type of adsorbate
B
59
```
(Adsorption)
the change in enthalpy when a unit quantity of gas is adsorbed by a relatively large quantity of adsorbent (on which a definite concentration of the adsorbed gas already exists is termed as)
A. the differential heat of adsorption
b. heat of wetting
C. integral heat of adsorption
d. heat of normal condensation
```
A
| keywords are "change in enthalpy"
60
```
(Adsorption)
as complete saturation of an adsorbent is approached the differential heat of adsorption approaches
A. heat of normal condensation
B. integral heat of adsorption
C. 0
d. none of these
```
A
61
```
Ion-exchange process is similar to
A. absorption
b. extraction
c. adsorption
d. leaching
```
C
62
```
(Adsorption)
CO2 can be adsorbed by
A. hot cupric oxide
B. cold calcium hydroxide
C. adsorption
D. heated charcoal
```
D
63
(Leaching)
| when an undesirable component is removed from a solid with water the leaching process is called
washing
64
(Leaching)
copper salts are dissolved or leached from ground ores by _____ while cobalt and nickel salts are leached from their ores by ______
sulfuric acid or ammoniacal solutions
sulfuric acid-ammonia-oxygen mixtures
65
(Leaching)
gold this leached from its ore using an ________ and sodium hydroxide is leached from a slurry of calcium carbonate and sodium hydroxide prepared by reacting Na2CO3 with _____
aqueous sodium cyanide solution
-
calcium hydroxide
66
```
(Leaching)
at equilibrium the concentration of the liquid retained by the solid leaving any stage is ____ the concentration of the liquid overflow from the same stage.
A. higher than
B. the same as
C. lower than
D. has no relationship to
```
B
67
(Leaching)
The underflow in leaching is consisting of
A. the inert solid and the retained solution
B. the solvent and the dissolved solute
C. the solution which is not retained by the inert solid
D. the inert solid
A
68
(Leaching)
the rate-determining step in leaching is
A. the dissolution of solute in solvent
B. the diffusion of solvent into the solid particles
C. the diffusion of solute towards the surface of the solid
D. the diffusion of solute from the surface towards the bulk of the solvent
C
69
(Leaching)
the overflow in leaching is consisting of
A. the inert solid and the retained solution
B. the solvent and the dissolved solute
C. the solution which is not retained by the inert solid
D. the inert solid
C
70
```
(Leaching)
the N value for overflow is generally
A. less than one
B. greater than 1
C. equal to 1
D. equal to zero
```
D
71
(Leaching)
all of the following are assumptions in ideal leaching except which of the following?
A. the inert solid is not dissolved in the solvent
B. sufficient contact time is provided so that all solute is dissolved in the solvent
C. the concentration of solution in the final stage is equal to the concentration of solution in the initial stage
D. the solute is infinitely soluble in solvent
C
72
```
(Leaching)
this leaching equipment is generally associated with the slowly rotating rake at the bottom of container
A. thickener
B. hilderbrandt extractor
C. fixed-bed leaching
D. bollman extractor
```
A
73
```
(Gas Abs)
What is the pure solvent or dilute solution that is distributed over the top of the tower called?
A. rich gas
B. strong liquor
C. lean gas
D. weak liquor
```
D
74
(Gas Abs)
In packed column gas absorption, a transfer unit means that
A. a mole of solute is transferred in a unit height
B. the mass transfer coefficient will approach unity
C. the average driving force is equal to unity
D. low concentration range is equal to the average driving force
D
75
```
(Gas Abs)
in gas absorption the use of liquid flow rate far above the minimum value will result in
A. infinite number of plates
B. fewer number of plates
C. more number of plates
D. none of these
```
B
76
```
(Gas Abs)
at this point the entire column is filled with liquid and the gas now has to bubble through the liquid in the packing voids
A. flooding-point
B. loading point
C. flooding velocity
D. mass velocity
```
A
77
```
(Gas Abs)
in a gas absorption packed tower the most economical gas velocity is considered to be _____ the flooding velocity
A. equal to
B. about half
C. twice
D. greater than
```
B
78
```
(Gas Abs)
in a gas absorption column the pressure of the lean gas is expected to be ____ the pressure of the rich gas entering the column
A. lower than
B. higher than
C. the same as
D. double
```
A
79
```
(Gas Abs)
which tray type is the cheapest and lowest pressure drop
A. sieve tray
B. bubble cap tray
C. Valve tray
D. packed column
```
A
80
```
(Gas Abs)
for moderately soluble gases with relatively little interaction between the gas and liquid molecules which law applies most to establish equilibrium relationship?
A. Raoult's Law
B. Henry's Law
C. Dalton's Law
D. None of these
```
B
81
(Gas Abs)
in the choice of a solvent for gas absorption one of the properties to be considered is
A. solvent should have a low vapor pressure
B. solvent should have low boiling point
C. solvent should be highly viscous
D. solvent should be less expensive
A.
82
(Gas Abs)
in the case of a straight or concave downward operating line and the straight or concave upward equilibrium line, the minimum liquid rate is that at which
A. the operating line just touches the equilibrium line at the bottom of the tower
B. the operating line just touches the equilibrium line on top of the tower
C. operating line intersects the equilibrium line at the middle of the tower
D. the slope to the operating line is smaller than the equilibrium line
A
83
(Gas Abs)
when dilute solutions are involved in gas absorption one of the following is not applicable
A. henry's law
B. H_L=V/S(k_y)a
C. equilibrium and operating lines are straight
D. N_G= Δy/(Δy)_LM may be used
B
84
(Gas Abs)
in gas absorption, packings are used
A. to reinforce the absorption tower due to drag created by the liquid and gas
B. to disseminate the heat generated to maintain isothermal conditions
C. to increase the area of contact between the gas in the liquid
D. to reduce the pressure drop created by the flowing gas
C
85
(Gas Abs)
when the liquid flow rate is fixed and the composition of the liquid and gas at the bottom of the absorption tower or fixed the limiting flow rate to give infinitely tall tower becomes
A. the maximum flooding velocity of the vapour
B. the minimum loading velocity of the liquid
C. the maximum flow rate of the vapor
D. the minimum flow rate of the vapor
D
86
(Gas Abs)
the rate equation in terms of the gas-phase mass transfer coefficient is used in design calculations instead of that in terms of the liquid phase when
A. the solubility of the solute in the solvent is very low
B. the controlling resistance is that of the liquid phase
C. the controlling resistance is that of the gas phase
D. the tie line is horizontal
C
87
(Gas Abs)
it is not very necessary to correct the rate equation for the phase drift encountered during gas absorption since the height calculated will be
A.slightly over designed anyway
B. slightly under designed anyway
C. based on equimolal counter diffusion anyway
D. based on the same percentage recovery anyway
A
88
(Gas Abs)
the overall height of a transfer unit based on the gas phase will equal the gas phase individual HTU, Hy when
A. the equilibrium curve is linear
B. the operating line is linear
C. the gas phase resistance is very small compared with the liquid phase
D. the liquid phase resistance is very small compared with the gas phase
D.
89
```
(Gas Abs)
assuming that the penetration theory applies in an interfacial mass transfer contact, the liquid phase mass transfer coefficient will increase by a factor of _______ if the diffusivity of the solute becomes twice and the contact time becomes 1/2.
A. 2
B. 1
C. 1/2
D. 4
```
A
(Penetration theory)
k=1.13√(Dv/t)
90
```
(Gas Abs)
in a stripping or desorption operation the equilibrium curve is
A. above the operating line
B. below the operating line
C. perpendicular with the tieline
D.linear
```
A
91
```
(Gas Abs)
Co-current gas - liquid up flow contacting device is highly characterized by
A. low gas-liquid interaction regime
B. dispersed bubble flow regime
C. liquid rich and gas richh regime
D. pulsing flow regime
```
B
92
(Gas Abs)
pressure drop is one of the most important parameters in the design of two phase co-current bed because
a. pumping cost could be a significant portion of the total operating costs
B. it may help characterize the hydrodynamics of the system
C. it may affect the retention of the liquid in the packed bed
D. all of these
D
93
```
(Gas Abs)
flooding condition is the only consideration that dictates the minimum column diameter that can be used for a specified gas absorption in a packed column
A. true
B. false
C. cannot be determined
```
B
94
(Gas Abs)
in gas absorption if the concentration are expressed in mole ratio, that is, moles of solute per mole of solute free medium it is necessary to assume that the operating line is straight when the coordinates are x and y
A. true
B. false
B
95
(Gas Abs)
in packed columns the pressure drop for irrigated packings is always greater than the pressure drop for dry packings because
A. the surface of dry packing is smoother
B. the flow area of dry packing is greater C. the drag friction is lesser than the skin friction for dry packing
D. none of these
B
96
```
(Gas Abs)
the mechanism of mass transfer in a gas absorber is best described by
A. penetration theory
B. two film theory
C. chilton colburn analogy
D. surface renewal theory
```
B
97
(Gas Abs)
a wetted wall column is usually preferred over a packed column to determine mass transfer coefficient experimentally because for a wetted wall column ____ can easily be measured
A. the concentration gradient of A
B. the mass transfer area
C. the thickness of the laminar films adjacent to the interface
D. the flow rate of gas and liquid
B
98
```
(Gas Abs)
in gas absorption, when the conditions at the bottom of the tower are fixed and the gas flow rate is given if the limiting flow rate based on equilibrium conditions that will require infinitely tall tower is
A. minimum liquid flow rate
B. maximum liquid flow rate
C. minimum gas flow rate
D. maximum gas flow rate
```
B
99
```
(Gas Abs)
when the gas flow rate induces flooding in a packed column gas absorber this is best remedied if the percent recovery of the solute is to be maintained by
A. reducing the liquid flow rate
B. reducing the vapor flow rate
C. increasing the diameter of the column
D. increasing the height of the column
```
C
100
(Gas Abs)
when the two film theory is applied to gas absorption, the overall resistance can be expressed in terms of the individual resistances in the form 1/Kya=1/kya + m/kxa. this is possible because of one important assumption. this assumption is
A. the operating line is linear
B. the line has a slope between 0 and 1
C. the slope of the equilibrium curve near the tie line is linear
D. the solute forms an ideal solution with the solvent
C
101
(Gas Abs)
in a gas absorption tower mass transfer occurs primarily
A. from the liquid phase to the gas phase
B. from the liquid phase to the packing
C. from the gas phase to the liquid phase D. from the gas phase to the packing
C
102
```
it is a unit operation within which involves the mass transfer of soluble materials from the solid phase to the liquid phase
A. absorption
B. leaching
C. desorption
D. humidification
```
B
103
(Gas Abs)
the pressure drop along a packed tower is
A. inversely proportional to the mass flow rate
B. inversely proportional to the square of the mass flow rate
C. directly proportional to the mass flow rate
D. directly proportional to the square of the mass flow rate
D
104
```
the method of separating a particular gaseous component from a mixture of gases due to their differences in solubility in a liquid phase is
A. adsorption
B. extraction
C. absorption
D. distillation
```
C
105
```
(Gas Abs)
the mass transfer rate of a material from one place to another across an interface is increased by ____ the difference between the bulk concentration of and the concentration at the interface between two phases
A. Increasing
B. Decreasing
C. Keeping constant
D. making zero
```
A
106
```
(Instru)
it can result in the instrument giving erroneous readings as influenced by any physical obstruction, wear-and-tear or electrical fields.
A. disturbance
B. signal
C. waveform
D. noise
```
D
107
```
(Instru)
it is a feature that prevents a machine from harming the operator or itself by making the state of two mechanisms mutual dependent to each other
A. alarm
B. magnet
C. interlock
D. safety switch
```
C
108
```
(Instru)
another name for the Yamatake system
A.SCADA
B. android
C. microsoft
D. azbil
```
D
109
```
(Instru)
it is a set of procedures that must be done to prevent accidental start-up of machines or equipment during maintenance or servicing activities
A. machine guarding
B. interlock system
C lockout tagout
D protective equipment
```
C
110
```
(Instru)
it accounts for the difference between successive measured values under a single process condition
A. reproducibility
B. repeatability
C. accuracy
D. precision
```
D
111
```
(Instru)
he suggested that pressure sensors may be divided into four categories namely: utility, general industry, process control and precision and test
A. pascal
B. toricelli
C. saunders
D. bourdon
```
C
112
```
(Instru)
it is a system of software and hardware elements known in the industry that allows control of industrial processes either locally or at remote locations, monitoring, gathering and processing real-time data direct interactions with devices through HMI and records events into a log file.
A. PLC
B. SCADA
C. DCS
D. SAP
```
B
113
```
(Instru)
a PI controller of a first-order process is subjected to a unit step input. if the integral constant is fixed, increasing the proportional gain will
A. increase the overshoot
B. increase the oscillation
C. decrease the offset
D. decrease the overshoot
```
D
114
```
(Instru)
a PID control process has a highly oscillating response. the process can be stabilized by
A. increasing proportional gain
B. decreasing proportional gain
C. increasing derivative time constant
D. decreasing derivative time constant
```
B
115
```
(Instru)
the integral of a dirac function is a
A. ramp function
B. step function
C. impulse function
D. pulse function
```
B
116
```
(Instru)
in the control of pressure in a distillation column there is no need to include
A. proportional control
B. integral control
C. derivative control
D. automatic control
```
C
117
```
(Instru)
a spring motion is described by the differential equation x''(t) + 5x(t) + 6x(t) = 0. the motion of the spring is
A. overdamped
B. underdamped
C. critically damped
D. undamped
```
A
118
```
(Instru)
a PI controller of a first order process is subjected to a unit step input. if the integral constant is fixed decreasing the proportional gain will
A. increase the overshoot
B. increase the oscillation
C. decrease the overshoot
D. decrease the offset
```
A
119
```
(Instru)
if a step function is applied to the input of a processes system and the output is of the form Y=e^t sint the system is
A. stable
B. unstable
C. cannot be determined
```
B
120
```
(Instru)
The range of value for K for a system with characteristic equation given by s^4+6s^3+11s^2+6s + K=0 is
A. K>0
B. K<10
C. K>10
D. 0
```
D
121
```
(Instru)
is the system with the transfer function
Y(s) = (s-1)/(s+2)(s^2+4) stable or unstable?
A. stable
B. unstable
C. cannot be determined
```
A
| denominator has higher degree
122
```
(Instru)
a control system in which the control action is somehow dependent on the output
A. closed loop system
B. open loop system
C. feedforward control system
D. deadtime compensator
```
A
123
```
(Instru)
a property of a closed loop system which permits the output (or some other controlled variable) to be compared with the input of the system (or input to some other internal is situated component or subsystem) so that the appropriate control action may be formed as some fraction of the output and input
A. feedback control system
B. control system
C.continuous-time
D. bandwidth
```
A
124
```
(Instru)
a frequency response measure of how well the system response to variations in input signal
A. feedback
B. control system
C. continuous time
D. bandwidth
```
D
125
```
(Instru)
a signal defined at or of interest at only discrete (distinct) instance of the variable (upon which it depends)
A. analog signal
B. continuum time signal
C. a digital signal
D. sos signal
```
C
126
```
(Instru)
a device that converts an analog or continuous signal to a discrete or digital signal
A. analog to digital a/d converter
B. digital to analog d/a device
C. pressure to voltage converter
D. discrete to continuous converter
```
A
127
```
(Instru)
it is used to convert one signal or energy form into another
A. transducer
B. amplifier
C. detector
D. resistor
```
A
128
```
(Instru)
the part of the deviation of the response which approaches zero as time approaches infinity
A. steady state response
B. output
C. transient response
D. frequency response
```
A
129
```
(Instru)
the integral of a unit step function is also known as
A. unit ramp function
B. sinusoidal function
C. unit impulse function
D. transcendental function
```
A
130
(Instru)
when the total number of variables in a process is greater than the number of independent equations that can be set up the process is said to be
A. over specified
B. under specified
C. the degrees of freedom is 0
D. the degrees of freedom is less than zero
B
131
```
(Instru)
a control structure with two feedback controllers with the output of the primary controller changing the segments of the secondary controller whose output goes to the final controller
A. feedforward control
B. ratio control
C. cascade control
D. override control
```
C
132
```
(Instru)
a type of advanced control system that identifies continuously online the parameters of the process as they change and returns the controller appropriately
A. linear control
B. adaptive control
C. cascade control
D. override control
```
B
133
```
(Instru)
a sensor usually made of a semiconductor that utilizes the effect of temperature on the resistance to current is called a
A. thermocouple
B. thermistor
C. resistor
D. capacitor
```
B
134
```
(Instru)
given the characteristic equation of a closed loop transfer function,
2s^3 + 4s^2+4s+12=0
the system is
A. stable
B. unstable
C. cannot be determined
```
B
| negative roots or negative parts or real root.
135
(Instru)
consider the characteristic equation of a certain closed loop control system
s^3 + 3s^2 + (K+2)s + 4 = 0
the range of k so that the system is stable is
A. K is greater than -2.75 but less than 0.528
B. K is greater than 0.528
C. K is less than -2.75
D. none of these
B
| Solve for roots using calc
136
```
(Instru)
a system has poles at -1, -5 and zeroes at 1 and - 2. is the system stable or not?
A. stable
B. unstable
C. cannot be determined
```
A
zeroes are roots of numerator
poles are roots of denominator
numerator is not greater than denominator, so stable
137
(Instru)
if a step function is applied to the input of a system and the output is of the form Y=t is the system stable or unstable?
Unstable
138
(Instru)
if a step function is applied to the input of a system and the output remains below a certain level for all time is the system necessarily stable?
false
139
```
(Flotation)
which flotation stage alters the physico-chemical properties of the particles
A. conditioning
B. scavenger
C. separation
D. frothing
```
A
140
```
(Flotation)
what types of particles would flow to the surface during flotation
A. porous
B. hydrophilic
C. hydrophobic
D. nonporous
```
C
141
```
(Flotation)
flotation depends on the _____ of the solid particles
A. bulk density
B. diameter
C. true density
D. wettability
```
D
142
```
(Flotation)
it enables the particles to adsorb collectors
A. dispersants
B. activators
C. flocculants
D. frothers
```
B
143
```
(Flotation)
it promotes aggregation to improve sedimentation
A. dispersants
B. activators
C. flocculants
D. frothers
```
C
144
```
(Flotation)
which of the following does not involve flotation
A. salt water purification
B. paper pulp deinking
C. KCl and NaCl separation
D. wheat hull and kernel separation
```
A
145
```
(Flotation)
it is the flotation cell that purifies the rougher overflow
A. scavenger
B. cleaner
C. conditioner
D. rougher
```
B
146
```
any operation in which one solid is separated from another by floating one of them at or on the surface of a fluid
A. coagulation
B. flotation
C. centrifugation
D. sedimentation
```
B
147
```
(Flotation)
the flotation agent that prevents coalescence of air bubbles as they travel to the surface of the water is/are
A. collectors
B. promoters
C. frothing agent
D. modifying agent
```
C
148
```
(Flotation)
a flotation modifier which assists in the selectivity (sharpness of separation) or stop unwanted minerals from floating
A. depressants
B. activators
C. alkalinity regulators
D. promoters
```
A
149
```
(Flotation)
dispersants are important for the control of slimes which sometimes intervene with the selectivity and increase reagent consumption. another term for dispersant is
A. deflocculant
B. depressants
C. frothers
D. regulators
```
A
150
```
(Flotation)
an example of a collector for flotation of metallic sulphides and native metals is
A. xanthates
B. sodium silicate
C. sodium sulfide
D. sphalerite
```
A
151
```
(Flotation)
which of the following is an example of a deflocculant
A. sulfuric acid
B. lignin sulforate
C. dithiophosphate
D. molybderite
```
B
152
```
(Flotation)
froth flotation is most suitable for treating
A. iron ores
B. sulfide ores
C. quartz
D. metal ores
```
C
153
```
(Flotation)
in froth flotation the chemical agent added to cause air adherence is called
A. collector
B. frother
C. modifier
D. promoter
```
A
154
```
(Flotation)
pine oil used in a flotation process acts as a
A. collector
B. modifier
C. frother
D. activator
```
C
155
```
(Heat Transfer)
according to Kirchhoff's law, for a gray body, the _____and ______ are equal even if the body is not in thermal equilibrium with its surroundings
A. absorptivity, reflectivity
B. absorptivity, emissivity
C. emissivity, thermal conductivity
D. reflectivity, thermal conductivity
```
B
156
(Heat Transfer)
which of the following is false?
A. monatomic and diatomic gases are virtually transparent to infrared radiation
B. polyatomic gases absorb radiation fairly strongly
C. absorptivity of a given gas is a strong function of its thermal conductivity
D. emissivity of a given gas is a function of temperature and pressure
C
157
```
(Heat Transfer)
the total emissive power is the total amount of radiation energy per unit area leaving a surface with temperature T overall wavelengths
A. stefan-boltzmann law
B. planck's law
C. Kirchhoff's law
D. Kick's law
```
A
| This law is derived from integrating planck's law
158
(Heat Transfer)
which of the following is true?
A. total emissive power increases as temperature increases
B. total emissive power decreases as temperature increases
C. total emissive power increases as temperature increases to a certain point then decreases
D. total emissive power decreases as temperature increases to a certain point then increases
A
E = σΤ^4
159
```
(Heat Transfer)
if a surface is totally enclosed in three different types of surfaces namely corkwood and 316L SS, what is the total view factor
A. 0
B. 0.25
C. 0.33
D. 1.0
```
D
| It will always be 1 if enclosed
160
(Heat Transfer)
which of the following is true?
A. the thermal conductivity k is a physical property of the substance
B. fourier's law states that k is independent of temperature but not necessarily of temperature gradient
C. for large temperature ranges, k maybe considered constant
D. the thermal conductivity of gases is dependent on pressure and decreases with temperature because of increase in molecular velocity
A
161
```
(Heat Transfer)
resistance and conductance depend on
A. dimensions of the solid
B. conductivity
C. temperature gradient
D. both a and b
```
D
162
(Heat Transfer)
which of the following is not a basic mechanism of heat transfer
A. the heat is conducted by the transfer of energy of motion between adjacent molecules
B. the heat is transferred by the bulk transport and mixing of macroscopic elements of warmer portions with color portions of a fluid
C. the heat is transferred through space by means of electromagnetic waves
D. none of the above
D
163
(Heat Transfer)
which of the following is true?
A. larger gas molecules have higher thermal conductivity since they can store more energy
B. the k of gasses varies approximately as the cube root of the absolute temperature
C. water has a lower thermal conductivity compared to organic liquids such as benzene
D. in metallic solids it is also conducted by free electrons which move through the metal lattice
D
164
(Heat Transfer)
in cases where there is a multi-layer wall of more than one material present in series, the total resistance of the system is
A. the sum of the individual resistances of the materials in series
B. the sum of the reciprocal of the individual resistances of the materials in series
C. the difference of the resistance of the outer materials
D. the reciprocal of the highest resistance among the materials
A
165
```
(Heat Transfer)
what is the ratio of the conduction rate to the rate of thermal storage?
A. Biot number
B. Fourier number
C. Prandtl number
D. Lewis number
```
B
166
```
(Heat Transfer)
arrange the thermal conductivity of the following substances in increasing order 1. solid 2. solid metal 3. gas 4. liquid
A. 1234
B. 4231
C. 2143
D. 3412
```
D
167
(Heat Transfer)
Given the same flow rates, inlet and outlet temperatures and heat transfer coefficient, which of the following is true?
A. Countercurrent flow is more preferred due to smaller area requirement
B. Parallel flow is more preferred due to smaller area requirement
C. Either parallel or countercurrent flow is desirable since both will require equal areas
D. none of the above
A
168
(Heat Transfer)
Which of the following is true?
A. High pressure liquid should be placed on the shell side of a S&T heat exchanger
B. Corrosive fluid should be placed on the shell side of a S&T heat exchanger
C. Fouling fluid should be placed on the shell side of a S&T heat exchanger
D. none of the above
D
169
```
(Heat Transfer)
A statement that relates the heat transfer and fluid friction that applies over a wide range of Prandtl numbers
A. Colburn analogy
B. Reynolds analogy
C. Chilton analogy
D. Sieder-Tate Analogy
```
A
170
```
(Heat Transfer)
The ratio of diffusivity of heat to the diffusivity of mass
A. Prandtl Number
B. Lewis Number
C. Peclet Number
D. Stanton Number
```
B
171
```
(Heat Transfer)
if the thermal conductivity of the fluid increases the heat transfer coefficient will
A. increase
B. decrease
C. remain the same
D. none of these
```
A
172
```
(Heat Transfer)
if the viscosity of the fluid will increase the heat transfer coefficient in a turbulent flow system will
A. increase
B. remain the same
C. decrease
D. none of these
```
C
173
```
(Heat Transfer)
in a fluid if the currents are set in motion by the action of a mechanical device and the flow is independent of density gradients the phenomenon is called
A. natural convection
B forced convection
C. thermal conduction
D. centrifugation
```
B
174
(Heat Transfer)
heat transferred radially across an insulated pipe per unit area
A. remains constant
B.is inversely proportional to the thermal conductivity
C. decreases from pipe wall to the insulated surface
D. increases from pipe wall to the insulated surface the insulated surface
C
175
(Heat Transfer)
it is a method of developing the design for a heat exchanger wherein the engineer assures the existence of an exchanger and makes calculation to determine if the exchanger would handle the process requirements under reasonable conditions
A. heat exchanger modeling
B.heat exchanger calculation
C. rating a heat exchanger
D. evaluation of heat exchanger performance
C
176
```
(Heat Transfer)
when water inside the beaker is being heated over a hot plate the mechanism of heat transfer through the water is considered to be
A. conduction
B. forced convection
C. natural convection
D.radiation
```
C
177
```
(Heat Transfer)
for a system where air is flowing inside the pipe well being heated by condensing steam outside the pipe, the proper U and A to be used is
A. based on the inside area
B. based on the outside area
C. it does not matter
D. none of these
```
A
178
```
(Heat Transfer)
the term hd/k is known as
A. prandtl number
B. peclet number
C. nusselt number
D. reynolds number
```
C
179
```
(Heat Transfer)
in heat transfer by conduction due to symmetry the heat flow at the point is perpendicular to the isothermal surface through the point. this mode of conduction is characteristic of
A. non isotropic solids
B. isotropic solids
C. insulators
D. conductors
```
B
180
```
(Heat Transfer)
ratio of the internal thermal resistance of a solid to the boundary layer thermal resistance is described by
A. nusselt number
B. prandtl number
C. biot number
D. reynolds number
```
C
181
```
(Heat Transfer)
the measure of the relative effectiveness of momentum and energy transport by diffusion in the velocity and thermal boundary layers is given by
A. nusselt number
B. prandtl number
C. biot number
D. reynolds number
```
B
182
```
(Heat Transfer)
the property of the solid that provides a measure of the rate of heat transfer relative to the energy storage is referred to as
A. thermal conductivity
B. heat capacity
C. thermal diffusivity
D. viscosity
```
C
183
```
(Heat Transfer)
the range of wavelengths of electromagnetic waves that is associated with thermal radiation is from
A. 10^-5 to 10^-2 μm
B. 0.1 to 100 μm
C. 100 to 1000 μm
D. none of these
```
B
184
```
(Heat Transfer)
the spectral distribution of a perfect emitter as a maximum and that the corresponding wavelength depends on temperature. the maximum spectral emissive power is displaced to shorter wavelengths with increasing temperature. these statements refer to
A. stefan-boltzman law
B. Kirchoff's Law
C. Wien's law
D. planck's law
```
C
185
```
(Heat Transfer)
the amount of radiation emitted in all directions and overall wavelengths by a perfect emitter is proportional to the fourth power of the absolute temperature of the emitter this is the statement of
A. Stefan-boltzman law
B. Kirchoff's Law
C. Wien's Law
D. Planck's Law
```
A
186
```
(Heat Transfer)
the ratio of the emissive power of a body to its absorptivity is a constant and the same for all radiating bodies in a confined and closure under thermal equilibrium. this is a statement of
A. Stefan-boltzman law
B. Kirchoff's Law
C. Wien's Law
D. Planck's Law
```
B
187
```
(Heat Transfer)
a theoretical body where the absorptivity and emissivity are independent of the wavelength over the spectral region of the irradiation and the surface emission is called
A. blackbody
B. gray body
C. opaque body
D. transparent body
```
B
188
(Heat Transfer)
thermal lumped analysis may be applied if
A. the thermal conductivity of the solid is very small
B. the convective resistance is very large
C. the convective resistance is very small compared with the conductive resistance
D. the conductive resistance is very small compared with the convective resistance
D
189
```
(Heat Transfer)
two parallel infinite walls at different temperatures are radiating energy to each other. if a sheet of negligible thermal resistance is placed midway between the walls and the sheet is considered a blackbody, the heat transfer by radiation between the two walls is
A. maintained the same
B. decreases
C. increases
D. cannot be determined
```
B
190
```
(Heat Transfer)
which among the gases list that is transparent to gas radiation
A. oxygen
B carbon dioxide
C. water vapor
D. ammonia
```
A (symmetric, when you stretch, it doesn't change the electric field)
191
```
(Heat Transfer)
in boiling the stage when the rate of bubble formation increases so that the velocity of circulation increases and the heat flux, q and ΔT also increase is referred to as
A. transition boiling
B. nucleate boiling
C. film boiling
D. rapid boiling
```
B
192
(Heat Transfer)
a semi-infinite solid in heat conduction is one where
A. only the conduction of one side effects the temperature distribution
B. the thickness is not so large
C. the length is semi-infinite
D. the heat flow on the surface is negligible
A
193
```
(Heat Transfer)
a 2-4 shell and tube heat exchanger means that there are
A. two tube passes and four shell passes
B. two baffles and four tubes
C. two shell passes and four tube passes
D. two baffles and four shells
```
B
194
```
(Heat Transfer)
air flowing inside the annular space for a double pipe heat exchanger is being heated by steam inside the inner pipe. for this case, the U in the heat transfer equation should be on
A. the outside area of the inner pipe
B. the inside area of the outer pipe
C. inside area of the inner pipe
D. it does not matter
```
A
195
```
(Adsorption)
it is an aluminosilicate adsorbent that is also used as catalyst in thermal cracking in petrochemical industries
A. activated carbon
B. zeolite
C. polypyrrol
D. silica gel
```
B. zeolite
196
```
(Adsorption)
what should be the signs of ΔG, ΔH and ΔS of an adsorption process?
A. +++
B. --+
C. ---
D. -+-
```
C
197
```
(Adsorption)
what is the bottom most zone in an operating adsorption tower
A. saturated
B. adsorption
C. work
D. non-work
```
D.
198
(Adsorption)
when adsorption hysteresis is observed the desorption equilibrium pressure is
A. always lower than that obtained by adsorption
B. always higher than that obtained by adsorption
C. same as that obtained by absorption
D. dependent on the system during the adsorption process
A
199
```
(Adsorption)
if the fluid velocity is sufficiently small the adsorption curve is steeper. the height of unusable bed height will then be
A. Low
B. High
C. Same
D. None of these
```
A.
200
```
(GenInorgChem)
which of the following is the most probable solute-solvent pair?
A. ethanol-kerosene
B. isooctane-heptane
C. benzene-water
D. Na-Br diesel
```
B
201
(Leaching)
the major problem in leaching is to promote diffusion of the solute out of the solid and into the liquid. the most effective way of doing this is to
A. reduce the solid to the smallest size feasible
B. to use counter current operation
C. to use cross-flow operation
D. none of these
B
202
(Leaching)
is there are two underflow-overflow leaching conditions namely ideal and non-ideal. the ideal leaching conditions exist if
A. the carrier solid is completely inert and is not dissolved or entrained in the solvent
B. the solute is infinitely soluble in the solvent
C. sufficient contact time exists for the solvent to penetrate the solute completely
D. all of these
D
203
(Leaching)
in non ideal leaching conditions, the tie lines slant to the right indicating that the solute is more highly concentrated in the underflow because
A. of equilibrium solubility or of incomplete leaching
B. the solvent and solute are completely miscible
C. of a partially miscible carrier or incomplete settling
D. all of these
A
204
(Leaching)
in leaching the particle size influences the extraction rate, the smaller the size,
A. the greater is the interfacial area between the solid and liquid
B. the smaller the distance the solute must diffuse within the solid
C. both a and b
D. the lower is the rate of transfer of material
C
205
(Leaching)
agitation of the liquid influences the rate of extraction. agitation of solvent is important because
A. it prevents sedimentation
B. it increases eddy diffusion
C. it increases the transfer of material from the surface of the particles to the bulk of solution
D. both b and c
D
206
```
(Leaching)
the temperature also affects the rate of extraction. in most cases the solubility of the material which is being extracted will increase with temperature to
A. give a higher rate of extraction
B. increase the diffusion coefficient
C. prevention of enzyme action
D. both a and b
```
D
207
(Leaching)
which of the following operations does not involve leaching
A. dissolving gold from ores
B. dissolving pharmaceutical products from bark or roots
C. dissolving sugar from the cells of the beet
D. removing nicotine from its water solution by kerosene
D
208
```
tea percolation employs
A. liquid liquid extraction
b. leaching
C. absorption
D. adsorption
```
b
209
```
(Leaching)
the rate of leaching increases with increasing
A. temperature
B. viscosity of the solvent
C. pressure
D. size of the solid
```
A
210
(Leaching)
stage efficiency in the leaching process depends on the
A. time of contact between the solid and the solution
B. rate of diffusion of the solute through the solid and into the liquid
C. both a and b
D. vapor pressure of the solution
C
211
```
coffee extraction from its seed is done by
A. liquid liquid extraction
B. leaching
C. extractive distillation
D. steam distillation
```
B
212
```
(Leaching)
leaching of sugar from sugar beets is done using
A. hot water
B. hexane
C. dilute sulfuric acid
D. limewater
```
A
213
```
(Screening)
this is a screening equipment with rotating cylinder of perforated sheet material or wire screen; low capacity and efficiency type
A. trommel
B. vibrating screen
C. reels
D. oscillating screen
```
A
214
(Screening)
which of the following statements is false
A. the maximum capacity of a given screen is roughly proportional to the screen opening
B. screen efficiency and capacity are two opposing factors
C. reciprocating screens are used to handle dry light or vulcan materials light metal powders powdered foods and granular materials
D. in wet screening materials screen contains the natural moisture
D
215
```
(Screening)
a type of testing sieves which sizes vary by a fixed ratio of √2 or area twice as that of the next screen
A. Tyler
B. US
C. International
D. None
```
A
216
```
(Screening)
it is the material passing through one screen and retain on subsequent surface
A. undersized
B. intermediate
C. oversized
D. feed
```
B
217
```
(Screening)
the minimum clear space between the edges of the opening in the screening surface and is usually given in inches or mm
A. sieve
B. aperture
C. mesh number
D. holes
```
B
218
```
(Screening)
the screen used in making size separation smaller than 4-mesh and larger than 48-mesh
A. grizzly screen
B. gyratory screen
C. oscillating screen
D. vibrating screen
```
D
219
(Screening)
when the object is to recover an oversized product from the screen, efficiency may be expressed as
A. ratio of the amount of undersize obtained to the amount of undersize in the feed
B. using the Taggart formula E= [100(e-v)/e(100-v)]*100 where e= percentage of undersized in the feed; v=percentage of undersized in the screen oversize
C. ratio of the amount of oversize obtained to the amount of true oversize
D. none of these
C
220
```
(Screening)
box like machines, either round or square with the series of screen clothes nested atop one another
A. reciprocating screen
B. oscillating screen
C. electricity vibrated screen
D. gyratory screen
```
D
221
```
(Screening)
the removal of a small amount of oversize from a feed which are predominantly fines is called
A. scalping
B. desliming
C. coarse separation
D. dewatering
```
A
222
```
(Screening)
removal of free water from a solids water mixture and is generally limited to 4- mesh and above
A. scalping
B. dewatering
C. trash removal
D. separation
```
B
223
```
(Screening)
making a size separation smaller than 48 mesh is called
A. coarse separation
B. fine separation
C. ultrafine separation
D. scalping
```
C
224
```
(Screening)
another name for revolving screen is
A. shaking screen
B. vibrating screen
C. mechanically vibrated screen
D. trommel screen
```
D
225
(Screening)
the mesh number of a screen denotes
A. the area of the screen and square inch
B. the number of openings per linear inch of screen
C. the number of layers in a screen system
D. the number of screens needed to obtain the required fines
B
226
```
(Screening)
the wire diameter of a 14 mesh screen tyler standard is
A. 0.0235 in
B. 0.025 in
C. 0.028 in
D. 0.03 in
```
B
227
```
(Screening)
the wire diameter of a 10-mesh screen whose aperture is 0.065-inch is
A. 0.045 in
B. 0.025 in
C. 0.035 in
D. 0.05 in
```
C
Aperture = 1/mesh - diameter of wire
d = 1/10 - 0.065
d = 0.035 in
228
(Screening)
the tyler standard screen series is characterized by
A. square root of 2 ratio of areas between successive screens
B. square root of four ratio of linear openings between successive screens
C. twice the area ratio between successive screens
D. none of these
C
229
```
(Screening)
the ratio of the clear opening corresponding to a mesh size in the tyler standard screen series to that of the next smaller screen is
A. 2
B. √2
C. 1.5
D. none of these
```
B
230
```
(Screening)
the clear opening of a 200 mesh screen in the tyler standard screen series is
A. 0.0074 cm
B. 0.0074 mm
C. 0.0047 cm
D. 0.0047 mm
```
A
231
```
(Screening)
the ratio of the area of the opening in one screen tyler series to the opening of the next smaller screen is
A. 1.5
B. 1
C. √2
D. none of these
```
D
232
(Screening)
the cumulative screen analysis for determining the surface area of particles is more precise than the differential screen analysis because of the
A. assumption that all particles in a single fraction are equal in size
B. fact that screening is more effective
C. assumption that all particles in a single fraction are equal in size is not needed
D. none of these
C
233
```
(Screening)
increasing the capacity of a screen
A. decreases the screen effectiveness
B. increases the screen effectiveness
C. does not affect the screen effectiveness
D. none of these
```
A
234
```
(Screening)
the screen efficiency is
A. recovery + rejection
B. recovery
C. rejection
D. none of these
```
D
235
(Screening)
as the particle size is reduced
A. screening becomes progressively more difficult
B. screening becomes progressively easier
C. capacity and effectiveness of the screen is increased
D. none of these
A
236
(Screening)
a screen is said to be blinded when
A. oversize are present in undersize fraction
B. undersize are retained in oversize fraction
C. the screen is plugged with solid particles
D. its capacity is abruptly increase
C
237
```
(Screening)
size measurement of ultrafine particles can be best expressed in terms of
A. cm
B. screen size
C. micron
D. surface area per unit mass
```
D
238
```
(Screening)
trommels separate a mixture of particles depending on their
A. size
B. wettability
C. screen size
D. electrical and magazine
```
A
239
```
(Screening)
screen capacity is expressed in terms of
A. tons/h
B. tons/ft^2
C. both a and b
D. tons/h-ft^2
```
D
240
```
the term applied to all ways in which particles of solids are cut or broken into smaller pieces
A. size reduction
B. screening
C. comminution
D. crushing
```
A
241
```
(Size Reduction)
the hardness of a mineral is a criterion of its resistance to crushing. which of the following is an example of a hard material?
A. talc
B. calcite
C. sapphire
D. feldspar
```
C
242
```
(Size Reduction)
states that the energy required for crushing is proportional to the new surface created.
A. Rittingger's law
B. Kick's Law
C. Bond Law
D. Energy Law
```
A
243
```
(Size Reduction)
it is defined as the efficiency of technical grinding compared with that of laboratory crushing experiments
A. grinding efficiency
B. bond work index
C. practical energy efficiency
D. none of these
```
C
244
(Size Reduction)
in comminution the energy requirement is determined theoreticalyl by
A. the initial and final sizes of the particles
B. the type of equipment
C. the change in shape of the particle
D. none of these
A
245
(Size Reduction)
size reduction is important in chemical engineering since
A. it prevents chemical engineers from becoming overweight
B. it makes products to become uniform in size
C. it prepares raw materials of the desired sizes prior to processing
D. none of these
C
246
```
(Size Reduction)
based on bond's crushing law the power required to crush a certain material will change by what percent if the diameter of the product is made smaller by 50%
A. 50%
B. 41%
C. 25%
D. 75%
```
B
(1/√X2 - 1/√X1)
where X2 is 0.5 and X1 is 1
247
(Size Reduction)
equivalent diameter of a particle is a diameter of the sphere having the same
A. ratio of surface to volume as the actual volume
B. ratio of volume to surface as the particle
C. volume as the particle
D. none of these
A
248
```
(Size Reduction)
for coarse reduction of hard solids, use
A. impact
B. attrition
C. compression
D. cutting
```
C
249
```
(Size Reduction)
soft and non abrasive materials can be made into fines by
A. attrition
B. compression
C. cutting
D. none of these
```
A
250
(Size Reduction)
crushing efficiency is the ratio of
A. surface energy created by the crushing to the energy absorbed by the solid
B. energy absorbed by the solid to that fed to the machine
C. energy fed to the machine to the surface energy created by the crushing
D. energy absorbed by the solid to the surface energy created by the crushing
A
251
(Size Reduction)
rittinger's crushing law states that
A. work required to form a particle of any size is proportional to the square of the surface to volume ratio of the product
B. work required to form a particle of a particular size is proportional to the square root of the surface to volume ratio of the product
C. work required in crushing is proportional to the new surface created
D. for a given machine and feed, crushing efficiency is dependent on the sizes of feed and product
C
252
(Size Reduction)
bond crushing law
A. calls for relatively less energy for the smaller product particle than does the rittinger's law
B. less realistic in estimating the power requirements of commercial crushes
C. states that the work required to form particle of any size from very large feed is proportional to the square root of the volume to surface ratio of the product
D. states that the work required for crushing is proportion
A
253
(Size Reduction)
work index is defined as the
A. gross energy (kWh/ton of feed) needed to reduce very large feed to such a size that 80% of the product passes a 100 micron screen
B. energy needed to crush 1 ton of feed to 200 microns
C. energy needed to crush a small feed to such a size that 80% of product passes at 200 mesh screen
D. energy needed to crush 1 on feed to 100 microns
A
254
```
(Size Reduction)
the operating speed of a ball mill should be
A. less than the critical speed
B. much more than the critical speed
C. at least equal to the critical speed
D. none of these
```
A
255
```
(Size Reduction)
a fluid energy mill is used for
A. cutting
B. grinding
C. ultra grinding
D. crushing
```
C
256
(Size Reduction)
wet grinding in a revolving mill
A. gives less wear on chamber walls than dry grinding
B. requires more energy than for dry grinding
C. increases capacity compared to dry grinding
D. complicates handling of the product compared to a dry grinding
C
257
```
(Size Reduction)
cement clinker is commonly reduced to fine size using a
A. roll crusher
B. ball mill
C. tube mill
D. hammer mill
```
C
258
```
(Materials Handling)
a solids handling equipment used to handle large volumes over long distances economically is a
A. pneumatic conveyor
B. belt conveyor
C. bucket elevators
D. screw conveyor
```
B
259
```
(Materials Handling)
a solid handling equipment used for moving powdered or granular materials to and from storage or between reaction vessels as in moving bed catalytic
A. bucket elevator
B. screw conveyor
C. belt conveyor
D. pneumatic conveyor
```
A
260
```
(Materials Handling)
which of the following conveyors for bulk materials is used for handling materials over a combination of horizontal and vertical path
A. continuous flow
B. gravity discharge bucket
C. pivoted bucket
D. all of these
```
D
261
```
(Materials Handling)
the bulk density of potassium chloride in lb/ft^3 is
A. 75
B. 77
C. 85
D. 60
```
B. 77
262
```
(Materials Handling)
the bulk density of impure aluminum oxide in lb/ft^3 is
A. 90
B. 70
C. 80
D. 60
```
C. 80
263
```
(Materials Handling)
a type of pneumatic conveyor system characterized by a material moving in an airstream or pressure less than ambient is
A. fluidizing
B. pressure
C. pressure-vacuum
D. vacuum
```
D
264
```
(Materials Handling)
A conveyor auxiliary device with the driving force when a conveyor jams
A. brake
B. hold back
C. torque- limiting
D. cleaner
```
D
265
```
(Materials Handling)
a bucket elevator used for large lump materials and effective for handling finely pulverized or aerated materials
A. continuous
B. centrifugal discharge
C. positive discharge
D. oscillating
```
A
266
```
(Materials Handling)
the supports for a belt conveyor rollers on shaft support and permits the belts for a with to carry more material per linear foot without spillage are called
A. chains
B. idlers
C. feeder
D. scrapers
```
B
267
```
(Materials Handling)
the method used to discharge a belt conveyor depends on whether or not the discharge is from the end of the conveyor or at some intermediate point. special devices are necessary for discharge at discharge points. which of the following devices consists of a discharge and return pulleys and are so mounted that the belt is doubled back for a short distance ?
A. scraper
B. tipping idler
C. shuttle conveyor
D. tripper
```
D
268
```
(Materials Handling)
which is the most suitable for transportation of sticky material
a. apron conveyor
b. screw conveyor
c. belt conveyor
d. pneumatic conveyor
```
B
269
```
(Materials Handling)
which of the following cannot be recommended for transportation of abrasive materials
A. belt conveyor
B. flight conveyor
C. apron conveyor
D. chain conveyor
```
B
270
```
(Materials Handling)
for transporting pastry material one will use
A. apron conveyor
B. screw conveyor
C. belt conveyor
D. bucket elevator
```
B
271
```
(Materials Handling)
the capacity of a belt conveyor depends upon two factors. if one is the cross section of the load, the other is the
A. speed of the belt
B. length of the belt
C. thickness of the belt
D. material to be transported
```
A
272
```
(Materials Handling)
dry powdery solid materials are transported by a
A. belt conveyor
B. screw conveyor
C. bucket elevator
D. all of these
```
B
273
```
(Materials Handling)
this is a type of temporary installation usually used for solids weighing more than 5 tons moved at distances greater than 10 feet to a maximum of 200 feet examples are wheelbarrows hand pallets & carts
A. assisted manpower
B. unassisted manpower
C. power-driven machines
D. none of the above
```
A
274
```
(Materials Handling)
conveyor consists of endless belts suitably supported and driven can travel for miles at speeds up to 1000 ft/min and handle up to 5,000 tons/hr
A. belt conveyor
B. screw conveyor
C. bucket elevator
D. vibrator
```
A
275
```
(Materials Handling)
which of the following is not a component of the total power requirement for belt conveyors
A. power to drive empty belt
B. power to move material horizontally
C. power to oppose the fast movement
D. power to operate tripper
```
C
276
```
(Materials Handling)
this is similar to belt conveyor that solids are carried via moving through, but it is formed of articulating sections of wood or metal instead of a continuous flexible belt. it is usually used for lumpy abrasive and hot materials
A. apron
B. flight
C. closed belt
D. screw
```
A
277
```
(Materials Handling)
which of the following is not a type of pneumatic conveyor?
A. vacuum system
B. pressure vacuum system
C. blowtank
D. continuous system
```
D
278
```
(Materials Handling)
which of the following has the highest coefficient of material
A. ash
B. coal
C. grain
D. all are the same
```
A
279
```
(Size Reduction)
this material property refers to its tendency to fracture during normal handling
A. friability
B. soapiness
C. stickiness
D. hardness
```
A
280
```
(Size Reduction)
this is a type of grinding where an aggregate of smaller particles is size-reduced by breaking clusters of particles of the main aggregate without breaking any of the primary particles that form the aggregates
A. particle fracture
B. super grinding
C. deagglomeration
D. dispersion
```
C
281
(Size Reduction)
the following is an objective of size reduction
A. to disable metal surfaces from interacting with an acidic media
B. to easily manage generated solid wastes
C. to enable customers buying half of a particular product sold as a whole
D. both a and c
B
282
```
(Size Reduction)
the size reduction operation where the product oversize is returned to the feed hopper to further improve reduction in the particle size
A. free crushing
B. choke feeding
C. closed- circuit
D. open circuit
```
C
283
```
(Evaporation)
the feed condition is usually dilute thus the viscosity is ____ and the convective heat transfer coefficient is ____
A. high, high
B. high, low
C. low, low
D. low, high
```
D
284
```
(Evaporation)
it occurs when products such as milk forms foam when heated which causes entrainment losses
A. weeping
B. frothing
C. scaling
D. bubbling
```
B
285
```
(Evaporation)
LTV evaporators have the following advantages except
A. high headroom
B. low cost
C. high transfer coefficient
D. low hold up
```
A
286
```
(Evaporation)
when the pressure of the evaporator chamber is decreased the boiling point of the solution inside the chamber will
A. increase
B. remain the same
C. decrease
D. none of these
```
C
287
```
the concentration of glycerine from a water solution by the application of heat is
A. distillation
B. evaporation
C. crystallization
D. reverse osmosis
```
B
288
(Evaporation)
which of the two evaporator flow configurations needs fluid motive devices to transfer solution from one effect to the other effect
A. feed forward
B. backward flow
B
289
```
(Evaporation)
a heat transfer device that is normally used to liquefy vapors is
A. evaporator
B. condenser
C. reboiler
D. none of these
```
B
290
(Evaporation)
in a country where capital is scarce and energy cost is low which is appropriate to install
A. multiple effect evaporator
B. single effect evaporator
B
291
```
(Evaporation)
in evaporation operation the valuable product is called
A. thick liquor
B. vapor
C. water
D. residue
```
A
292
```
(Evaporation)
for the same duty and heat transfer area, the feedforward flow evaporator is ____ compared to the backward flow evaporator in terms of heat transfer.
A. more efficient
B. less efficient
C. just the same
D. none of these
```
B
293
```
(Evaporation)
the temperature driving force in an evaporator is determined as the difference between the condensing steam temperature and
A. condenser temperature
B. boiling point of the solvent
C. boiling point of the solution
D. BPR of the solution
```
C
294
```
(Evaporation)
if the solution to be evaporated tends to strongly scale or form salt the type of evaporator to be recommended is
A. long tube vertical
B. horizontal tube
C. forced circulation
D. natural circulation
```
C
295
```
(Drying)
this is the moisture that can be removed by drying under the given percent relative humidity
A. Equilibrium
B. Critical
C. Free
D. Bound
```
C
296
```
(Drying)
rapid drying of solutions and suspensions in hot air or gas with dry particles or powders as product
A. tray
B. Supersonic
C. Spray
D. splash
```
C
297
```
(Drying)
the value of constant rate of drying, Rc varies directly with quantity (Hs-H), therefore increasing the humidity
A. increases the rate of drying
B. no effect on the rate of drying
C. decreases the rate of drying
D. none of these
```
C
298
(LLE)
which of the following is true about partition ratio?
A. K<=1 is desirable since it is more economical
B. K is the ratio of the amount of solute in the extract phase amount of solute in the raffinate phase when the equilibrium has been attained after one stage of contact
C. higher K is desirable since it maximizes the use of the extract solvent
D. K can be a strong function of composition temperature and method of extraction
C
299
```
(LLE)
in packed towers used for liquid liquid extraction, if the flow rate of either the dispersed phase or the continuous phase is held constant and that of the other phase gradually increased, a point is reached where the dispersed phase coalesces, the holdup of that phase increases and finally both faces leave together through the continuous phase outlet. this effect is called
A. flooding
B. channeling
C. settling
D. back mixing
```
A
300
```
(LLE)
point wherein the composition of the extract phase is the same as the raffinate phase, thus, no extraction is possible
A. tieline
B. plait point
C. pure solvent point
D. pinch point
```
B
301
```
(LLE)
point were in the theoretical number of stage required for the desired separation is infinite. this decides the limit of the operation
A. tieline
B. plait point
C. pure solvent point
D. pinch point
```
D
302
```
unit operation most suitable separating heat sensitive liquid component in a mixture and that has similar densities
A. filtration
B. centrifugation
C. membrane separation
D. liquid liquid extraction
```
D
303
```
(LLE)
in a ternary diagram the corners of the equilateral triangle corresponds to a
A. pure component
B. ternary mixture
C. binary mixture
D. solute
```
A
304
(LLE)
in operating a countercurrent extractor with reflux
A. as reflux ratio increases the number of stages approaches infinity
B. as reflux ratio increases the number of stages approaches a minimum
C. there is no relationship with reflux ratio and the number of stages, unlike distillation
D. none of the above.
B
305
```
(LLE)
handling dilute to moderately concentrated feeds for the recovery of acetic acid is best done using
A. liquid liquid extraction
B. evaporation
C. distillation
D. centrifugation
```
A
306
```
(LLE)
an extraction scheme in which the extraction solvent enters the stage or end of the extraction farthest from where the feed enters and the two phases pass each other from opposite directions
A. cross current extraction
B. countercurrent extraction
C. fractional extraction
D. differential extraction
```
B
307
```
(LLE)
in ternary diagrams the bimodal curve decreases as
A. temperature increases
B. temperature decreases
C. temperature remains constant
D. none of the above
```
A
308
```
(LLE)
liquid liquid extraction is based on the difference in
A. solubility
B. partial pressure
C. viscosity
D. specific volume
```
A
309
```
(Filtration)
Which of the following is not a component of filtration?
A. medium
B. slurry
C. gangue
D. Cake
```
C
310
```
(Filtration)
what is the mode of operation when high pressures are applied causing the solids to rapidly form resistance?
A. CPF
B. CRF
C. CRF-CPF
D. gravity filtration
```
A
311
```
(Filtration)
which type of filter is tightly combined into a series of modules to form an assembly?
A. tubular
B. plate-and-frame
C. rotary vacuum
D. leaf
```
B
312
```
(Filtration)
which type of filter is operated inside a horizontal tank with several units that can filter at relatively high pressures
A. tubular
B. plate-and-frame
C. rotary vacuum
D. leaf
```
D
313
```
(Fluidization)
which parameter is being directly controlled during fluidization
A. bed height
B. fluid velocity
C. porosity
D. particle diameter
```
B
314
```
(Fluidization)
all of the following are particle properties considered for fluidization except
A. bulk density
B. diameter
C. true density
D. sphericity
```
A
315
```
(Fluidization)
which parameter is being directly controlled during fluidization?
A. bed height
B. fluid velocity
C. porosity
D. particle diameter
```
B
316
```
(Fluidization)
all of the following are particle properties considered for fluidization except
A. bulk density
B. diameter
C. true density
D. sphericity
```
A
317
```
(Fluidization)
the ergun equation can be simplified by ignoring one term. what equation is derived under very viscous conditions?
A. Burke-Plummer
B. Ruth
C. Carman-Kozeny
D. Reynolds
```
C
318
```
(Fluidization)
fluidization is achieved when the ____ is reached
A. superficial velocity
B. minimum fluidizing velocity
C. terminal settling velocity
D. interstitial velocity
```
B
319
(Fluidization)
which of the following statements is false?
A. a bed is mobilized once the terminal settling velocity is exceeded
B. porosity changes with bed height
C. spheres have a sphericity of one
D. the pressure drop increases with superficial velocity for a fluidized bed
D
320
```
(Humidification)
it is the amount of heat required to raise the temperature of 1 kg dry air plus the moisture it contains by 1 K or 1 °C.
A. humid heat
B. sensible heat
C. convective heat
D. latent heat
```
A
321
```
(Humidification)
the process for water vapor is added to the air without changing its dry-bulb temperature
A. dehumidification
B. evaporation
C. humidification
D. psychrometry
```
C
322
```
(Humidification)
it is the volume occupied by 1 kg saturated air-water vapor mixture at 1 atm absolute pressure and the given gas temperature
A. humid volume
B. humidity
C. total enthalpy
D. saturated volume
```
D
323
```
(Humidification)
the analysis developed by merkel for cooling towers is based upon which driving force
A. density difference
B. specific volume difference
C. enthalpy potential difference
D. tower height
```
C
324
(Humidification)
which of the following statements is false
A. an approach less than 2.8 °C is an economic design for cooling towers
B. evaporative cooling process involves both latent and heat transfer
C. majority of the evaporative cooling heat transfer is due to latent heat
D. the cooling tower size is a function of the tower height
A
325
(Crystallization)
which of the following is true?
A. the mass fraction of anhydrous crystal in the mother liquor is greater than 1
B. the mass fraction of anhydrous crystal in the crystal stream is less than one
C. the feed is always equal to the sum of crystal stream and mother liquor
D. none of the above
D
326
```
(Crystallization)
which of the following is not a method of crystallization
A. lowering the temperature
B. adiabatic evaporative heating
C. vaporization of solvent
D. addition of seed crystal
```
B
327
```
(Crystallization)
which of the following feels cold to the touch upon crystallization
A. calcium nitrate tetrahydrate
B. potassium sulfate
C. plumbous chloride
D. zinc sulfate monohydrate
```
D
328
```
(Crystallization)
the solution that leaves the crystallizer is
A. unsaturated
B. saturated
C. supersaturated
D. any of these
```
B
